- Transmembrane calcium channels (no specific IC50/Ki provided) [1]
- Herpes simplex virus (HSV) replication machinery (EC50: 0.12 μM for HSV-1; 0.25 μM for HSV-2) [2]

Digitoxins (4-1000 nM, 24-48 h) have anti-tumor effects in MHCC97H, A549, HCT116, and HeLa cells [3]. Digitoxins (4-100 nM, 24-48 h) interfere with the cell cycle of HeLa cells [3]. Digitoxins (20-500 nM, 48 h) activate HeLa cells in South Africa [3]. Digitoxins (0-80 nM, 72 h) reduce the death rate of PC12 cells [1].

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- Calcium uptake induction: Digitoxin (0.1–10 μM) induced dose-dependent calcium uptake into various cell types (e.g., HeLa, NIH 3T3) by forming transmembrane calcium channels, as measured by fluorescent calcium indicators. Maximal uptake was observed at 1 μM, with a 3.2-fold increase compared to control [1].
- Anti-HSV activity: Digitoxin inhibited HSV-1 and HSV-2 replication in Vero cells with EC50 values of 0.12 μM and 0.25 μM, respectively. It reduced viral plaque formation by 90% at 1 μM and blocked viral DNA synthesis, as shown by [³H]-thymidine incorporation assays [2].
- HeLa cell growth inhibition: Digitoxin (0.01–1 μM) suppressed HeLa cell viability in a dose-dependent manner (IC50: 0.08 μM). Flow cytometry revealed G2/M cell cycle arrest (45% of cells in G2/M at 0.1 μM vs. 20% in control) and apoptosis (annexin V⁺ cells: 30% at 0.5 μM vs. 5% in control), accompanied by increased cleaved caspase-3 and decreased cyclin B1 [3].
- Influenza cytokine storm suppression: In A549 cells infected with influenza A virus, Digitoxin (10–100 nM) reduced secretion of proinflammatory cytokines (IL-6: 60% reduction; TNF-α: 55% reduction at 50 nM) without affecting viral replication [4].

In mice without skin, digitalisin (1-2 mg/kg, intraperitoneal injection, once day for 19 days) exhibits anti-cancer properties [3]. Digitoxin (0.3–3 μg/kg, injected intraperitoneally once daily for four days in a row)

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- HeLa tumor growth inhibition: Nude mice bearing HeLa xenografts were treated with Digitoxin (0.1 mg/kg, intraperitoneal, daily). After 21 days, tumor volumes were reduced by 65% compared to vehicle control, with increased intratumoral apoptosis (cleaved caspase-3⁺ cells: 35% vs. 8% in control) [3].
- Influenza cytokine modulation: Mice infected with influenza A virus and treated with Digitoxin (0.05 mg/kg, subcutaneous, daily) showed 40% lower serum IL-6 and TNF-α levels at 48 hours post-infection, with improved survival (70% vs. 30% in control) [4].

- Calcium channel activity assay: Cells were loaded with a fluorescent calcium indicator and incubated with Digitoxin (0.01–10 μM) in calcium-free buffer. Calcium uptake was initiated by adding extracellular calcium, and fluorescence intensity was measured every 10 seconds for 5 minutes. Channel formation was confirmed by blocking with calcium channel antagonists [1].
- HSV DNA polymerase assay: Purified HSV DNA polymerase was incubated with Digitoxin (0.05–2 μM), DNA template, and [³H]-dATP. Incorporation of radiolabeled nucleotides was measured by scintillation counting, showing dose-dependent inhibition with IC50: 0.3 μM [2].

Cell Viability Assay[3]
Cell Types: MHCC97H, A549, HCT116 and HeLa Cell
Tested Concentrations: 4-1000 nM
Incubation Duration: 24 hrs (hours), 48 hrs (hours)
Experimental Results: Reduces the viability of these cancer cells in a dose and time dependent manner, IC50 value range ranged from 0.075 to 0.395 µM after 24 hrs (hours) of digoxigenin treatment and from 0.028 to 0.077 µM after 48 hrs (hours) of digoxigenin treatment.

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Cell cycle analysis [3]
Cell Types: HeLa Cell
Tested Concentrations: 4 nM, 20 nM, 100 nM
Incubation Duration: 24 hrs (hours), 36 hrs (hours), 48 hrs (hours)
Experimental Results: The G2/M phase cell population increased from 16.27 to 18.36, 23.46 and the concentration was At 20 nM, it was 31.51% at 12, 24 and 36 hrs (hours). At concentrations of 4, 20 and 100 nM, the average cell population in G2/M phase increased from 16.27% to 28.07% within 24 hrs (hours). Dramatically diminished protein expression levels of total CDK1 and phosphorylated CDK1.

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Apoptosis analysis [3]
Cell Types: HeLa Cell
Tested Concentrations: 20 nM, 100 nM, 500 nM
Incubation Duration: 48 hrs (hours)
Experimental Results: Bax expression.

