Nitenpyram
(E)-Nitenpyram
Also known as: Capstar · Program · Bestguard · Bob Martin Flea Tablets · Johnson's 4 Fleas · TI-304 · (E)-Nitenpyram
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Flea adulticide (2-25 lb / 0.9-11.36 kg) | Give one 11.4 mg tablet PO. May be given as often as once per day. | PO | q24h | — | 🌎 NA |
| Flea adulticide (25-125 lb / 11.36-56.8 kg) | Give one 57 mg tablet PO. May be given as often as once per day. | PO | q24h | — | 🌎 NA |
| Flea infestation | 1 mg/kg (minimum) | PO | prn (can be given daily if needed) | As needed | 🌍 EU |
- Flea adulticide (2-25 lb / 0.9-11.36 kg): May be given with or without food.
- Flea adulticide (25-125 lb / 11.36-56.8 kg): May be given with or without food.
- Flea infestation: 11.4 mg tablet for dogs 1-11 kg; 57 mg tablet for dogs >11 kg
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Flea adulticide (2-25 lb / 0.9-11.36 kg) | Give one 11.4 mg tablet PO. May be given as often as once per day. | PO | q24h | — | 🌎 NA |
| Flea infestation | 1 mg/kg (minimum) | PO | prn (can be given daily if needed) | As needed | 🌍 EU |
- Flea adulticide (2-25 lb / 0.9-11.36 kg): May be given with or without food.
- Flea infestation: 11.4 mg tablet for cats 1-11 kg
Reptiles
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Maggots | crush one 11.4 mg tablet into powder and give PO, as an enema, or on wound one time. | PO/Rectal/Topical | one time | 1 dose | 🌎 NA |
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Nitenpyram is a fast-acting, systemic, oral neonicotinoid insecticide primarily used for the rapid knockdown of adult fleas (Ctenocephalides felis) on dogs and cats.
Clinical Pearls:
- It has an exceptionally rapid onset of action (fleas begin falling off the host within 30 minutes) but lacks residual activity (duration of effect is only 24-48 hours).
- Because it does not kill flea eggs, larvae, or immature forms, it is highly effective for acute flea infestations but must be combined with an insect growth regulator (IGR) or a long-acting adulticide for comprehensive flea control.
- Off-label use includes the treatment of myiasis (maggots) in various species, including reptiles.
Mechanism of action
Nitenpyram acts as an agonist at insect-specific nicotinic acetylcholine receptors (nAChRs).
- Ingestion by flea via blood meal → Binds to alpha-4-beta-2 nicotinic receptors on postsynaptic membranes → Blocks acetylcholine-mediated neuronal transmission → Continuous nerve firing → Spastic paralysis and rapid death of the insect.
- It is highly selective (3500 times more selective for insect receptors than vertebrate receptors) and does not inhibit acetylcholinesterase, contributing to its exceptionally high safety margin in mammals.
Safety & warnings
Contraindications
- Animals under 2 pounds of body weight
- Animals under 4 weeks of age
- Animals weighing less than 1 kg
Adverse effects
- Transient pruritus (scratching) due to dying fleas
- Transient pruritus (scratching/itching) as fleas die
- Vomiting (rare)
- Lethargy (rare)
- Panting or vocalization (rare, secondary to flea death)
Precautions
Not labeled to be used in animals under 2 pounds of body weight or under 4 weeks of age. Probably safe to use in breeding, pregnant, or lactating animals.
Monitoring
- Efficacy (flea knockdown)
- Resolution of flea infestation
- Adverse reactions (excessive scratching, vomiting)
Pharmacokinetics
Half-life
Absorption
Rapidly and practically completely absorbed after oral administration. Peak levels occur about 80 minutes after dosing in dogs; about 40 minutes in cats.
Distribution
Enters the systemic circulation and is consumed by adult fleas during a blood meal.
Metabolism
Minimal metabolism.
Elimination
Excreted primarily unchanged in the urine. In dogs, about 3% of a dose is excreted in the feces; in cats about 5% is excreted in the feces.
Overdose
Nitenpyram is relatively safe in high dosages to mammals.
- The oral LD50 in rats is approximately 1.6 grams/kg.
- Cats or dogs given 10 times the usual dose for 14 days showed no untoward effects.
- In the circumstance of a massive overdose, contact an animal poison control center for additional guidance.
Available products
Formulations
- Oral tablets
- 11.4 mg oral tablet
- 57 mg oral tablet
Veterinary
- Nitenpyram Oral Tablets: 11.4 mg and 57 mg in boxes containing blister packs of 6 tablets; Capstar (Novartis)
- Combination packs with Lufenuron (Program Flavor Tabs and Capstar Flea Management System)
- Combination with milbemycin and lufenuron (Sentinel Flavor Tabs and Capstar Flea Management System)
- Bob Martin Flea Tablets 11.4 mg, 57 mg
- Capstar 11.4 mg, 57 mg
- Johnson's 4 Fleas 11.4 mg, 57 mg
Regulatory status
Authorised Veterinary Medicine - General Sales List
No regulatory data for: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Commercially available nitenpyram tablets should be stored at room temperature (15-30°C; 59-86°F). Shelf life is reported to be 3 years if stored below 25°C (76°F).
Client information
Important Note: This medication kills adult fleas very quickly but does not kill flea eggs or larvae. It is usually used in combination with other products (like insect growth regulators) that will control those immature forms of fleas.
- You may notice your pet scratching frantically for a short period after giving the pill. This is a normal, temporary reaction caused by the fleas moving erratically as they die, not a side effect of the medication itself.
- Best dosed after a meal to increase absorption, though it can be given with or without food.
- All animals in the household should be treated simultaneously to prevent re-infestation.
- Keep tablets out of reach of children.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.