GABAb receptor agonists (such as Bacofen) lead to decrease in excitatory neurotransmission and increase in inhibitory signals. Common side effects are drowsiness, dizziness, GI problems. Signs of toxicity mainly include neurologic symptoms such as seizures, delirium, and altered mental status at doses greater than 200mg. At much higher doses, cardiac manifestations such as tachycardia, bradycardia, hyper- or hypotension, and respiratory compromise can be seen. Treatment involves supportive care such as IV fluids, respiratory care, hemodynamic support, and anticonvulsants if seizures occur. Activated charcoal can help if baclofen was recently ingested. Hemodialysis can help baclofen clearance to reduce the toxicity duration.
Nicola Y Leung, Ian M Whyte, Geoffrey K Isbister Baclofen overdose: defining the spectrum of toxicity. Emerg Med Australas: 2006, 18(1);77-82