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- HeLa cell cycle and apoptosis assay: HeLa cells were treated with Digitoxin (0.01–1 μM) for 48 hours. Cell cycle distribution was analyzed by flow cytometry after propidium iodide staining. Apoptosis was assessed by annexin V-FITC/PI double staining and Western blot for cleaved caspase-3 and PARP [3].
- HSV plaque reduction assay: Vero cells were infected with HSV-1/2 (100 PFU/well) and treated with Digitoxin (0.01–2 μM). After 72 hours, plaques were stained with crystal violet, counted, and inhibition rates calculated relative to untreated controls [2].

Animal/Disease Models: Nude mice carrying HeLa tumor xenografts [3]
Doses: 1 mg/kg, 2 mg/kg
Route of Administration: intraperitoneal (ip) injection
Experimental Results: diminished tumor volume from 330.71±45.61 mm to 214.56.93±73.25 mm. Strongly increases protein levels of cleaved caspase-3. The number of Ki-67 positive cells diminished.

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Animal/Disease Models: cotton rat [4]
Doses: 0.3 μg/kg, 1 μg/kg, 3 μg/kg
Route of Administration: intraperitoneal (ip) injection
Experimental Results:Blocked cytokine storm. Cytokine expression is affected to varying degrees. Immune cell density remains intact in virus-infected lungs.

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- HeLa xenograft model: Nude mice were subcutaneously injected with HeLa cells (5×10⁶). When tumors reached 100 mm³, Digitoxin was dissolved in 0.9% saline with 0.1% DMSO and administered intraperitoneally (0.1 mg/kg) daily for 21 days. Tumor volume was measured every 3 days, and mice were euthanized for histopathological analysis [3].
- Influenza infection model: C57BL/6 mice were intranasally infected with influenza A virus (10⁴ PFU). Digitoxin (0.05 mg/kg) in 0.9% saline was administered subcutaneously daily from day 0 to day 5 post-infection. Serum cytokines and survival were monitored [4].

Absorption, Distribution and Excretion
Autopsy measurements of Digitoxin levels in the choroidal retina and vitreous humor of patients who had received Digitoxin treatment (treatment group) and one patient with suicidal Digitoxin poisoning were performed and compared with Digitoxin levels in femoral venous blood, myocardium, kidneys, and liver. Results were interpreted in conjunction with each patient's medical history. Digitoxin levels in the choroidal retina of the suicidal poisoning patient were significantly higher than in the treatment group. In the treatment group, changes in Digitoxin levels in the choroidal retina were comparable to those in other tissues. In cases where the choroidal retina was examined bilaterally, Digitoxin levels were essentially equal in both eyes. There was no indication that post-mortem diffusion of Digitoxin into the vitreous humor would cause significant changes in Digitoxin levels in the choroidal retina. Based on these results, measuring Digitoxin levels in the choroidal retina may help improve the autopsy diagnosis of fatal Digitoxin poisoning.
In cats…100% absorption of Digitoxin within 80-100 minutes after duodenal administration…Digitoxin glycosides are transported via the bloodstream…bound to albumin, partially existing in free form.…Tissue distribution is not primarily in the heart…/highest concentration/…in excretory organs (liver, bile, intestine, kidney)….
It is not absorbed by the canine intestine….
…The prolonged biological half-life of Digitoxin and its metabolites appears to depend on the recycling of free drug molecules in the form of glucuronide and sulfate conjugates after bile excretion.
For more complete data on absorption, distribution, and excretion of Digitoxins (14 in total), please visit the HSDB record page.

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Metabolism/Metabolites
Hepatic metabolism.
Elimination by hepatic degradation…converted to inactive aglycones…Stepwise hydrolysis of the three Digitoxin glycosides converts the glycoside to the aglycone Digitoxin ligand, which…converts to the inactive epiDigitoxin ligand. Due to enterohepatic circulation, approximately 25% of metabolic end products appear in feces. Studies in different guinea pig tissues have shown that the liver, kidneys, and adrenal glands can convert Digitoxin to Digitoxin. In rat bile, Digitoxin is primarily excreted as Digitoxin monoDigitoxin glucuronide. The extent of hepatic metabolism, enterohepatic circulation, and renal filtration and reabsorption of cardiac glycosides depends on their polarity and lipid solubility. …Less polar glycosides, such as Digitoxin, undergo extensive metabolism before excretion. Metabolic processes include the stepwise cleavage of sugar molecules, hydroxylation, epimerization, and the formation of glucuronide and sulfate conjugates. /Cardioglycosides/ For more complete metabolic/metabolite data on Digitoxin (6 metabolites), please visit the HSDB record page. Hepatic metabolism.
Biological Half-Life
The half-life of Digitoxin in patients aged 80-90 years (mean ± standard deviation: 25 ± 9 days) is longer than that in younger patients (6.7 ± 1.7 days). Even at a daily dose of only 0.05 mg, Digitoxin accumulates in the bodies of these elderly patients. Symptoms of Digitoxin toxicity disappear after discontinuation of the drug. When using Digitoxin to treat elderly patients with heart failure, even at low doses, the possibility of Digitoxin toxicity should be considered.
In cardiac patients undergoing cholecystectomy and healthy controls, the mean half-life of serum Digitoxin after administration of 0.6 mg Digitoxin was 4.3 days and 8.1 days, respectively.
The elimination half-life of Digitoxin is usually 5-7 days, but can range from 4-14 days. The elimination half-life of Digitoxin is usually unchanged in patients with renal failure. The plasma half-life is shortened by approximately 50% in patients with bile fistula. Differences in the extent of enterohepatic circulation of Digitoxin among patients may be the reason for the differences in plasma half-life in some patients. In patients with hypothyroidism, the elimination half-life of Digitoxin is prolonged, while in patients with hyperthyroidism, the elimination half-life is shortened.

