Mechanism of Action: Fluoxetine is a selective serotonin reuptake inhibitor (SSRI). It works by increasing the levels of serotonin, a neurotransmitter in the brain, by inhibiting its reuptake into the presynaptic cell. This helps in maintaining higher levels of serotonin in the synaptic cleft, leading to improved mood and emotional well-being.

Absorption and Metabolism: Fluoxetine is well absorbed orally and has a long half-life. It is metabolized in the liver by the cytochrome P450 system, primarily by the CYP2D6 isoenzyme.

Prescribe TCAs with caution to people with:

• A history of bipolar disorder or psychosis.

• Increased risk of suicide.

• Cardiovascular disease.

• Older age (increased susceptibility to adverse effects).

• Chronic constipation.

• Epilepsy.

• Diabetes mellitus.

• Mild to moderate hepatic impairment.

• Hyperthyroidism (risk of arrhythmias).

• Susceptibility to angle-closure glaucoma.

• Phaeochromocytoma (risk of arrhythmias).

• Prostatic hypertrophy.

• Urinary retention.