Induction Agents

Depress the reticular activating system (a polysynaptic network of neurons & regulatory centers) located in the brainstem that controls vital functions, including consciousness. In clinical doses – they affect the function of nerve synapses rather than axons

They suppress the transmission of excitatory neurotransmitters (ACh) & enhance transmission of inhibitory neurotransmitters (GABA) by interfering with transmitter release (presynaptic) and selectively interacting with receptors (postsynaptic)

Structure: O₂ on #2 Carbon atom

Examples: phenobarbital, pentobarbital, secobarbital, methohexital

Structure: sulfur on #2 Carbon atom

Examples: thiopental, thiamylal

• onset = 30 seconds (high lipid solubility)
• dose = 3 - 6mg/kg for induction
• rapid awakening d/t redistribution
• highly protein bound (up to 86%)
• great affinity for fat (can lead to accumulation with large/repeated doses) --> doses should be calculated on IBW