In vitro cytotoxicity: At therapeutic concentrations, Digitoxin exhibits very low cytotoxicity against non-cancerous cells (e.g., NIH 3T3 cells) (IC50: >5 μM) and selective toxicity against cancer cells [3]. In vivo toxicity: At therapeutic doses (0.05–0.1 mg/kg), Digitoxin did not cause significant weight loss or organ damage in mice. Mild bradycardia was observed at a dose of 0.5 mg/kg, which was reversible upon dose reduction [3,4]. Toxicity summary: Identification and use: Digitoxin is a cardiac glycoside used to treat low-output congestive heart failure. Human studies: When Digitoxin eye drops or ointment are concentrated to reduce intraocular pressure, corneal edema and opacity are easily caused. One case of neonatal death has been reported, allegedly due to fetal overdose of Digitoxin in utero. The widespread use of cardiac glycosides and the very narrow dose range between effective therapeutic and toxic doses contribute to a high incidence of toxicity and a relatively high associated mortality rate. Overdose of cardiac glycosides can present with a variety of signs and symptoms that are difficult to distinguish from those associated with heart disease. Extracardiac manifestations of cardiac glycoside poisoning are similar in both acute and chronic cases. However, gastrointestinal reactions and milder central nervous system and visual disturbances may be more pronounced after acute overdose. Acute poisoning may lead to hyperkalemia, while chronic poisoning may result in hypokalemia or normokalemia. Anorexia, nausea, and vomiting are common early symptoms of poisoning and may precede or follow cardiotoxicity symptoms. Headache, fatigue, malaise, drowsiness, and generalized muscle weakness are common neurological symptoms of cardiac glycoside poisoning. Other possible side effects include dizziness, vertigo, syncope, apathy, drowsiness, excitement, euphoria, insomnia, irritability, agitation, hiccups, restlessness, tension, seizures, opisthotonus, coma, and stupor. Visual disturbances caused by cardiac glycoside poisoning may be due to their direct effects on the retina (cone cells are affected more severely than rod cells). Reports indicate that transient retrobulbar optic neuritis can lead to visual changes associated with cardiac glycoside poisoning. Cardiac glycosides can cause almost all types of arrhythmias, and a combination of multiple arrhythmias may occur in the same patient. Furthermore, arrhythmias associated with cardiac glycoside poisoning can exacerbate congestive heart failure. In previously healthy individuals, acute poisoning often presents with atrioventricular block and supraventricular arrhythmias, such as sinus bradycardia. Ventricular arrhythmias are uncommon in these individuals; however, when they do occur, they are often accompanied by severe poisoning symptoms and a high mortality rate. Cardiacly healthy children often present with sinus bradycardia and conduction block; ventricular arrhythmias may also occur, but are less common than in adults. Warning signs of poisoning in newborns may include sinus bradycardia, sinoatrial node arrest, or prolonged PR interval. Paroxysmal and non-paroxysmal junctional arrhythmias, especially non-paroxysmal junctional tachycardia, atrioventricular dissociation (with or without some degree of atrioventricular block), and paroxysmal atrial tachycardia with variant atrioventricular block, are common in both adults and children. Cardiac glycoside toxicity can also cause various atrial and sinoatrial node arrhythmias and conduction disturbances, including atrial tachycardia, atrial fibrillation, atrial flutter, premature atrial contractions, wandering atrial pacemakers, sinus bradycardia, sinoatrial arrest, sinoatrial outlet block, and sinus tachycardia. Hypersensitivity reactions to cardiac glycosides, though rare, can occur and usually appear within 6–10 days of starting treatment. Skin reactions may manifest as erythema or scarlet fever-like rashes. The rash may present as papules, vesicles, or bullae. The rash is usually accompanied by eosinophilia; eosinophilia may also occur without a skin reaction. Reports of urticaria, fever, itching, facial, angioedema, or laryngeal edema, hair loss, nail and toenail loss, and desquamation have been reported. Rarely, thrombocytopenic purpura has been reported during administration of cardiac glycosides (especially Digitoxin). Animal studies: Electrocardiographic monitoring of adult rats and 1-week-old rats during severe acute Digitoxin poisoning showed no cardiotoxicity despite significant neurotoxicity in both age groups. Elevated adrenal concentrations were observed in all animals.
Digitoxin inhibits the Na-K-ATPase membrane pump, leading to increased intracellular sodium and calcium concentrations. Increased intracellular calcium concentrations may promote the activation of contractile proteins such as actin and myosin. Digitoxin also acts on cardiac electrical activity, increasing the slope of phase 4 depolarization, shortening action potential duration, and reducing maximal diastolic potential.

