Dog Medication Dosage Calculator
⚠️ 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.
Breeding a dam? Pregnancy and nursing change the answer for most of these medications. Every result below includes a dedicated pregnant & nursing section with its sources — read it before dosing a bred or lactating bitch.
Your dog's weight
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Medications that are NEVER safe for dogs
There is no safe dose of anything in this list. The figures below are the amounts at which veterinary poison-control references expect a dog to be poisoned — they exist so you can tell an emergency from a scare if your dog has already swallowed something. They are not limits to stay under. If your dog ate any amount, call one of the numbers at the bottom of this page now rather than waiting for signs.
Enter a weight in step 1 to see what these amounts work out to for your dog.
Ibuprofen (Advil, Motrin)
Causes stomach ulcers and kidney failure. Dogs have far less tolerance for it than people do.
Naproxen (Aleve)
Roughly twenty times more dangerous to dogs than ibuprofen, and it stays in their system far longer.
Acetaminophen (Tylenol, paracetamol)
Destroys liver cells and damages red blood cells so they can no longer carry oxygen. Fatal to cats at any dose.
Pseudoephedrine (Sudafed, and the “-D” version of most allergy tablets)
A stimulant. It drives heart rate and blood pressure up hard, and the margin in dogs is genuinely narrow.
Xylitol (birch sugar — in gum, sleep aids, and chewable supplements)
Triggers a life-threatening blood sugar crash within 30–60 minutes and can cause liver failure over the following days. Check the label of every chewable and liquid before it goes near a dog.
Disclaimer: This calculator provides standard veterinary reference ranges for informational purposes only. It is not a substitute for veterinary advice, diagnosis, or treatment, and no veterinarian-client-patient relationship is created by using it. Dosing can vary based on your dog's breed, age, health conditions, and other medications. Always consult your veterinarian before administering any medication.
Pregnant and nursing dams: the pregnancy and lactation guidance shown with each medication reflects what the cited label or veterinary reference actually states. For several of these drugs the honest answer is that safety in breeding, pregnant, or lactating dogs has never been formally studied — that is not the same as being proven safe. Never dose a bred or nursing bitch without veterinary direction.
Sources: dam-safety guidance is drawn from FDA product labels (via DailyMed), VCA Animal Hospitals drug monographs, AKC veterinary guidance, and peer-reviewed studies, each linked with its medication above. Dose ranges follow standard veterinary references including Plumb's Veterinary Drug Handbook and the Merck Veterinary Manual.
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.
“How much Sudafed can I give my dog?” — the answer is none
People search for a dose of pseudoephedrine, ibuprofen, and Tylenol for dogs every day. None of those drugs has a safe canine dose, so the calculator answers a different and more useful question instead: at what amount does a swallowed dose become an emergency? Enter your dog's weight and the never-safe list will translate the published poisoning thresholds into real milligrams and, where it applies, into a number of ordinary tablets.
The numbers are sobering once they are in tablets rather than milligrams per kilogram. Pseudoephedrine causes agitation, a racing heart, tremors, and dangerously high blood pressure at 5–6 mg/kg, and deaths have been reported at 10–12 mg/kg. For a 10 lb dog that lower figure is roughly a single 30 mg Sudafed tablet. Naproxen is the other one people underestimate: it is far more dangerous to dogs than ibuprofen, with stomach ulceration reported from as little as 5 mg/kg — well under one Aleve tablet for a small dog.
Treat every one of those figures as a description of a poisoning, never as a ceiling to stay beneath. If your dog has swallowed any amount of a human medication, the right move is to call the ASPCA Animal Poison Control Center at 888-426-4435 or the Pet Poison Helpline at 855-764-7661 straight away. Both charge a consultation fee and both are staffed around the clock. Do not wait for symptoms, and do not induce vomiting unless one of them tells you to.
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.
Pregnant and nursing dams need a different answer
Pregnancy and lactation change the safety picture for almost every medication on this page. Of the eleven listed here, ten carry a pregnancy or nursing restriction in their label or veterinary monograph — only 3% hydrogen peroxide does not, and that is because its published do-not-use list simply never addresses pregnancy, not because it has been cleared for use in dams.
