Answer
Phenobarbital has a plasma half-life of up to about 100 hours in adults and 75 hours in children, increased in the elderly, in overdosage and in renal or hepatic disease.
Sources for this answer
- Phenobarbital Elixir BPThornton & Ross Ltd · emc · SmPC §5.2 Pharmacokinetic properties · Version 11Document updated
Sources checked