baclofen overdose

introduction

baclofen is a synthetic derivative of GABA and in Rx doses, mainly acts upon GABA-B receptors, inhibiting the release of the excitatory amino acids glutamate and aspartate
in overdoses > 200mg in adults, this can result in significant CNS depression causing sedation and coma which may be profound and prolonged with hyporeflexia, hypotonia, fixed, dilated pupils, lasting 24-48hrs and thus admission to a ICU/HDU is generally needed
it may also cause:
- resp. depression
- sinus bradycardia
- sinus tachycardia
- hypertension
- 1st degree heart block
- prolonged QTc (rare)

most overdoses are minor and if asymptomatic or ingestion < 200mg in adults, can usually be discharged within 4hrs following ingestion
in severe overdoses, Mx is supportive care

following recovery from overdose one should recommence usual baclofen doses to prevent withdrawal syndrome (see below)