Fluoxetine measurement is used to monitor the levels of the drug in the body during treatment, to evaluate potential toxicity, and to assess patient compliance.
Fluoxetine is an antidepressant medication that belongs to a class of drugs called selective serotonin reuptake inhibitors (SSRIs). Fluoxetine (Ladose®, Prozac®) is approved for major depressive disorder, obsessive-compulsive disorder, panic disorder, bulimia, binge eating disorder, premenstrual dysphoric disorder, and bipolar depression as well as treatment-resistant depression when used in combination with olanzapine. Non-approved uses for fluoxetine include social anxiety disorder (social phobia), post-traumatic stress disorder in adults, borderline personality disorder, Raynaud phenomenon, and selective mutism.
Serotonin and norepinephrine, both biological amines, have been shown to play a role in depression. Low concentrations of serotonin appear in the cerebrospinal fluid of patients with depression. Fluoxetine exerts its effects by blocking the reuptake of serotonin into presynaptic serotonin neurons by blocking the reuptake transporter protein.
Fluoxetine's active metabolite is norfluoxetine, which gets produced when the cytochrome P450 enzyme (CYP2D6) acts on it. Fluoxetine has several drug-drug interactions due to its metabolism at the CYP2D6 isoenzyme. Fluoxetine has a half-life of 2 to 4 days, and its active metabolite norfluoxetine has a half-life of 7 to 9 days.
