Drug information of Paroxetine

Paroxetine


Paroxetine is an antidepressant in a group of drugs called selective serotonin reuptake inhibitors (SSRIs). Paroxetine affects chemicals in the brain that may become unbalanced. Paroxetine is used to treat depression, obsessive-compulsive disorder, anxiety disorders, post-traumatic stress disorder (PTSD), and premenstrual dysphoric disorder (PMDD).

Mechanism of effect

paroxetine is a potent and highly selective inhibitor of neuronal serotonin reuptake. Paroxetine likely inhibits the reuptake of serotonin at the neuronal membrane.

Pharmacodynamic

Paroxetine, an antidepressant drug of the selective serotonin reuptake inhibitor (SSRI) type, has no active metabolites and has the highest specificity for serotonin receptors of all the SSRIs.

Pharmacokinetics

Paroxetine hydrochloride is slowly, but completely absorbed following oral administration. Paroxetine distributes throughout the body, including the central nervous system, with only 1% remaining in the plasma. ~ 95% bound to plasma proteins. Paroxetine is extensively metabolized after oral administration, likely in the liver. Approximately 64% of a 30 mg oral solution of paroxetine was excreted in the urine with 2% as the parent compound and 62% as metabolites. Approximately 36% of the dose was excreted in the feces (via bile), mostly as metabolites and less than 1% as parent compound. Half life: 21-24 hours.

Dosage

Usual Adult Dose for Depression Immediate release tablets and suspension: Initial dose: 20 mg orally once a day with or without food, usually in the morning. Maintenance dose: 20 to 50 mg orally once a day with or without food, usually in the morning. Dosage change: Dose may be increased in 10 mg per day increments at intervals of at least one week. Extended release tablets: Initial dose: Paroxetine- naive patients: 25 mg orally once a day with or without food, usually in the morning. Conversion: 30 mg immediate release paroxetine corresponds to 37.5 mg extended release tablets. Maintenance dose: The initial dose may be increased to a maximum of 62.5 mg per day. Dosage change: Dose may be increased in 12.5 mg per day increments at intervals of at least one week. Caution: Extended release tablets should be swallowed whole and not chewed or crushed.

Alerts

1- Patients with major depressive disorder (MDD), both adult and pediatric, may experience worsening of their depression and/or the emergence of suicidal ideation and behavior (suicidality) or unusual changes in behavior 2- Paroxetine tablets are not approved for use in treating bipolar depression. 3- The development of a potentially life-threatening serotonin syndrome has been reported with SNRIs and SSRIs, including Paroxetine. 4- Paroxetine tablets should be used cautiously in patients with a history of mania.

Points of recommendation

1- It should be discontinued in any patient who develops seizures. 2- Hyponatremia may occur as a result of treatment with SSRIs and SNRIs, including Paroxetine. In many cases, this hyponatremia appears to be the result of the syndrome of inappropriate antidiuretic hormone secretion (SIADH) 3- Patients should be cautioned about the risk of bleeding associated with the concomitant use of Paroxetine and NSAIDs, aspirin, or other drugs that affect coagulation.

Pregnancy level

D


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