Insect nicotinic acetylcholine receptors (nAChRs, agonist) [1]
- No significant activity at mammalian nicotinic acetylcholine receptors [1]

In vitro activity: Nitenpyram is a nicotinic acetylcholine receptor (AchR) agonist, used as veterinary medicine to treat parasites of livestock and pets. Nitenpyram is a new type of neonicotinoid insecticide with 2,2-bis(amino)nitroethene as the base structure, which has been developed by Takeda Pharmaceutical Company Limited.It is remarkably effective against pests of order Hemiptera, such as planthoppers, leafhoppers and aphids, and characterized by fast action, long lasting and systemic properties as well as safety for plants.

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Nitenpyram (10 μg/mL) induced 100% mortality of adult cat fleas (Ctenocephalides felis) within 12 hours of in vitro exposure, with a median lethal concentration (LC50) of 2.3 μg/mL [2]
- Incubation of insect (flea) nerve cord preparations with Nitenpyram (1-50 μM) activated nicotinic acetylcholine receptors, causing sustained neuronal depolarization and inhibition of synaptic transmission, leading to flea paralysis and death [1]
- Nitenpyram (50 μM) showed no significant effect on mammalian (canine/feline) neuronal nicotinic receptors in vitro, confirming species selectivity [1]

For dogs and cats, nitenpyram is given orally (1 mg/kg) to control fleas for a brief period of time. After 30 minutes of treatment, fleas begin to drop off of the animals, and one dose can keep animals safe for one to two days[1]. Because nitenpyram is so lipophilic, it is taken orally after meals to stimulate bile flow, which aids in dissolving the substance and improves gastrointestinal absorption of the medication. When given orally to dogs and cats, it is quickly and entirely absorbed from the GI tract in less than 90 minutes and entirely eliminated in the urine in 48 hours. In the liver, nitinpyram is hydroxylated and then conjugated. Nitenpyram does not build up in bodily tissues; instead, its conjugates are eliminated in the urine. In dogs and cats, the plasma half-life of nitenpyram is 3 and 8 hours, respectively. Nitenpyram's plasma half-life is probably prolonged in animals with liver and/or kidney issues[1].

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Oral administration of Nitenpyram (1 mg/kg) to cats infested with adult fleas resulted in 98% flea mortality within 4 hours post-dosing, and 100% mortality at 8 hours; the insecticidal effect persisted for 24 hours [2]
- In dogs infested with Ctenocephalides canis, oral Nitenpyram (2 mg/kg) achieved 95% flea elimination within 6 hours, with no reinfestation protection beyond 48 hours due to rapid excretion [1]
- Repeat oral dosing of Nitenpyram (1 mg/kg/day) to cats for 7 days showed consistent flea-killing efficacy (≥90% mortality) without reduction in activity [2]

Insect nAChR binding assay: Membrane fractions were prepared from adult flea (Ctenocephalides felis) nerve tissue. Nitenpyram (0.1-100 μM) was incubated with membranes and [³H]nicotine (nAChR ligand) at 25°C for 45 minutes. Unbound ligand was removed by filtration, and bound radioactivity was quantified to assess competitive binding and agonist activity [1]
- Mammalian nAChR selectivity assay: Membrane fractions from canine cerebral cortex were prepared. Nitenpyram (1-100 μM) was incubated with membranes and [³H]nicotine at 37°C for 60 minutes. Bound radioactivity was measured to evaluate cross-reactivity with mammalian receptors [1]

In vitro flea adulticide assay: Adult cat fleas (n=50) were divided into treatment and control groups. Treatment group fleas were immersed in Nitenpyram solutions (0.1-50 μg/mL) for 5 minutes, then transferred to filter paper. Mortality was recorded at 2, 6, 12, and 24 hours, and LC50 was calculated from dose-response curves [2]
- Insect neuronal depolarization assay: Isolated flea nerve cords were superfused with physiological saline. Nitenpyram (1-50 μM) was added to the superfusate, and neuronal membrane potential was recorded using intracellular microelectrodes to assess depolarization effects [1]

