Baclofen

Question 1

Describe the usual features of a large baclofen overdose.

Answer 1

Rapid onset delirium, respiratory depression, coma and seizures

Question 2

With a baclofen overdose, at what dose do patients typically present with significant CNS depression?

Answer 2

> 200 mg in adults

Question 3

How does baclofen work?

Answer 3

Synthetic derivative of GABA. Acts principally on spinal GABA-B receptors inhibiting excitatory neurotransmitter release (glutamate and aspartate)

Question 4

How does baclofen work in overdose?

Answer 4

In addition to inhibiting spinal excitatory amino acid release, at overdose-doses baclofen, inhibits excitatory NTs in the CNS –> coma/sedation/seizures and withdrawal syndromes

Question 5

What are the clinical features of a baclofen overdose?

Answer 5

CNS: delirium, respi depression, coma, seizures. CV: brady/tachy, hyper/hypotension, QT prolongation, heart blocks.

Question 6

What is an important clinical presentation of baclofen that should not be missed?

Answer 6

Large ingestions: coma may be profound. Patient may appear brain dead - fixed/dilated pupils, hypotonia, areflexia (including absent brainstem reflexes)

Question 7

Discuss baclofen withdrawal syndrome.

Answer 7

Occurs between 24-48 hours manifested by seizures, hallucinations, dyskinesia and visual disturbances