A 60-year-old man on ICU is being treated with IV phenytoin for status epilepticus. The pharmacist notes he has a serum albumin of 18 g/L (normal 35-5...

Question

A 60-year-old man on ICU is being treated with IV phenytoin for status epilepticus. The pharmacist notes he has a serum albumin of 18 g/L (normal 35-50). His total phenytoin level is reported as 8 mg/L (therapeutic range 10-20 mg/L for total phenytoin). Should the phenytoin dose be increased?

Accepted Answer

Request a free phenytoin level and adjust dose accordingly

Answer

Yes - the level is subtherapeutic and the dose should be increased

Answer

No - the free (unbound) phenytoin concentration is likely therapeutic because hypoalbuminaemia increases the free fraction

Answer

Yes - but switch to oral phenytoin to avoid IV toxicity

Answer

No - phenytoin levels are unreliable in ICU patients and should not be measured

uk-fficm MCQ (SBA): Therapeutic Drug Monitoring

A 60-year-old man on ICU is being treated with IV phenytoin for status epilepticus. The pharmacist notes he has a serum albumin of 18 g/L (normal 35-50). His total phenytoin level is reported as 8 mg/L (therapeutic range 10-20 mg/L for total phenytoin). Should the phenytoin dose be increased?