Flashcards in Pharm - Gen Anesthetics - Kisby Deck (10):
What are the 2 general classes of GA?
1. Inhalation - can be halogenated or non-halogenated
What are some pharmacokinetic factors of inhalation GAs that affect depth of anesthesia?
1. Partial pressure = conc in blood or other tissues
2. Minimal alveolar concentration (inversely related to oil/gas coefficient)
3. Blood/gas partition coefficient (lower coefficient = faster induction & recovery and vice versa)
4. Oil/gas partition coefficient = lipid solubility (higher coefficient, more potent GA)
What determines uptake and distribution of inhalation GAs?
• Uptake of GA into tissues is based on their perfusion & solubility
• Highly perfused tissues are the first to encounter inhaled GAs
• Solubility & small volume limit GA capacity
What is the MOA of GAs?
• Enhance inhibitory postsynaptic channel activity (GABA & Glycine)
• Inhibit excitatory synaptic channel activity (nicotinic receptors & Glutamate)
• Non-halogenated inhalation GA
• Weak anesthetic & good analgesic
• MOA: NMDA antagonist
• Caution: can cause diffusional hypoxia
• Abuse can lead to neuropathies & magaloblastic anemia
Volatile Halogenated Agents
• Drugs: Isoflurane, Desflurane, Sevoflurane
• Reduce BP by assign N2O
• Depress ventilation
• SE: life-threatening malignant hyperthermia
What are some general characteristics of IV GAs?
• Used to induce anesthesia & reduce the amount of inhalation anesthetics
• Rapid onset, short half-life, recovery due to redistribution
• Advantage: less CV depression
• IV GA
• Dissociative anesthetic = catatonia, analgesia, w/o LOC
• Use: diagnostic & minor surgeries
• MOA: reduces excitation by blocking glutamate receptors (NMDA)
• SE: increases catecholamine release
• IV GA
• Most commonly used IV GA for induction & maintenance
• MOA: enhances inhibition by binding to GABA receptor