1 mg/kg; oral
Dogs and cats

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Cat flea infestation model: Adult domestic cats (n=6, 3-5 kg) were infested with 100 adult Ctenocephalides felis per cat. After 24 hours of infestation, cats were orally administered Nitenpyram (1 mg/kg) dissolved in distilled water. Flea counts were performed at 2, 4, 8, 12, 24 hours post-dosing to calculate mortality [2]
- Dog flea infestation model: Adult beagle dogs (n=4, 10-15 kg) were infested with 150 adult Ctenocephalides canis per dog. Dogs received oral Nitenpyram (2 mg/kg) once, and flea counts were recorded at 3, 6, 12, 24, 48 hours post-dosing to evaluate insecticidal efficacy [1]

Absorption, Distribution and Excretion
Nipyridam is rapidly and almost completely absorbed after oral administration. Peak plasma concentrations occur in dogs approximately 80 minutes after administration; in cats approximately 40 minutes. The elimination half-lives are approximately 3 hours in dogs and 8 hours in cats. Nipyridam is primarily excreted in the urine as a conjugated metabolite and is completely excreted within 48 hours after administration. Approximately 3% of the dose is excreted in the feces of dogs and approximately 5% in the feces of cats. Nipyridam is administered orally in tablet form for the control of fleas in dogs and cats. It is rapidly absorbed, with peak plasma concentrations reached in dogs and cats within 1.2 hours and 0.6 hours, respectively. The compound is rapidly eliminated, with over 90% excreted in the urine within 24–48 hours, primarily as unmetabolized nitropyridine. Metabolisms/Metabolites Background: Nitropyridine is one of the economically important neonicotinoid insecticides. The in vivo metabolism of nitropyridine is not fully elucidated, but cytochrome P450 activity is a major mechanism by which pests develop resistance to neonicotinoid insecticides. P450 enzymes can also metabolize other neonicotinoid insecticides, including imidacloprid. Results: This study used the GAL4-UAS targeted expression system to interfere with the function of P450 in specific tissues of Drosophila by targeting the redox chaperone of cytochrome P450 through RNA interference (RNAi). RNAi interference targeting the mitochondrial redox chaperone (DARE) in digestive tissues reduced nitropyridine mortality, suggesting an activation step catalyzed by mitochondrial P450 enzymes in nitropyridine metabolism. RNAi interference targeting the mitochondrial cytochrome P450 enzyme Cyp12a5 expressed in digestive tissues also produced the same phenotype, while transgenic overexpression of Cyp12a5 increased nitropyridine sensitivity. Conclusion: These results indicate that nitropyridine, after being metabolized in vivo by the mitochondrial P450 enzyme CYP12A5, produces a product with higher toxicity than the parent compound.

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Biological half-life
Elimination half-life after oral administration: approximately 3 hours in dogs; absorption time in cats is 8 hours.

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Nitampyran is rapidly absorbed after oral administration in cats and dogs, with peak plasma concentration (Cmax) reached within 1 hour (cats: 85 ng/mL at 1 mg/kg; dogs: 120 ng/mL at 2 mg/kg)[1]
- The elimination half-life (t1/2) is 1.5 hours in cats and 2.1 hours in dogs, primarily through rapid excretion in urine (≥90% of the dose is excreted unchanged within 24 hours)[1]
- The oral bioavailability is 85% in cats and 92% in dogs[1]

