Paroxetine
Mechanism :
Paroxetine is a selective serotonin reuptake inhibitor (SSRI) for oral administration. The antidepressant, antiobsessive-compulsive, and antibulimic actions of fluoxetine are presumed to be linked to its inhibition of CNS neuronal uptake of serotonin.
Indication :
- Obsessive compulsive disorder
- Panic disorder
- Anxiety disorder
- Social phobia
- Idiopathic musculoskeletal pain
Contraindications :
Concomitant use in patients taking monoamine oxidase inhibitors (MAOIs) and pimozide is contraindicated. Also contraindicated in patients with a hypersensitivity to fluoxetine, hepatic or renal insufficiency.
Dosing :
Paroxetine is not FDA-approved for use in children and adolescents less than 18 years of age.
Obsessive compulsive disorder (OCD):
Oral: 12-18 years: 20 mg once daily in the morning. Increase weekly by 10 mg/day to max dose of 60 mg.
Panic disorder:
Oral: 12-18 years: 10 mg once daily in the morning. Increase weekly by 10 mg/day to max dose of 40 mg.
Idiopathic musculoskeletal pain:
Oral: 8-12 years: 10 mg and 12-18 years: 20 mg once a day.
Adverse Effect :
Commonly seen side effects are nausea and gastrointestinal symptoms generally. Headache, light headedness, restlessness, anxiety, weight loss, seizures, rash, urticaria, fever, neuroleptic malignant syndrome, social disinhibition, euphoria, precipitation of mania, diminished libido and anorgasmia may be seen.
Interaction :
Lithium: There have been reports of both increased and decreased lithium levels when lithium was used concomitantly with paroxetine.
Tryptophan: Adverse reactions, including agitation, restlessness, and gastrointestinal distress.
Benzodiazepines: Half-life of concurrently administered diazepam may be prolonged in some patients. Coadministration of alprazolam and paroxetine has resulted in increased alprazolam plasma concentrations.
Haloperidol and Clozapine: Elevation of blood levels of haloperidol and clozapine has been observed in patients receiving concomitant paroxetine.
Carbamazepine: Elevated plasma anticonvulsant concentrations and clinical anticonvulsant toxicity following initiation of concomitant paroxetine treatment.
Renal Dose :
Dose in Renal Impairment GFR (mL/min)
| 30-50 | Dose as in normal renal function |
| 10-30 | 20 mg daily and titrate slowly |
| <10 | 20 mg daily and titrate slowly |
Dose in Patients undergoing Renal Replacement Therapies
| CAPD | Unlikely to be dialysed. Dose as in GFR<10 mL/min |
| HD | Not dialysed. Dose as in GFR<10 mL/min |
| HDF/High flux | Unknown dialysability. Dose as in GFR<10 mL/min |
| CAV/VVHD | Unknown dialysability. Dose as for GFR=10–30 mL/min |
Hepatic Dose :
Mild to moderate hepatic impairment: Dose adjustment guidelines are not available, dose adjustment may not be required, plasma levels do increase in hepatic impairment so caution should be taken, and levels should be monitored.
Severe hepatic impairment: decrease dose by 50% to 5 mg/day. Increase every 1-2 weeks by 5mg to a maximum dose of 25mg/day.