Capstar for Dogs and Cats: Uses, Dosage and Side Effects

Veterinarians may recommend Capstar® for:

• Rapid elimination of adult fleas during an active infestation
• Temporary flea control before bathing, grooming, or veterinary procedures
• Immediate relief in pets with flea allergy dermatitis (as part of a larger treatment plan)
• Short-term flea control while transitioning to a long-acting flea preventive

Capstar® (nitenpyram) does not:

• Prevent future flea infestations
• Kill flea eggs or larvae
• Control ticks, mites, or internal parasites

Mechanism of action:

• Nitenpyram interferes with normal nerve signals in fleas
• This causes rapid nervous system overstimulation
• Fleas die within hours of exposure

Key points in cats:

• The onset of action is rapid
• Flea death can occur within hours
• The short duration allows repeat infestations to occur without additional flea control.

General principles:

• Dosing is strictly based on body weight
• Tablets should be swallowed whole
• Food is not required for absorption

Capstar® is approved for puppies 4 weeks of age and older.

• The puppy should have a minimum body weight of 2 pounds.
• Puppies should be clinically stable before dosing.

Small dogs are more vulnerable to dosing errors because of their size. Accurate weighing is essential. Only the tablet strength appropriate for the dog’s current weight should be used.

Medium-sized dogs generally tolerate Capstar® well. For dogs weighing 11-57 kg, the recommended dose is 1 large Capstar® tablet (57 mg). It can be given once daily, continued only until adult fleas are no longer found on the dog. Monitoring for temporary restlessness or increased scratching after dosing is advised.

Capstar® dosing in large dogs is based strictly on body weight. For dogs over 57 kg, use one 57 mg tablet or follow veterinary guidance for dosing. It should be administered only under veterinary advice. Do not split or combine tablets unless specifically instructed by a veterinarian.

Capstar® for cats is given orally as a tablet. Key guidance:

• Administer the whole tablet as directed
• Pet parents can hide the tablets in food if necessary. But make sure the cat swallows them.
• Repeat dosing should only be done under veterinary guidance

Side Effects of Capstar® in Dogs

• Approved for kittens 4 weeks of age and older
• Minimum weight requirement must be met (2 pounds or greater)
• Use cautiously in kittens with dehydration or systemic illness

Most dogs and cats tolerate Capstar® well. Reported side effects are usually mild and temporary.

Possible effects include:

• Increased scratching or restlessness (often due to dying fleas)
• Mild lethargy
• Temporary hyperactivity
• Decreased appetite
• Excessive drooling
• Rare allergic reactions (e.g., hives)
• Vomiting (uncommon)

Possible effects include:

• Transient restlessness
• Vocalization
• Increased grooming
• Mild gastrointestinal upset
• Fever (rare)
• Difficulty breathing (rare)

Overdose in dogs is uncommon but may result in:

• Excessive agitation
• Vomiting
• Tremors (rare)

Overdose in cats may result in:

• Marked agitation
• Vomiting
• Weakness

• Store at room temperature
• Keep tablets in original packaging
• Protect from moisture and heat
• Keep out of reach of pets and children
• Do not use expired tablets

Contact your veterinarian immediately if your pet shows:

• Persistent vomiting
• Tremors or seizures
• Severe lethargy
• Signs of allergic reaction (facial swelling, difficulty breathing)
• Repeated flea infestations despite treatment