Read the distinction carefully, because these are not the same thing. Buffered aspirin and Imodium carry explicit do-not-use guidance for bred or nursing bitches. Cerenia is different: its FDA label states that safety in breeding, pregnant, or lactating dogs has never been evaluated — unstudied, not proven harmful. Benadryl, Pepcid AC, omeprazole, melatonin, and cetirizine sit in a use-with-caution tier, and dimenhydrinate carries the most favorable note of the group — VCA calls it likely safe, which is still not the same as proven. Calcium runs in the opposite direction to what many breeders expect: contraindicated during pregnancy, legitimate under veterinary direction during lactation. The calculator shows each medication's status with the label or monograph it comes from, linked so you can read the original wording yourself.
What is deliberately not on this calculator, and why
Two of these are left off on safety grounds. The other three are left off because a weight-based dose box is simply the wrong shape for them.
Pepto-Bismol (bismuth subsalicylate) is excluded because of what it would sit next to. Bismuth subsalicylate is aspirin-like, and this calculator already carries a buffered aspirin entry — publishing both invites a breeder to give the two together and stack salicylates in a species that clears them slowly, which is why the canine aspirin interval is every 48 hours rather than daily. The AKC's chief veterinary officer rarely recommends it in any case, because the salicylate can cause gastric bleeding that the product's own black stool then hides. Pregnant and nursing dams, and dogs on NSAIDs such as carprofen or deracoxib, should not receive it at all.
Meclizine (Bonine) is excluded because there is a better answer for the same problem. It has been reported to cause birth defects in laboratory animals and to reduce milk supply — the two things a breeder can least afford. For a dam or a litter that travels, dimenhydrinate is in the calculator above and carries the most favorable pregnancy note of anything here.
Activated charcoal is the natural sequel to the hydrogen peroxide entry above, and it is genuinely part of poisoning treatment at around 1 g per kg. It is left out because it is something a veterinarian administers after deciding whether the dog should have been made to vomit at all — and for a number of poisons, inducing vomiting is actively contraindicated. The right sequence at home is call poison control, then transport.
Folic acid is dosed as a flat 5 mg per day, not by weight, and the evidence is genuinely split. In a Boston Terrier colony, supplementation tracked with cleft palate falling from about 17.6% to 4.2%. But a controlled trial in a low-risk colony of Labradors and Golden Retrievers found no reduction in cleft palate, umbilical hernia, stillbirth, or C-section rate. The reasonable reading is that it may matter in high-risk brachycephalic and toy lines and has not been shown to matter in low-risk breeds.
Fish oil (EPA and DHA) is a dietary component rather than a drug — AAFCO sets a minimum for growth and reproduction, which makes it one of the few things on this list affirmatively recommended during pregnancy and lactation rather than merely tolerated. A two-generation Beagle study found algal oil well tolerated across gestation, lactation, and growth at many times that minimum. Because it is fed as part of the diet, it belongs in a nutrition conversation with your vet, not in a per-dose calculator.
| Medication | Standard dose | Pregnant / nursing | Key warning |
|---|---|---|---|
| Benadryl | 2–4 mg/kg | Use with caution | Use ONLY plain diphenhydramine — no Benadryl-D, no combination products |
| Pepcid AC | 0.5–1 mg/kg | Use with caution | Use ONLY plain famotidine — not Pepcid Complete (contains calcium carbonate + magnesium) |
| Prilosec OTC | 0.5–1 mg/kg | Use with caution | Not a give-it-and-see drug — omeprazole treats ulcers and erosions, not everyday gas or a single skipped meal |
| Cerenia | 2–8 mg/kg | No safety data | PRESCRIPTION ONLY — requires veterinary authorization |
| Imodium | 0.08–0.1 mg/kg | Not recommended | DANGEROUS for herding breeds (Collies, Shelties, Aussies, Border Collies) — MDR1 gene mutation |
| Aspirin (buffered) | 5–10 mg/kg | Not recommended | Short-term use ONLY — GI ulcers develop quickly in dogs |
| Zyrtec | 1 mg/kg | Use with caution | NEVER use Zyrtec-D or any pseudoephedrine combination — pseudoephedrine is dangerous to dogs |
| Dramamine | 8 mg/kg | Use with caution | Do NOT give to newborn or very young puppies |
| Calcium (elemental) | 25–50 mg/kg/day | Nursing only — never in pregnancy | NEVER supplement calcium during pregnancy — Merck states it is not indicated and may CAUSE rather than prevent eclampsia |
| Melatonin | 0.1–0.2 mg/kg | Use with caution | Check label — MUST NOT contain xylitol (common in chewable forms) |
| Hydrogen Peroxide 3% | 1–2 mL/kg | No specific restriction | ONLY use when directed by a veterinarian or poison control |
Medication dosage FAQs
1How much Benadryl can I give my dog?