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Interactions
Background: The cardiac glycoside Digitoxin preferentially inhibits the growth of breast cancer cells and targets the ERK pathway. Digitoxin alters the expression of IAP genes mediating calcium metabolism. Objective: Since combination therapy is the optimal treatment for cancer, we evaluated the growth-inhibiting effects of Digitoxin in combination with calcium metabolism inhibitors (such as the sarcoplasmic/endoplasmic reticulum Ca2+-ATPase inhibitor carotenoid) and the statin simvastatin, and the effect of Digitoxin on the IAP apoptosis pathway. Methods: To elucidate the signaling pathway, we treated human cancer cells with Digitoxin alone or in combination with carotenoid or simvastatin, and used MTT and colony formation assays to detect cell growth. We used histological and Western blot analyses of HEK293 cells to examine its effect on IAP. Results: Digitoxin inhibited the growth of breast, colon, and ovarian cancer cells. Consistent with its effect on calcium metabolism, Digitoxin showed a synergistic effect with carotenoid and simvastatin on ER-negative breast cancer cells. Digitoxin activated the expression of Erk pathway genes and inhibited IAP gene expression. The pan-caspase inhibitor zVAD-FMK failed to block the growth-inhibiting effect of Digitoxin on HEK293 cells, suggesting that Digitoxin may exert its effects through a caspase-independent apoptosis pathway. Furthermore, Digitoxin had no effect on the major anti-apoptotic protein XIAP. Conclusion: Digitoxin appears to exert its effects through the ERK and stress response pathways, warranting further investigation into its role in cancer prevention and treatment. Our results suggest potential safety risks in patients with heart disease taking Digitoxin and statins concurrently. PMID: 26691294
This review summarizes the effects of concomitant medication on the absorption, distribution, and excretion of Digitoxin and statins. Various drugs can increase or decrease the absorption of Digitoxin and statins in the gastrointestinal tract by altering gastrointestinal motility, physical adsorption of drugs, changes in intestinal wall properties, or alterations in gut microbiota. If the changes in absorption are sufficiently large, they may affect the steady-state serum concentrations of Digitoxin and statins, potentially requiring dose adjustments. Concomitant use of heparin and cardiac glycosides can lead to decreased protein binding rates of both Digitoxin and digitoxin. Since digitoxin has a higher protein binding rate than Digitoxin, interactions involving altered protein binding rates are of greater clinical significance for digitoxin. Many drugs can increase or decrease the clearance of both Digitoxin and digitoxin, resulting in cardiac glycoside concentrations below therapeutic levels or reaching toxic levels. Drugs that induce hepatic microsomal enzymes can increase digitoxin clearance, which is primarily cleared via hepatic biotransformation. Digitoxin is primarily cleared via renal excretion; vasodilators and thyroid hormones can increase renal clearance of Digitoxin, while quinidine, verapamil, amiodarone, and potassium-sparing diuretics can decrease it. The clinical significance of changes in serum cardiac glycoside concentrations due to altered glycoside clearance requires further investigation; preliminary reports on interactions between cardiac glycosides and diazepam, captopril, and quinidine-pentobarbital or quinidine-rifampin combinations also need further investigation. Because cardiac glycosides have a narrow therapeutic window, patients receiving concurrent treatment with drugs that may affect their absorption, distribution, or clearance should be closely monitored for signs of digitalis toxicity or undertreatment. PMID:2412751
Cholexenamine can accelerate the metabolism of Digitoxin… Chemical Society. Metabolism of Exogenous Compounds in Mammalians, Vol. 3. London: Chemical Society, 1975, pp. 101-101. 144. Hazardous Substances Database (HSDB) Cardiac glycoside toxicity can also lead to various atrial and sinoatrial node arrhythmias and conduction disorders, including atrial tachycardia, atrial fibrillation, atrial flutter, premature atrial contractions, wandering atrial pacemakers, sinus bradycardia, sinoatrial arrest, sinoatrial outlet block, and sinus tachycardia. Junctional premature contractions may also occur. Excessive bradycardia may be a sign of cardiac glycoside poisoning, but mild resting bradycardia may not require discontinuation of the glycoside if there are no other signs of poisoning. In patients with sinoatrial node disease (i.e., sick sinus syndrome), cardiac glycosides may worsen sinus bradycardia or sinoatrial block, especially when used in combination with other drugs that inhibit sinoatrial node or atrioventricular conduction (e.g., β-adrenergic blockers and certain non-dihydropyridine calcium channel blockers). /Cardioglycosides/

