For example: Most flea medications range from 5-20 pounds, 21-55 pounds, and 56+ pounds. Why would a pet who is 22 pounds require a dose that is also suitable for a 55 pound pet? Isn’t there a concern of over medicating since there’s only a 2 pound difference?
In: Chemistry
Weight is one factor, but even if it was the only factor the manufacturers know they can not rely on consumers to do math. The doses are determined to be safe for the weight range and they probably end up under-dosing the animals at the high end of the range.
This is reflecting something known as an ld50, where its measured in a weight per weight ratio where its toxic. Say a drug has an ld50 of 10 mg/kg, a 100 kg man would need to have 1000 mg or 1g of that drug for it to likely kill them (if we had 10 100 kg participants, 5 would likely die (hence ld50)). Likewise for doggos.
It depends on the therapeutic index. Many drugs have a wide range of levels that will give the desire effect before you reach toxic levels. Other drugs aren’t so forgiving.
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