The standard veterinary dose for Benadryl (diphenhydramine) in dogs is 2-4 mg per kg of body weight (rule of thumb: 1 mg per pound), given every 8-12 hours. For a 50-lb dog, that's typically 50 mg per dose (two 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.
2Can 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.
3What 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.
4How 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.
5Why 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.
6Can 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.
7Does my dog's exact weight matter for dosing?
Yes — accurate weight is essential for safe dosing. A 10% error in weight can lead to meaningful under- or overdosing, especially for medications with narrow safety margins like aspirin or hydrogen peroxide. Weigh your dog on a pet scale or use the 'step on, step off' method with a bathroom scale. For small dogs and puppies, use a kitchen scale for accuracy within 0.1 lb. Never estimate weight for medication purposes.
8Which of these medications are safe for a pregnant or nursing dam?
Almost every medication in this calculator carries a pregnancy or nursing restriction, so assume nothing is cleared for a bred or lactating bitch without asking your vet. Buffered aspirin and Imodium (loperamide) have explicit do-not-use guidance — the FDA label for buffered aspirin states that safe use in pregnant or breeding animals has not been proven, and the AKC lists pregnant or nursing bitches among dogs that should not receive Imodium. Cerenia's FDA label states that safety in breeding, pregnant, or lactating dogs has not been evaluated, which means unstudied rather than proven harmful. Benadryl, Pepcid AC (famotidine), omeprazole (Prilosec), melatonin, and cetirizine (Zyrtec) fall into a use-with-caution tier. Dimenhydrinate (Dramamine) has the most favorable note of the group — VCA describes it as likely safe in pregnant or nursing pets, though that is still short of proven. Calcium is a special case: it is contraindicated during gestation but has a legitimate vet-directed role during lactation. Only 3% hydrogen peroxide has no pregnancy-specific restriction in its published monograph, and that is an absence of guidance rather than a clearance — the usual aspiration risks still apply. Each medication in the calculator shows its status alongside the label or veterinary monograph it came from.
9Can I give a nursing dam calcium to prevent eclampsia?
Not during pregnancy — and this is one of the most common and most consequential mistakes in breeding. The Merck Veterinary Manual states that oral calcium supplementation during gestation is not indicated and may cause rather than prevent postpartum hypocalcemia (eclampsia). Supplementing a pregnant dam suppresses the hormonal machinery she needs to mobilize her own calcium once lactation begins, which can make eclampsia more likely, not less. Calcium does have a legitimate role after whelping, under veterinary direction, and eclampsia itself is a true emergency requiring immediate veterinary treatment — a dam showing restlessness, panting, stiffness, tremors, or a wobbly gait in the weeks after whelping needs a vet now, not a supplement.
10Pepcid or Prilosec for a dog — which one, and how much?
They are different classes and they are not interchangeable. Pepcid AC (famotidine) is an H2 blocker, dosed at 0.5-1 mg/kg every 12-24 hours, and it is the reasonable choice for a short bout of stomach upset. Prilosec (omeprazole) is a proton pump inhibitor at 0.5-1 mg/kg, and the Merck Veterinary Manual describes H2 blockers like famotidine as inferior to proton pump inhibitors for treating actual gastric ulcers. Two practical differences matter. First, omeprazole should be given 30-45 minutes before a meal and, per the 2018 ACVIM consensus statement on gastrointestinal protectants, twice daily rather than once — once-daily dosing does not suppress acid adequately over 24 hours. Second, omeprazole is much harder to stop: abrupt discontinuation after weeks of use causes rebound acid oversecretion, so vets taper it. That combination makes omeprazole a vet decision rather than a self-serve swap when Pepcid is not working.
11Should I give my pregnant dog fish oil or folic acid?
These are the two supplements with real reproduction-specific evidence, and neither is dosed by body weight, which is why they are not in the calculator. Fish oil is the stronger case: AAFCO sets an EPA and DHA minimum specifically for growth and reproduction, making it one of the few things affirmatively recommended during pregnancy and lactation rather than merely tolerated, and a two-generation Beagle study found algal oil well tolerated through gestation, lactation, and puppy growth at many times that minimum. Folic acid is dosed as a flat 5 mg per day and the evidence is split by breed risk — a Boston Terrier colony saw cleft palate rates fall from roughly 17.6% to 4.2%, but a controlled trial in a low-risk Labrador and Golden Retriever colony found no reduction in cleft palate, umbilical hernia, stillbirth, or C-sections. Discuss both with your vet as part of the dam's diet rather than treating them as medications. Calcium is the important exception to the supplement-during-pregnancy instinct: it is contraindicated during gestation and can make eclampsia more likely, not less.