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Antidotes and Emergency Treatment
Digitoxin immune Fab fragments have been used to treat approximately 150 cases of life-threatening arrhythmias and/or hyperkalemia caused by Digitoxin or digitoxin poisoning in adults and children. In most cases, patients did not respond to conventional treatments including atropine, lidocaine (such as serocaine), and phenytoin sodium (such as diphenhydramine). Pharmacokinetic studies have shown that within one minute of intravenous injection of Digitoxin-immuno-Fab, the concentration of free Digitoxin or digitoxin in serum drops to undetectable levels (< 0.2 ng/mL). Favorable changes in heart rhythm or serum potassium concentration occur within 15 to 30 minutes. The antibody fragments and bound drug are primarily excreted via the kidneys; the elimination half-life in patients with normal renal function is approximately 15–20 hours. Excretion may be slower in patients with renal impairment. …Most patients experience resolution of toxic symptoms within hours. Deaths are primarily attributed to insufficient antibody fragment quantity or irreversible heart failure. Due to limited clinical application and the unclear effects of repeated administration, Digitoxin-immuno-Fab is not indicated for mild digitalis toxicity. It is recommended for patients with shock or cardiac arrest, or those with ventricular arrhythmias (such as ventricular tachycardia or ventricular fibrillation), progressive bradycardia, or second- or third-degree atrioventricular block unresponsive to atropine. Medical Communications 28 (722): 87-8 (1986)
Emergency and supportive measures. 1. Maintain a clear airway and provide assisted ventilation if necessary. 2. Due to the delayed tissue distribution of the drug, patients should be closely monitored for at least 12-24 hours after a large dose. 3. Use Digitoxin-specific antibodies to treat hyperkalemia; calcium (calcium gluconate 10%...sodium bicarbonate...and/or sodium polystyrene sulfonate (Kayexalate...). a. Note: Although it is widely recommended that calcium be avoided in hospitalized patients with cardiac glycoside poisoning due to concerns about exacerbating ventricular arrhythmias, this warning is based on old and very weak case reports and has not been confirmed by animal studies. Calcium is the first-line treatment for life-threatening cardiotoxicity caused by hyperkalemia. b. Mild hyperkalemia may actually have a protective effect against tachyarrhythmias. 4. Hypokalemia and hypomagnesemia should be corrected, as these can lead to cardiotoxicity. 5. Use atropine to treat bradycardia or heart block...For persistent symptomatic bradycardia, a temporary transvenous pacemaker may be necessary, but because pacemakers can cause serious arrhythmias in patients with digitalis poisoning, pacing therapy...is recommended only when Digitoxin-specific antibody treatment fails or is unavailable. 6. Ventricular tachycardia may be effective in correcting hypokalemia or hypomagnesemia. Lidocaine and phenytoin sodium have been used, but Digitoxin-specific antibodies are the first-line treatment for life-threatening arrhythmias. Avoid quinidine, procainamide, and other class 1a or 1c antiarrhythmic drugs. /Digitoxin and other cardiac glycosides/
Specific drugs and antidotes. Fab of Digitoxin-specific antibodies Fragments (such as DigiFab) can effectively reverse Digitoxin poisoning and are suitable for severe poisoning. This includes hyperkalemia (>mEq/L), symptomatic arrhythmias, high-degree atrioventricular block, ventricular arrhythmias, and hemodynamic instability. Digitoxin antibodies should also be considered for patients with Digitoxin poisoning and renal failure, as well as for patients requiring prophylactic treatment. Treatment is indicated for patients with large oral overdose and high serum concentrations. Digitoxin antibodies bind rapidly to Digitoxin and less to digitoxin and other cardiac glycosides. The inactive complex formed is rapidly excreted in the urine. .../Digitoxin and other cardiac glycosides/
Decontamination. If possible, activated charcoal can be administered orally. If activated charcoal is administered promptly, gastric lavage is not necessary after small to moderate doses. /Digitoxin and other cardiac glycosides/

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Human toxicity summary
/Signs and symptoms/ The toxic effects of cardiac glycosides that are excreted relatively quickly (e.g., Digitoxin) usually subside faster than those of cardiac glycosides that are excreted slowly (e.g., digitoxin). The toxicity of cardiac glycosides has a cumulative effect; when one cardiac glycoside causes toxicity, taking all other cardiac glycosides will exacerbate the toxicity. Contraindicated. Most cases of cardiac glycoside poisoning occur after multiple doses, at least in part due to the cumulative effect of the drugs. ... /Cardioglycosides/
/Signs and Symptoms/ Overdose of cardiac glycosides can present with a variety of signs and symptoms that are difficult to distinguish from symptoms associated with heart disease (e.g., gastrointestinal adverse reactions, arrhythmias). Before continuing treatment, an attempt should be made to determine whether these manifestations are caused by the cardiac glycoside. However, this can be difficult because symptoms of poisoning do not appear regularly, and subjective symptoms of poisoning in infants and young children are often more difficult to identify than in adults. /Cardioglycosides/
/Signs and Symptoms/ Extracardiac manifestations of cardiac glycoside poisoning are similar in both acute and chronic cases. However, gastrointestinal reactions, as well as milder central nervous system and visual symptoms, are more common in both acute and chronic poisoning. Disorders may be more pronounced after acute overdose. Acute poisoning can lead to hyperkalemia, while chronic poisoning may result in hypokalemia or normokalemia. Furthermore, patients on long-term cardiac glycoside treatment may also develop hyperkalemia, normokalemia, or hypokalemia if acute poisoning occurs. In pediatric patients, drowsiness and vomiting are usually the most prominent extracardiac adverse reactions. However, in children, life-threatening arrhythmias can occur suddenly even without signs of extracardiac poisoning. /Cardioglycosides/
/Signs and Symptoms/ Anorexia, nausea, and vomiting are common early symptoms of poisoning and may precede or follow cardiotoxicity symptoms. Gastrointestinal reactions may be at least partially mediated by the retromedullary region, as all routes of administration can cause gastrointestinal reactions. High doses of cardiac glycosides may also cause vomiting by directly stimulating the gastrointestinal tract. Nausea and vomiting may occur and cease suddenly. Other gastrointestinal reactions include salivation, upper or abdominal pain, bloating, diarrhea, constipation, and weight loss. Acute bleeding and necrosis of the intestines, esophagus, and stomach are rare occurrences in patients treated with cardiac glycosides. /Cardioglycosides/

[1]. Heart failure drug digitoxin induces calcium uptake into cells by forming transmembrane calcium channels . Proceedings of the National Academy of Sciences, 2008, 105(7): 2610-2615.

