Med Considerations for Cats and Dogs

What are potential concerns with using human meds in dogs or cats?

Using human meds for pets is “extra-label” or off-label use and requires a prescription or vet’s recommendation.

Species, breed, and pet size can impact meds.⁸

Animals metabolize drugs differently than humans. For example:⁸

Drugs that are safe to use in humans can potentially lead to toxicity in pets.⁸

Human meds that may be safe for use in pets may be dosed differently than in humans.⁸

What are some dosing examples of OTC meds used for pets?

Medication

Example Oral Dosing in Dogs¹⁰

Example Oral Dosing in Cats¹⁰

Antihistamines

Cetirizine

1 mg/kg (or 10 to 20 mg) every 12 to 24 hours⁵

1 mg/kg (or 5 mg) every 12 to 24 hours⁵

Chlorpheniramine

<20 kg: 4 mg every 8 hours;⁵
>20 kg: 0.25 to 0.5 mg/kg (or 8 mg) every 8 hours⁵

1 to 2 mg every 8 to 12 hours

Diphenhydramine

2 mg/kg three times daily

2 mg/kg two to three times daily

Dimenhydrinate

2 to 4 mg/pound every 8 hours

12.5 mg every 8 hours

Fexofenadine

2 to 5 mg/kg every 12 to 24 hours⁵

10 to 15 mg every 12 to 24 hours⁵

Loratadine

0.125 to 0.25 mg/kg once to twice daily

N/A

Gastrointestinal Medications

Famotidine

0.5 mg/kg once daily

Ranitidine (Canada)

1 mg/kg twice daily

Loperamide

0.08 to 0.2 mg/kg every 8 to 12 hours (see breed-specific caution, below)

N/A

Omeprazole

0.5 to 1 mg/kg once daily

0.7 mg/kg once daily

Simethicone

25 to 200 mg daily

0.3 to 0.5 mL of the infant drops two or three times daily

Cough Medications

Dextromethorphan

0.5 to 2 mg/kg every 6 to 8 hours

Guaifenesin

3 to 5 mg/kg every 8 hours

What are some cautions to consider before using OTC and human prescription meds for pets?

Acetaminophen is contraindicated in cats because they can’t metabolize it.⁴ Acetaminophen can be used judiciously in dogs (e.g., careful dosing, consideration of periodic lab monitoring with chronic use).⁴

Nonsteroidal anti-inflammatory drugs (NSAIDs) may not be safe. For example:

Loperamide should not be used for some herding dog breeds (e.g., Collies, Australian Shepherds, Old English Sheepdogs, German Shepherds) without genetic testing.^5,17 These breeds may experience toxicity (excess salivation, ataxia, inability to stand or walk) if they have the ABCB-1 gene deletion and thus do not make functional p-glycoprotein.⁵

Phenazopyridine (US only) is contraindicated in cats, due to risk of methemoglobinemia and irreversible oxidative changes in hemoglobin, leading to anemia.²

Topical anesthetics (e.g., lidocaine, benzocaine) are hazardous if ingested or inappropriately applied to pets.

Oral steroids: Prednisone or prednisolone can be used in dogs. Prednisolone is preferred in cats. Cats are not able to convert prednisone to prednisolone (active form) well and prednisolone has better absorption than prednisone.¹⁸

What are some problematic inactive medication ingredients to be aware of with pets?

Animals are very susceptible to the effects of alcohol. Alcohol can lead to serious effects, including dangerous drops in blood glucose, blood pressure, and body temperature if consumed by pets.⁹ Look for alcohol as an inactive ingredient in liquid medications before suggesting them for a pet or filling a pet prescription.¹⁰

What are some examples of alternative products or supplements that can be harmful to pets?

Avoid giving human glucosamine products to cats or dogs. The dose may be too high, the glucosamine may be in a form that is harder to digest, and the product may contain unsafe inactive ingredients (e.g., xylitol).^14,15

Ma Huang and Guarana: alone or combined can lead to severe hyperactivity, tremors, seizures, vomiting, and tachycardia.⁵ Fatalities have been reported in dogs.²¹

Kratom: may cause agitation and tachycardia, or opioid-like effects at larger doses (vomiting, sedation, stupor).⁵

Pennyroyal (a natural flea treatment): can be lethal, especially for small animals.^5,19

Tea tree oil (especially toxic to cats due to their deficient glucuronic acid conjugation): can cause severe neurologic problems and liver damage if consumed or topically absorbed.²⁰

What are some examples of human prescription meds that are dosed differently in dogs and cats?

Keep in mind, pets may need very different med doses than used for humans. See examples below:

What are some safeguards when dispensing controlled substances for pets?

Stay alert for red flags that an owner may be misusing or diverting controlled substance Rxs prescribed for their pets. Examples of red flags might include:

You may be required to report controlled substance prescriptions dispensed to pets to Rx drug monitoring programs in your state or province.

How are pet prescriptions different than human prescriptions?

The pet is the patient, the pet owner is the client.⁸

Brand names for pet meds may differ from same-ingredient human meds. Examples include Thyro-Tabs (levothyroxine), Clavamox (amoxicillin/clavulanate), and Metacam (meloxicam).

Veterinary abbreviations may differ. For example, you may see “SID” as a dosing abbreviation on pet prescriptions. SID means once daily.⁸

Liquid Rx strengths are rarely written as “x mg/5 mL.” So instead of amoxicillin 250 mg/5 mL, expect to see amoxicillin 50 mg/mL.⁸

What are some tips to prevent errors between pet and human Rxs?

Follow your pharmacy’s policy when setting up pet profiles, such as adding:

Verify you have selected the correct patient profiles before entering Rxs. Pet’s and their owner’s profile will have the same last name, address, and phone number.

Generally, avoid dispensing pet Rxs under the owner’s name. This can lead to confusion or possible fraud if the Rx is accidentally billed to the owner’s insurance.

Confirm med histories. There have been cases where outpatient pet meds autopopulated the electronic med list of the pet owner when admitted to the hospital.

Which resources are available to help answer questions about meds and pets?

Plumb’s Veterinary Drugs. (print edition or digital [subscription required]) (Includes drug monographs discussing pharmacology, uses and indications, pharmacokinetics, contraindications and precautions, adverse effects, acute toxicity, drug interactions, dosing information, laboratory concerns, and monitoring parameters.).

The Merck Veterinary Manual (https://www.merckvetmanual.com/) (disease state management including pharmacotherapy (including some dosing information), toxicology, and information for pet owners on routine care and diseases).

The American Society for the Prevention of Cruelty to Animals (ASPCA) Animal Poison Control Center. http://www.aspca.org/pet-care/poison-control/. (Provides links to veterinary medicine toxicology resources).

Animal Poison Control Center 888-426-4435 (U.S. and Canada). Note that the Animal Poison Control Center hotline may charge a consultation fee. Pharmacists may want to consider keeping a list of local emergency animal clinics that are open after hours for referral to pet owners.