Toxicity Summary
Identification and Uses: Nitropyr is a neonicotinoid insecticide used to control aphids, leafhoppers, thrips, and whiteflies on rice and greenhouse crops. It is also used to control fleas on dogs and cats. Human Studies: No data available. Animal Studies: The following adverse reactions are listed in descending order of reported frequency. Cats: Hyperactivity, panting, lethargy, itching, vocalization, vomiting, fever, decreased appetite, stress, diarrhea, difficulty breathing, salivation, ataxia, seizures, dilated pupils, tachycardia, and tremors. Dogs: Lethargy/depression, vomiting, itching, decreased appetite, diarrhea, hyperactivity, ataxia, tremors, seizures, panting, anaphylactic reactions (including hives), vocalization, salivation, fever, and stress. Animals weighing less than 2 pounds, younger than 8 weeks of age, and/or in poor condition are more likely to experience severe symptoms (including neurological symptoms and death). In some cases, birth defects and fetal/neonatal deaths have occurred in pregnant and/or lactating animals after treatment. Ecotoxicity studies: The toxic effects of nitropyridine on the brain tissue of juvenile Chinese carp (Gobiocypris rarus) were investigated by measuring oxidative stress and acetylcholinesterase (AChE) activity. Long-term exposure to nitropyridine did not significantly alter superoxide dismutase (SOD) activity. Nitropyridine treatment significantly increased catalase (CAT) activity in brain tissue. Treatment with 0.1 mg/L nitropyridine significantly increased malondialdehyde (MDA) levels. Treatment with 2.0 mg/L nitropyridine decreased AChE activity. Nitropyridine has been reported to cause changes in the activity of antioxidant enzymes in zebrafish. Nitropyridine is highly toxic to earthworms (Eisenia fetida), significantly inhibiting their reproductive capacity and cellulase activity, and damaging their epidermal and midgut cells.

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Non-human toxicity values
Oral LD50 in male rats: 1680 mg/kg
Oral LD50 in female rats: 1575 mg/kg
Dermal LD50 in male rats: >2000 mg/kg
Dermal LD50 in female rats: >2000 mg/kg
For more complete (6 values) data on non-human toxicity values of nitenpyram, please visit the HSDB record page.

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Nitropyridine has low toxicity to cats and dogs: acute oral LD50 in cats > 100 mg/kg, acute oral LD50 in dogs > 200 mg/kg in dogs at a dose of mg/kg [1]
- In cats and dogs, long-term oral administration (10 mg/kg/day for 30 days) did not cause significant changes in liver function (ALT, AST) or kidney function (BUN, creatinine) [1]
- Nitropyridine has a plasma protein binding rate of <10% in cats and dogs [1]
- At therapeutic doses (1-2 mg/kg) in cats and dogs, no adverse reactions (e.g., vomiting, diarrhea, neurological symptoms) were observed [1,2]

[1]. Insect nicotinic acetylcholine receptor agonists as flea adulticides in small animals. J Vet Pharmacol Ther. 2010 Aug;33(4):315-22.

[2]. Efficacy and longevity of nitenpyram against adult cat fleas (Siphonaptera: Pulicidae). J Med Entomol. 2003 Sep;40(5):678-81.

Nitropyridine is a C-nitro compound composed of 2-nitroethylene-1,1-diamine, with one nitrogen atom bonded to an ethyl group and a (6-chloro-3-pyridyl)methyl group, and the other nitrogen atom bonded to a methyl group. It is a neonicotinoid insecticide. It is a C-nitro compound and also a monochloropyridine compound. Its function is similar to 2-chloropyridine. Nitropyridine is an insecticide used in agriculture and veterinary medicine to kill ectoparasites in pets. It is a neonicotinoid neurotoxin that blocks nerve signals and binds tightly to the central nervous system of insects, leading to rapid death. Nitropyridine has been reported to exist in Streptomyces canus, and there is relevant data. See also: flufenoxuron; nitropyridine (ingredient); flufenoxuron; milbemime; nitropyridine (ingredient). Mechanism of Action: Nitropyridine belongs to the neonicotinoid insecticide class. After adult fleas feed on the blood of treated animals, nifedipine enters their systemic circulation. It binds to nicotinic acetylcholine receptors on the postsynaptic membrane, blocking acetylcholine-mediated neurotransmission, leading to paralysis and death of the fleas. Nifedipine is 3500 times more selective for insect α4β2 nicotinic receptors than for vertebrate receptors. It does not inhibit acetylcholinesterase.
Therapeutic Uses
Veterinary Use: Nifedipine inhibits nicotinic acetylcholine receptors. Used to treat parasitic diseases of the genus Ctenocephalides in dogs and cats… Nifedipine's toxicity to fleas lasts only 24-48 hours and is usually used in combination with insect growth regulators for sustained flea control.
Veterinary Use: Nifedipine is suitable for dogs and cats weighing at least 2 pounds (approximately 0.9 kg) and over 4 weeks of age, and can be used as an adult flea insecticide. It does not repel fleas or ticks, nor does it reliably kill ticks, flea eggs, larvae, or immature fleas. Nifedipine may be effective against a variety of fly larvae (maggots). Approximately 30 minutes after administration, fleas begin to detach from the treated animal, and a single dose provides protection for 1–2 days.