[2]. Anti-HSV activity of digitoxin and its possible mechanisms . Antiviral research, 2008, 79(1): 62-70.

[3]. Digitoxin inhibits HeLa cell growth through the induction of G2/M cell cycle arrest and apoptosis in vitro and in vivo . International Journal of Oncology, 2020, 57(2): 562-573.

[4]. Classical drug digitoxin inhibits influenza cytokine storm, with implications for COVID-19 therapy . in vivo, 2020, 34(6): 3723-3730.

[5]. Digitoxin is a potential anticancer agent for several types of cancer . Medical hypotheses, 1999, 53(6): 543-548.

Digitoxin is an odorless white or pale yellow microcrystalline powder used as a cardiac glycoside. (EPA, 1998)
Digitoxin is a cardiac glycoside whose 3β-hydroxyl group is linked to a 2,6-dideoxy-β-D-ribose-hexopyranosyl-(1→4)-2,6-dideoxy-β-D-ribose-hexopyranosyl-(1→4)-2,6-dideoxy-β-D-ribose-hexopyranosyl-(1→4)-2,6-dideoxy-β-D-ribose-hexopyranosyl-trisaccharide chain. It is an EC 3.6.3.9 (Na(+)/K(+)-transfer ATPase) inhibitor. Its function is related to the Digitoxin ligand; it is the conjugate acid of Digitoxin(1-).
Sometimes used as a substitute for Digitoxin. Its half-life is longer than Digitoxin; its toxicity is similar to Digitoxin, but lasts longer. (Excerpt from Martindale Pharmacopoeia, 30th Edition, p. 665)
Digitoxin has been reported to be detected in Foxtrorotatory violet, Foxtrorotatory macrocarpa, and other organisms with relevant data.
Digitoxin is a lipid-soluble cardiac glycoside that inhibits the plasma membrane sodium-potassium ATPase, leading to increased intracellular sodium and calcium ion levels and decreased potassium ion levels. Studies have shown that increased intracellular calcium ion levels precede cell death, while decreased intracellular potassium ion levels increase caspase activation and DNA fragmentation, thereby leading to apoptosis and inhibiting cancer cell growth. (National Cancer Institute, USA)
Digitoxin is only present in individuals who have used or taken the drug. It is a cardiac glycoside and is sometimes used as an alternative to Digitoxin. Its half-life is longer than Digitoxin; its toxic effects are similar to Digitoxin, but last longer. (Excerpt from Martindale Pharmacopoeia, 30th Edition, p. 665) Digitoxin inhibits the Na-K-ATPase membrane pump, leading to increased intracellular sodium and calcium ion concentrations. Increased intracellular calcium ion concentration may promote the activation of contractile proteins (such as actin and myosin). Digitoxin also acts on cardiac electrical activity, increasing the slope of phase 4 depolarization, shortening the action potential duration, and decreasing the maximum diastolic potential.
A cardiac glycoside, sometimes used as an alternative to Digitoxin. It has a longer half-life than Digitoxin; its toxicity is similar to Digitoxin, but lasts longer. (From Martindale Pharmacopoeia, 30th edition, p. 665)
See also: Acetyl Digitoxin (the active fraction of Digitoxin); Digitalis (note moved here).
Indications
For the treatment and control of congestive heart failure, arrhythmias, and heart failure.
Mechanism of Action
Digitoxin inhibits the Na-K-ATPase membrane pump, leading to increased intracellular sodium and calcium ion concentrations. Increased intracellular calcium ion concentration may promote the activation of contractile proteins (such as actin and myosin). Digitoxin also affects cardiac electrical activity, increasing the slope of phase 4 depolarization, shortening action potential duration, and reducing maximal diastolic potential.
Objective: Recent studies have shown that the proarrhythmic effects of cardiac glycosides (CGs) on Ca(2+) treatment in cardiomyocytes involve the generation of reactive oxygen species (ROS). However, the specific pathways of ROS generation and the subsequent downstream molecular events mediating CG-dependent arrhythmias remain to be elucidated. Methods and Results: We used pharmacological methods and genetically engineered mouse models to investigate the effects of Digitoxin (DGT) on Ca²⁺ treatment and ROS generation in cardiomyocytes. Cardiomyocytes isolated from NADPH oxidase type 2 deficient mice (NOX2KO) and transgenic mice overexpressing mitochondrial superoxide dismutase showed significantly enhanced tolerance to the proarrhythmic effects of DGT, specifically through the inhibition of DGT-dependent ROS and spontaneous Ca²⁺ waves (SCWs). Furthermore, DGT-induced mitochondrial membrane potential depolarization was also eliminated in NOX2KO cells. Inhibition of PI3K, PKC, and mitochondrial KATP channels all suppressed DGT-dependent ROS production, suggesting that these proteins are involved in NOX2 activation and mitochondrial ROS production, respectively. Western blot analysis showed elevated levels of oxidized CaMKII in DGT-treated wild-type (WT) hearts, but not in NOX2KO mouse hearts. In mouse cardiomyocytes constitutively inactivated at the Ser 2814 CaMKII phosphorylation site on RyR2, the DGT-induced increase in SCW frequency disappeared. Conclusion: These results indicate that the arrhythmogenic adverse effects of CGs on Ca(2+) treatment involve PI3K and PKC-mediated NOX2 stimulation and subsequent NOX2-dependent mitochondrial ROS release; mitochondrial-derived ROS then activate CaMKII, leading to RyR2 phosphorylation at Ser 2814. Endothelial cell-initiated pro-inflammatory processes are a key step in the pathogenesis of inflammatory cardiovascular diseases such as atherosclerosis. Recent observations suggest that the cardiac glycoside Digitoxin possesses potential anti-inflammatory properties. Therefore, this study investigated the potential anti-inflammatory and angiogenic protective effects of Digitoxin, as well as its influence on signaling pathways in endothelial cells (ECs). At commonly used therapeutic concentrations (3-30 nM), Digitoxin effectively inhibited IL-1β-induced expression of MCP-1 and VCAM-1 in ECs and suppressed the ability of the corresponding cell culture supernatant to promote monocyte migration and adhesion to endothelial monolayers. Furthermore, Digitoxin inhibited IL-1β-induced activation of p44/42-MAPK and NF-κB without affecting JNK and p38-MAPK activation. Inhibition of the NF-κB signaling pathway (but not p44/42-MAPK) mimicked Digitoxin's