Metronidazole
Flagyl (human) · generic metronidazole
Metronidazole is the antibiotic vets prescribe most often for diarrhoea, inflammatory bowel disease, Giardia and anaerobic infections in dogs and cats. It is a human generic that any pharmacy can fill, and it is famously bitter, which shapes how cats are given it.
What it is used for
Metronidazole works against anaerobic bacteria and some protozoa, and has an anti-inflammatory effect in the gut, which is why it has long been a first reach for acute diarrhoea in dogs. Current veterinary thinking uses it more selectively, for Giardia, confirmed anaerobic infections and inflammatory bowel disease, rather than for every bout of loose stool, and vets increasingly try diet and probiotics first.
Courses are short for infections and longer for inflammatory bowel disease. The human tablets are the standard product; the vet prescribes a dose by weight. Vomiting, reduced appetite and drooling from the bitter taste are common.
Safety points that differ from human use
- High doses or long courses can cause neurological signs: wobbliness, head tilt, abnormal eye movements, seizures. Stop and call the vet if any appear; they usually resolve when the drug is stopped.
- The tablets are intensely bitter; crushing them or opening capsules causes foaming and drooling in cats. A compounded flavoured liquid or a capsule swallowed whole avoids it.
- It is avoided in pregnancy and in very young animals.
- Tablets (human)
- Capsules (human)
- Compounded flavoured liquids and capsules for cats
- 250 and 500 mg tablets
- 375 mg capsules
- Compounded strengths to the vet’s prescription
Why the cash price varies
Metronidazole tablets are a commodity generic and a course costs pharmacies very little; the cash price is dispensing fee and margin. Compounded liquids for cats are made to order and vary by compounder. The benzoate form made by compounders is less bitter and is a separate product.
How to pay less
- For a dog, ask the vet for a human tablet strength that fits the dose.
- For a cat, ask whether a whole capsule or a small tablet is practical before paying for compounding.
- Ask whether metronidazole is on the pharmacy’s flat-price generic list.
- Upload the prescription to Script Unlock so licensed pharmacies, including compounders, can quote. You pay the pharmacy directly.
Questions for your vet
- What is this treating, and how long is the course?
- What neurological signs should make me stop and call?
- How do I give it to my cat without the bitterness?
- Should I give it with food?
- Is there a diet or probiotic plan alongside it?
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 metronidazole 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 metronidazole 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
- ASPCA Animal Poison Control
- FDA Orange Book (approved generics and therapeutic equivalence)
- MedlinePlus drug information (National Library of Medicine)
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.