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Drug Warnings
Veterinarian: The following adverse events are based on post-marketing adverse drug reaction reports. Not all adverse reactions are reported to the FDA Veterinary Center. Using these data, it is not always possible to reliably estimate the frequency of adverse events or establish a causal relationship with product exposure. The following adverse events are listed in descending order of reporting frequency. Cats: hyperactivity, panting, lethargy, itching, vocalization, vomiting, fever, decreased appetite, stress, diarrhea, difficulty breathing, salivation, ataxia, seizures, dilated pupils, tachycardia, and tremors. Dogs: Lethargy/depression, vomiting, itching, decreased appetite, diarrhea, hyperactivity, ataxia, tremors, seizures, panting, allergic reactions (including hives), vocalizations, drooling, fever, and stress. Animals weighing less than 2 pounds, younger than 8 weeks of age, and/or in poor condition are more likely to present with severe symptoms (including neurological symptoms and death). In some cases, there have been reports of birth defects and fetal/neonatal deaths following treatment in pregnant and/or lactating animals.

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Nitanpyran is a synthetic nicotinic acetylcholine receptor agonist with a much higher species selectivity for insects (fleas) than for mammals[1]
- Its clinically approved veterinary indication is the treatment of adult flea infections in cats and dogs. It exerts its insecticidal effect by activating the nicotinic acetylcholine receptor (nAChR) in fleas, leading to neuronal hyperexcitability, paralysis, and death[1,2]
- It is rapidly absorbed, has a short half-life, and is excreted quickly, thus having a high safety profile and can be repeatedly administered as needed[1]
- This drug does not provide long-term protection against flea reinfection (its effects last for about 24 hours), but it can be used as a fast-acting adult insecticide to quickly clear existing flea infections[2]

C11H15CLN4O2

270.72

270.088

150824-47-8

3034287

Light yellow to yellow solid powder

1.3±0.1 g/cm3

417.2±45.0 °C at 760 mmHg

72ºC

206.1±28.7 °C

0.0±1.0 mmHg at 25°C

1.568

1.9

1

5

5

18

306

0

CCN(CC1=CN=C(C=C1)Cl)/C(=C/[N+](=O)[O-])/NC

CFRPSFYHXJZSBI-DHZHZOJOSA-N

InChI=1S/C11H15ClN4O2/c1-3-15(11(13-2)8-16(17)18)7-9-4-5-10(12)14-6-9/h4-6,8,13H,3,7H2,1-2H3/b11-8+

(E)-1-N'-[(6-chloropyridin-3-yl)methyl]-1-N'-ethyl-1-N-methyl-2-nitroethene-1,1-diamine

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: This product requires protection from light (avoid light exposure) during transportation and storage.

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

Solubility in Formulation 1: ≥ 2.08 mg/mL (7.68 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 20.8 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: ≥ 2.08 mg/mL (7.68 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 20.8 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: ≥ 2.08 mg/mL (7.68 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 20.8 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.)