inhibitory effects on MCP-1 expression and monocyte migration. In addition, Digitoxin inhibited the NF-κB signaling pathway at the TAK-1/IKK level. Digitoxin also inhibited TNF-α-induced endothelial cell apoptosis by activating Akt. Blocking the Akt activator PI-3 kinase inhibits the anti-apoptotic effect of Digitoxin and weakens its inhibitory effect on the NF-κB signaling pathway and MCP-1 expression. Finally, Digitoxin activates endothelial nitric oxide synthase, and this activation is blocked by inhibition of PI-3 kinase, Ca²⁺/calmodulin-dependent protein kinase II, and intracellular calcium chelation. Digitoxin exerts anti-inflammatory and angiogenic effects in endothelial cells by blocking NF-κB and activating the PI-3 kinase/Akt signaling pathway and Ca²⁺/calmodulin-dependent protein kinase II. These observations suggest that Digitoxin has potential therapeutic value in treating cardiovascular diseases such as atherosclerosis. Cardiac glycosides have been used to treat arrhythmias for over 200 years. Two-pore domain (K2P) potassium channels regulate myocardial action potential repolarization. Recent studies have shown that K2P3.1 [the tandem P domain in the weakly inwardly rectifying potassium channel (TWIK)-associated acid-sensitive potassium channel (TASK)-1] is associated with the pathophysiological mechanisms of atrial fibrillation and is considered a selective antiarrhythmic drug target. We hypothesize that blocking cardiac K2P channels is one of the mechanisms by which Digitoxin exerts its effects. We screened all functional human K2P channels for interactions with cardiac glycosides. Human K2P channel subunits were expressed in Xenopus laevis oocytes, and K+ currents were recorded using voltage-clamp electrophysiology. Digitoxin significantly inhibited K2P3.1 and K2P16.1 channels. In contrast, Digitoxin only showed inhibitory effects on the K2P3.1 channel. The outward current of K2P3.1 was reduced by 80% (Digitoxin, 1 Hz) and 78% (Digitoxin, 1 Hz), respectively. The IC50 value of Digitoxin for K2P3.1 current was 7.4 μM. The outward rectifying properties of this channel were unaffected. Mutagenesis studies have shown that amino acid residues located on the cytoplasmic side of the K2P3.1 channel pore constitute part of the binding site of cardiac glycoside molecules. In summary, cardiac glycosides target human K2P channels. Digitoxin and digitoxin exert their antiarrhythmic effects by blocking atrial K2P3.1 repolarization currents, but their significance requires further verification through translational medicine and clinical research. Cardiac glycosides inhibit the activity of sodium-potassium activated ATPase (Na+-K+-ATPase), an enzyme essential for the active transport of sodium ions across the cardiomyocyte membrane. Inhibition of this enzyme in cardiomyocytes can enhance cardiac contractility, and it was previously thought that the benefits of cardiac glycosides in heart failure were mainly related to their positive inotropic effects. However, studies have shown that the benefits of cardiac glycosides may be partly related to enzyme inhibition in non-cardiac tissues. Inhibition of Na+-K+-ATPase in vagal afferent fibers can sensitize cardiac baroreceptors, potentially reducing sympathetic output from the central nervous system. Furthermore, cardiac glycosides reduce sodium reabsorption in the renal tubules by inhibiting Na+-K+-ATPase in the kidneys; this leads to increased sodium transport in the distal renal tubules, which in turn inhibits renin secretion. These observations suggest a hypothesis regarding the mechanism of action of cardiac glycosides in heart failure: their primary effect is to weaken the activation of the neurohormonal system, rather than through positive inotropic effects. Toxic doses of cardiac glycosides cause potassium efflux and sodium influx in the myocardium. The toxicity is partly due to intracellular potassium loss caused by Na+-K+-ATPase inhibition. At therapeutic doses, the positive inotropic effect of cardiac glycosides involves increased calcium ion influx into contractile proteins, thereby enhancing excitation-contraction coupling; the role of Na+-K+-ATPase in this effect remains controversial. Cardiac glycosides: Low concentrations of cardiac glycosides, including ouabain, Digitoxin, and digitoxin, can inhibit cancer cell growth without affecting Na+,K+-ATPase activity, but the mechanism of their anticancer effect is not fully elucidated. Volume-regulating anion channels (VRACs) play a fundamental role in maintaining cell volume and also function in cell death signaling pathways. This article reports the role of a cardiac glycoside-induced signaling pathway mediated by the interaction between Na+,K+-ATPase and VRAC in human cancer cells. Sub-micromolar concentrations of ouabain enhance VRAC currents while slowing cancer cell proliferation. Knockdown of the VRAC-specific inhibitor (DCPIB) and the key VRAC component (LRRC8A) eliminates the effect of ouabain; membrane microdomain disruption or NADPH oxidase inhibition also weakens its effect. Digitoxin and digitoxin also exhibit anti-proliferative effects against cancer cells at therapeutic concentrations, and these effects can be blocked by DCPIB. In the membrane microdomains of cancer cells, LRRC8A was found to co-immunoprecipitate with the Na+,K+-ATPase a1 subtype. These effects induced by ouabain were not observed in non-cancer cells. Therefore, cardiac glycosides are thought to interact with Na+,K+-ATPase, stimulating the production of reactive oxygen species, and they apparently also activate VRAC within the membrane microdomains, thereby producing an antiproliferative effect. Mechanism of Action: Digitoxin exerts its effects through multiple mechanisms: formation of transmembrane calcium channels (regulating intracellular calcium ions), inhibition of HSV DNA polymerase (blocking viral replication), and induction of cell cycle arrest/apoptosis in cancer cells by downregulating cyclin B1 [1,2,3]. Therapeutic Potential: Due to its selective cytotoxicity and cytokine modulation properties, it has been investigated in heart failure (its initial indication), antiviral therapy (HSV, influenza), and cancer (cervical cancer, lung cancer) [1,2,3,4,5].

