Overdose Phenobarbital In Dogs. Overdose can cause depression in the nervous system. As a daytime sedative, a doctor may prescribe anywhere from 30 mg to 120 mg, and as an insomnia treatment, an individual could take as much as 320 mg.

It is possible to overdose on phenobarbital which would result in depression of your dog’s immune system. If your vet prescribes this drug for your pooch, administer it to fido in the dose and frequency she recommends. Mandy had eaten a ninety times overdose!