noramitriptyline
Noramitriptyline is the primary active metabolite of amitriptyline, a tricyclic antidepressant. It is formed in the body through the demethylation of amitriptyline by cytochrome P450 enzymes, mainly CYP2C19 and CYP1A2. Noramitriptyline itself possesses pharmacological activity, contributing to the overall antidepressant and anxiolytic effects of amitriptyline. It acts by inhibiting the reuptake of norepinephrine and serotonin in the brain, increasing their availability in the synaptic cleft. While amitriptyline is the prescribed medication, noramitriptyline is the substance primarily responsible for many of its therapeutic and side effects. The concentration of noramitriptyline in the bloodstream can be influenced by genetic variations in the metabolic enzymes, leading to differences in drug response and potential for adverse reactions among individuals. Monitoring noramitriptyline levels can sometimes be used in clinical practice to optimize amitriptyline dosage.