C41H64O13

764.95

764.434

C, 64.38; H, 8.43; O, 27.19

71-63-6

Gitoxin;4562-36-1

441207

White to off-white solid powder

1.3±0.1 g/cm3

902.3±65.0 °C at 760 mmHg

240ºC (dec.)(lit.)

269.5±27.8 °C

0.0±0.6 mmHg at 25°C

1.594

2.44

5

13

7

54

1410

20

C[C@@H]1[C@H]([C@H](C[C@@H](O1)O[C@@H]2[C@H](O[C@H](C[C@@H]2O)O[C@@H]3[C@H](O[C@H](C[C@@H]3O)O[C@H]4CC[C@]5([C@@H](C4)CC[C@@H]6[C@@H]5CC[C@]7([C@@]6(CC[C@@H]7C8=CC(=O)OC8)O)C)C)C)C)O)O

WDJUZGPOPHTGOT-XUDUSOBPSA-N

InChI=1S/C41H64O13/c1-20-36(46)29(42)16-34(49-20)53-38-22(3)51-35(18-31(38)44)54-37-21(2)50-33(17-30(37)43)52-25-8-11-39(4)24(15-25)6-7-28-27(39)9-12-40(5)26(10-13-41(28,40)47)23-14-32(45)48-19-23/h14,20-22,24-31,33-38,42-44,46-47H,6-13,15-19H2,1-5H3/t20-,21-,22-,24-,25+,26-,27+,28-,29+,30+,31+,33+,34+,35+,36-,37-,38-,39+,40-,41+/m1/s1

3-[(3S,5R,8R,9S,10S,13R,14S,17R)-3-[(2R,4S,5S,6R)-5-[(2S,4S,5S,6R)-5-[(2S,4S,5S,6R)-4,5-dihydroxy-6-methyloxan-2-yl]oxy-4-hydroxy-6-methyloxan-2-yl]oxy-4-hydroxy-6-methyloxan-2-yl]oxy-14-hydroxy-10,13-dimethyl-1,2,3,4,5,6,7,8,9,11,12,15,16,17-tetradecahydrocyclopenta[a]phenanthren-17-yl]-2H-furan-5-one

NSC 7529; digitoxin; 71-63-6; Digitoxoside; Crystodigin; Digitoxinum; Unidigin; Digitophyllin; Carditoxin; NSC-7529; NSC7529; Carditalin;

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ~100 mg/mL (~130.73 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (3.27 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (3.27 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.5 mg/mL (3.27 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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 (Please use freshly prepared in vivo formulations for optimal results.)