12How much pseudoephedrine (Sudafed) can I give my dog?
None. There is no safe dose of pseudoephedrine for dogs at any weight — it is a stimulant with a genuinely narrow margin in this species. The Merck Veterinary Manual reports that clinical signs appear at 5-6 mg/kg and that deaths have occurred at 10-12 mg/kg. Put in practical terms, a single 30 mg Sudafed tablet is around the poisoning threshold for a 10 lb dog. Signs include agitation, hyperactivity, dilated pupils, a racing heart, high blood pressure, tremors, head bobbing, hiding, and vomiting; they can begin within 30 minutes, or be delayed 2-8 hours with extended-release products, and can last 24-48 hours once they start. This also applies to any allergy product with a 'D' after its name, such as Zyrtec-D or Claritin-D, because that D is pseudoephedrine. If your dog has swallowed any amount, call the ASPCA Animal Poison Control Center at 888-426-4435 or the Pet Poison Helpline at 855-764-7661 immediately rather than waiting for signs.
13How much Tylenol or ibuprofen can I give my dog?
Neither one, at any weight. Acetaminophen (Tylenol, paracetamol) damages the liver and converts hemoglobin into a form that cannot carry oxygen; the Merck Veterinary Manual places liver injury at doses above 100 mg/kg and methemoglobinemia above 200 mg/kg in dogs. For a 20 lb dog, 100 mg/kg is under three extra-strength tablets. Ibuprofen (Advil, Motrin) causes vomiting, diarrhea, and stomach ulceration at 100-125 mg/kg, kidney failure at 175-300 mg/kg, seizures and coma above 400 mg/kg, and is potentially lethal above 600 mg/kg. Naproxen (Aleve) is the most dangerous of the group despite being the least suspected — ulceration has been reported at just 5 mg/kg. If your dog needs pain relief, veterinary NSAIDs such as carprofen or meloxicam are designed for dogs and are vastly safer; buffered aspirin is the only over-the-counter option occasionally considered acceptable, short-term and with veterinary sign-off. If a dose has already been swallowed, treat it as an emergency and call poison control.
14Can I give my dog Pepto-Bismol, and how much?
This calculator deliberately does not give a Pepto-Bismol dose, and the reason is worth understanding. Bismuth subsalicylate is aspirin-like, and dogs clear salicylates slowly — that is why the standard canine aspirin interval is every 48 hours rather than daily. Because this tool already includes buffered aspirin, publishing a Pepto-Bismol dose alongside it would make it easy to give both and stack salicylates without realizing it. The AKC's chief veterinary officer rarely recommends it regardless, noting that salicylate-related gastric bleeding can be masked by the black stool the product itself causes. It should not be given at all to pregnant or nursing dams, or to dogs already taking an NSAID such as carprofen (Rimadyl) or deracoxib (Deramaxx). For a dog with diarrhea, the safer path is a vet call rather than a home dose.
15Is meclizine or Dramamine better for a dog with motion sickness?
Dramamine (dimenhydrinate) is the better choice for a breeding dog, which is why it is in this calculator and meclizine is not. Meclizine has been reported to cause birth defects in laboratory animals and to reduce milk supply — both serious problems for a bred or nursing bitch. Dimenhydrinate is dosed at 8 mg/kg up to three times daily, given 30 to 60 minutes before travel, and VCA's monograph describes it as likely safe in pregnant or nursing pets, the most reassuring pregnancy language attached to any medication in this tool. Likely safe still is not proven safe, so clear it with your vet before hauling a bred bitch or a litter. Note that dimenhydrinate should not be given to neonatal puppies.
16Can I use expired medications for my dog?
Most medications gradually lose potency after their expiration date but don't become dangerous. However, the rate of degradation varies — some medications (like liquid antibiotics) break down quickly, while tablets are more stable. In an emergency, a recently expired Benadryl tablet is unlikely to cause harm but may be less effective. For non-emergencies, always use in-date medications. Never use expired hydrogen peroxide to induce vomiting — it loses effectiveness rapidly and may not work when you need it most.