Famotidine vs omeprazole for dogs: stomach acid reducers compared
Famotidine (Pepcid) and omeprazole (Prilosec) are human acid reducers vets prescribe for dogs and cats with stomach ulcers, gastritis or reflux. In studies in dogs, omeprazole suppressed acid more strongly; famotidine is gentler and simpler for short-term use.
Updated October 4, 2026
At a glance
- Strength
- Famotidine
- Moderate acid reduction
- Omeprazole
- Stronger, longer acid suppression
- How often
- Famotidine
- Once or twice a day
- Omeprazole
- Often twice a day
- Typical use
- Famotidine
- Mild stomach upset, short courses
- Omeprazole
- Ulcers, significant gastritis, reflux
- Giving it
- Famotidine
- Tablets can usually be split
- Omeprazole
- Delayed-release; do not crush unless your vet says
- Where to fill
- Famotidine
- Over the counter or a regular pharmacy
- Omeprazole
- Over the counter or a regular pharmacy
Famotidine Pepcid | Omeprazole Prilosec | |
|---|---|---|
| Strength | Moderate acid reduction | Stronger, longer acid suppression |
| How often | Once or twice a day | Often twice a day |
| Typical use | Mild stomach upset, short courses | Ulcers, significant gastritis, reflux |
| Giving it | Tablets can usually be split | Delayed-release; do not crush unless your vet says |
| Where to fill | Over the counter or a regular pharmacy | Over the counter or a regular pharmacy |
Which is used when
For ulcers or serious stomach inflammation, omeprazole is usually preferred because it reduces acid more effectively in dogs. Famotidine is often used for milder or short-term problems. Your vet will match the choice and dose to the cause.
Buying the right product
Use only plain famotidine or plain omeprazole. Combination products, such as versions with antacids or other ingredients, are not suitable, and liquids may contain sweeteners that are unsafe for pets. Ask your vet for the exact product and dose before buying over the counter.
Giving them
Both work best given before a meal. Omeprazole capsules and tablets are designed to survive stomach acid, so do not crush them unless your vet says to. After several weeks of omeprazole, your vet may taper it to avoid rebound acid.
See the vet first
Vomiting, black stools, not eating or a painful belly need diagnosis, because acid reducers can mask serious problems such as ulcers from anti-inflammatory medicines or swallowed objects.
Cost
Both are inexpensive human generics available over the counter or from a regular pharmacy.
With other medicines
Acid reducers can change how some other medicines are absorbed, so give them on the schedule your vet sets. If your dog takes an anti-inflammatory such as carprofen or meloxicam and starts vomiting or passing black stools, stop the anti-inflammatory and call your vet.
Questions for your vet
- Which acid reducer suits my pet’s problem?
- Which exact product and dose should I buy?
- How long should my pet take it?
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Sources
Written by the Script Unlock editorial team from the sources above. It is general information, not advice for you or your pet; your vet decides which medicine is right.
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.