The therapeutic range for phenobarbitone in the treatment of idiopathic epilepsy in dogs is a serum concentration of 20-40mg/ml

In the management of idiopathic epilepsy in dogs the reported therapeutic range for phenobarbitone is a serum concentration of 20-40mg/ml and initially it is suggested that clinicians establish a serum concentration of 20-25mg/ml. If seizures are occurring at the same frequency, or more frequently, after 30 consecutive days of treatment whilst maintaining  this serum concentration the aim should be to increase serum concentrations by 5mg/ml increments until the seizure frequency rate falls. The following simple formula can be applied to determine the new dose rate to give :

T = D/A  x C

Where :

T = The new total #mg phenobarbitone PO needed per day

D =  The desired new serum concentration (eg A plus 5)

A = The current actual serum concentration

C = The current # mg phenobarbitone being given PO per day 

  Last updated : January 2016