Amantadine
generic amantadine (human)
Amantadine is a human drug that vets add to an anti-inflammatory or gabapentin for dogs and cats with chronic pain that has become amplified in the nervous system, typically long-standing arthritis or cancer pain. It is a generic that any pharmacy can fill, and the capsule and the liquid are priced very differently.
What it is used for
Amantadine blocks NMDA receptors in the spinal cord and brain, the pathway through which long-standing pain becomes more intense over time, a process called wind-up. It does little for pain on its own but makes other painkillers work better, so vets add it to an NSAID or gabapentin for dogs with osteoarthritis that is no longer controlled, for cancer pain and after some surgeries. It is given once or twice a day and takes a week or two to show an effect.
In people amantadine is an old antiviral and Parkinson’s drug; in animals the use is off-label and the dose is set by weight. Agitation, diarrhoea and flatulence are the reported effects, and the dose is reduced in animals with poor kidney function.
Safety points that differ from human use
- Do not stop other pain medicines when amantadine is added; it is an add-on, not a replacement.
- Doses are reduced in kidney disease; tell the vet about any recent blood tests.
- Human amantadine liquid may contain sweeteners; have the pharmacist check it for xylitol before giving it to a dog.
- Capsules (human)
- Tablets (human)
- Oral solution (human; check sweeteners)
- Compounded small capsules for cats
- 100 mg capsules and tablets
- Oral solution 50 mg per 5 mL
Why the cash price varies
Amantadine capsules are a cheap generic; the oral solution costs pharmacies several times more and a large dog on a liquid dose uses a lot of it. A prescription for capsules at a strength that fits the dose is almost always the cheaper route. Not every pharmacy keeps it in stock.
How to pay less
- Ask the vet whether capsules would fit your dog’s dose rather than the liquid.
- Ask whether amantadine is on the pharmacy’s flat-price generic list, and compare a second pharmacy if it must be ordered.
- For long-term use, ask for a ninety-day prescription.
- Upload the prescription to Script Unlock so licensed pharmacies can quote. You pay the pharmacy directly.
Questions for your vet
- What is amantadine adding to my pet’s current pain plan?
- Capsules or liquid, and if liquid, is it free of xylitol?
- How long before we judge whether it helps?
- Does my pet’s kidney function change the dose?
- What side effects should I watch for?
Rules on refills, transfers and controlled substances differ by state; see pharmacy rules by state.
How Script Unlock gets you a cash price for your pet’s amantadine prescription
Prices on this site come from pharmacies responding to a real prescription. We do not publish estimated, average or "typical" prices, because none of those would be your price.
- 1You upload your prescription
A photo of your your pet’s amantadine prescription prescription is enough. Nothing is sold on the site; you are asking pharmacies to quote.
- 2Licensed pharmacies respond
Pharmacies that Script Unlock has verified see the request and each can reply with its own cash price for your exact drug, strength and quantity.
- 3You choose and pay the pharmacy
You compare the responses, pick a pharmacy, and pay that pharmacy directly when you collect. Script Unlock never takes a patient payment and never sets the price.
Related pet medications
Sources
- Merck Veterinary Manual
- FDA Orange Book (approved generics and therapeutic equivalence)
- MedlinePlus drug information (National Library of Medicine)
- ASPCA Animal Poison Control
Written by the Script Unlock editorial team from the sources above. Not yet reviewed by a veterinarian or veterinary pharmacist. Last checked 2026-10-03. Nothing here replaces your vet\u2019s directions; doses for animals are set by weight and species.
Script Unlock is a marketplace that lets licensed pharmacies quote a cash price on your prescription. It does not prescribe, dispense or sell medication, does not process patient payments, and does not give medical advice. Always follow the instructions of your prescriber and pharmacist and read the medication guide supplied with your medicine.