Dog Medication Dosage Calculator
Calculate common over-the-counter medication doses for your dog based on body weight. Includes Benadryl, Pepcid AC, Imodium, aspirin, melatonin, and emergency hydrogen peroxide dosing — with warnings, contraindications, and form guides.
Medication Dosage Calculator
Calculate common OTC medication doses for dogs by weight. Always confirm with your veterinarian before giving any medication.
⚠️ Important
This calculator provides standard veterinary reference ranges — not a prescription. Always consult your veterinarian before giving any medication. Some medications are dangerous for certain breeds, ages, or health conditions.
Your dog's weight
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Medications that are NEVER safe for dogs
Ibuprofen (Advil, Motrin)
Causes kidney failure and GI ulcers — even one dose
Naproxen (Aleve)
Same risks as ibuprofen but longer-acting — even more dangerous
Acetaminophen (Tylenol)
Toxic to liver. Especially dangerous for small dogs. Fatal for cats.
Pseudoephedrine (Sudafed)
Causes hyperactivity, seizures, rapid heart rate — potentially fatal
Sleep aids with xylitol
Xylitol is extremely toxic — causes seizures and liver failure within minutes
Disclaimer: This calculator provides standard veterinary reference ranges for informational purposes only. It is not a substitute for veterinary advice. Dosing can vary based on your dog's breed, age, health conditions, and other medications. Always consult your veterinarian before administering any medication.
In an emergency, call the ASPCA Animal Poison Control Center: 888-426-4435 or the Pet Poison Helpline: 855-764-7661.
Medication safety for dogs
The golden rule: not all human meds are safe for dogs
Dogs metabolize drugs differently than humans. What's safe for us can be fatal for them. The most important rule: never give your dog ibuprofen (Advil), naproxen (Aleve), or acetaminophen (Tylenol). Even a single dose of ibuprofen can cause kidney failure or fatal GI bleeding in dogs. Acetaminophen destroys red blood cells and damages the liver.
Breed-specific drug sensitivities
The MDR1 (ABCB1) gene mutation affects approximately 75% of Collies, 50% of Australian Shepherds, and significant percentages of other herding breeds. Dogs with this mutation cannot properly clear certain drugs from the brain, leading to neurotoxicity. Affected medications include loperamide (Imodium), ivermectin (at high doses), and several chemotherapy drugs. Testing is available through veterinary genetics labs.
| Medication | Standard dose | Key warning |
|---|---|---|
| Benadryl | 1–2 mg/kg | Use ONLY plain diphenhydramine — no Benadryl-D, no combination products |
| Pepcid AC | 0.5–1 mg/kg | Use ONLY plain famotidine — not Pepcid Complete (contains calcium carbonate + magnesium) |
| Cerenia | 2–8 mg/kg | PRESCRIPTION ONLY — requires veterinary authorization |
| Imodium | 0.08–0.1 mg/kg | DANGEROUS for herding breeds (Collies, Shelties, Aussies, Border Collies) — MDR1 gene mutation |
| Aspirin (buffered) | 5–10 mg/kg | Short-term use ONLY — GI ulcers develop quickly in dogs |
| Melatonin | 0.1–0.2 mg/kg | Check label — MUST NOT contain xylitol (common in chewable forms) |
| Hydrogen Peroxide 3% | 1–2 mL/kg | ONLY use when directed by a veterinarian or poison control |
Medication dosage FAQs
How much Benadryl can I give my dog?
The standard veterinary dose for Benadryl (diphenhydramine) in dogs is 1-2 mg per kg of body weight (approximately 1 mg per pound), given every 8-12 hours. For a 50-lb dog, that's 25-50 mg per dose (1-2 standard 25mg tablets). IMPORTANT: Use ONLY plain Benadryl — not Benadryl-D or any combination product. Avoid liquid formulas as many contain xylitol, which is toxic to dogs. Benadryl may cause drowsiness — this is normal and usually desired for allergic reactions.
Can I give my dog human medications?
Some human medications are safe for dogs at veterinary-approved doses (Benadryl, Pepcid AC, buffered aspirin short-term). However, many common human medications are TOXIC to dogs — including ibuprofen (Advil/Motrin), naproxen (Aleve), acetaminophen (Tylenol), and pseudoephedrine (Sudafed). Never assume a medication safe for humans is safe for dogs. Always confirm with your veterinarian before giving any medication, even over-the-counter ones.
What can I give my dog for pain?
The only OTC pain reliever sometimes recommended for short-term use in dogs is buffered aspirin (5-10 mg/kg, every 12 hours, with food, for no more than 3-5 days). However, veterinary-prescribed NSAIDs like carprofen (Rimadyl) or meloxicam (Metacam) are much safer for dogs. NEVER give ibuprofen, naproxen, or acetaminophen — these can cause fatal kidney failure, GI bleeding, or liver damage in dogs. If your dog is in pain, a vet visit is the safest approach.
How do I induce vomiting in a dog?
ONLY induce vomiting when directed by a veterinarian or poison control. Use 3% hydrogen peroxide: 1-2 mL per kg (about 1 teaspoon per 5 lbs), up to a maximum of 45 mL total. Give by syringe into the side of the mouth. Walk the dog afterwards to encourage vomiting. If no vomiting within 15 minutes, you may repeat ONCE. NEVER induce vomiting for caustic substances, sharp objects, petroleum products, or if the dog is unconscious or seizing. Call ASPCA Poison Control (888-426-4435) first.
Why are some medications dangerous for herding breeds?
Many herding breeds (Collies, Australian Shepherds, Shetland Sheepdogs, Border Collies, and others) carry the MDR1 gene mutation (also called ABCB1). This mutation impairs the blood-brain barrier's ability to pump certain drugs out of the brain, leading to drug accumulation and potentially fatal neurotoxicity. Affected drugs include loperamide (Imodium), ivermectin (at higher doses), and several other medications. You can test your dog for the MDR1 mutation through services like Washington State University's Veterinary Clinical Pharmacology Lab.
Can I give my dog melatonin for anxiety?
Yes — melatonin is generally very safe for dogs and commonly recommended for noise phobias (thunderstorms, fireworks), separation anxiety, and seasonal hair loss. The typical dose is 0.1-0.2 mg/kg every 8-12 hours as needed. Give 30-60 minutes before an anticipated stressor. CRITICAL: Check the label carefully — many melatonin products, especially chewable gummies, contain xylitol, which is extremely toxic to dogs. Use only plain melatonin tablets.