Dosage

The dosage for dog medications refers to the exact amount of active ingredient per kilogram of body weight required for a therapeutic effect. Unlike in humans, it is calculated exclusively based on weight; a 5 kg Chihuahua needs approximately one-twentieth of the dosage of a 40 kg shepherd dog.

How does the vet calculate the correct dosage?

Vets calculate the dosage based on body weight and active ingredient. For Metacam (meloxicam), for example, the practice determines the amount individually, adjusted for weight, pre-existing conditions and concomitant medication; there is deliberately no universally applicable formula for self-calculation here.

Most dog medications have therapeutic windows between efficacy and toxicity; too little has no effect, too much causes harm. For antibiotics such as amoxicillin, the vet practice determines the dosage and dosing schedule, adjusted for the pathogen and indication.

Why do dog breeds react differently to dosages?

Sighthounds metabolise anaesthetic agents such as propofol significantly more slowly than other breeds; their dosage is reduced by 30–50%. Collies and related breeds often have an MDR1 gene defect: they tolerate ivermectin (against parasites) only in microdoses, whereas a beagle can easily handle the standard dose.

Brachycephalic breeds (Pug, Bulldog) require lower dosages of sedatives, as their breathing problems increase the risk associated with anaesthesia.

What happens with incorrect dosing?

Overdoses often become apparent within hours. With painkillers (NSAIDs) such as Rimadyl, stomach ulcers develop; with heart medications such as digitoxin, arrhythmias occur. Underdosing antibiotics promotes resistance; the pathogen survives and becomes insensitive.

A special feature: paracetamol is highly toxic to dogs; even 15 mg/kg can be fatal. Humans take 500–1000 mg per dose; for a dog, half a tablet would be life-threatening.

What should I do in an emergency?

In case of suspected poisoning or an allergic reaction, one thing counts above all: contact the vet practice or an emergency number immediately. Whether and how much activated charcoal or a medication such as cetirizine is appropriate is decided by the professional on the phone; there is deliberately no dosage to memorise here.