 , Alkaloids , Analgesics , Anesthetics , Central Nervous System Agents , Central Nervous System Depressants , Cytochrome P-450 CYP2C8 Substrates , Cytochrome P-450 CYP3A Substrates , Cytochrome P-450 CYP3A4 Substrates , Cytochrome P-450 Substrates , Heterocyclic Compounds, Fused-Ring , High-risk opioids , Hypotensive Agents , Narcotics , Natural Opium Alkaloids , Nervous System , Neuraxial Anesthetics , Opiate Agonists , Opiate Alkaloids , Opioid Agonist , Opioids , P-glycoprotein substrates , Peripheral Nervous System Agents , Phenanthrenes , Sensory System Agents , Serotonergic Drugs Shown to Increase Risk of Serotonin Syndrome , UGT1A1 Substrates , UGT1A3 substrates , UGT2B7 substrates