Fluoxetine
Mechanism :
Fluoxetine 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 :
- Depression
- Obsessive compulsive disorder
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 :
Major depression:
7 years or younger: Safety and efficacy have not been established.
8 years to 18 years: Initial dose: 10 to 20 mg orally once daily. The dose should be increased to 20 mg/day after a week.
Obsessive Compulsive Disorder:
6 years or younger: Safety and efficacy have not been established.
7 years to less than 18 years: Initial dose: 10 mg orally once daily.
Adolescents and higher weight children: After 2 weeks at 10 mg/day, the dose should be increased to 20 mg/day. A dose range of 20 to 60 mg/day is recommended.
Adverse Effect :
Anxiety, headache, nervousness, drowsiness, sedation, insomnia, tremor, jitteriness, dizziness, fatigue, myoclonus, tics, migraine, sleep abnormalities, dyskinesia, acute dystonic reactions, worsening of Parkinson’s disease, stuttering, paresthesia, seizures, and cognitive dysfunction, nausea and diarrhea, dry mouth, constipation, stomatitis, dyspepsia, upper gastrointestinal bleeding, neuroleptic malignant syndrome, transient psychosis, hypomania, mania, delusions, paranoid reaction, agitation, depersonalization syndrome, platelet dysfunction, bradycardia prolongation of QT interval, ventricular arrhythmia including Torsade de Pointes, hypotension, hypersensitivity.
Interaction :
Lithium: There have been reports of both increased and decreased lithium levels when lithium was used concomitantly with fluoxetine.
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 fluoxetine 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 fluoxetine.
Carbamazepine: Elevated plasma anticonvulsant concentrations and clinical anticonvulsant toxicity following initiation of concomitant fluoxetine treatment.
Renal Dose :
Dose in Renal Impairment GFR (mL/min)
| 20-50 | Dose as in normal renal function |
| 10-20 | Dose as in normal renal function |
| <10 | Use low dose, or on alternate days and increase according to response |
Dose in Patients undergoing Renal Replacement Therapies
| CAPD | Not dialysed. Dose as in GFR<10 mL/min |
| HD | Not dialysed. Dose as in GFR<10 mL/min |
| HDF/High flux | Not dialysed. Dose as in GFR<10 mL/min |
| CAV/VVHD | Not dialysed. Dose as in GFR= 10–20 mL/min |
Hepatic Dose :
Fluoxetine is extensively metabolized by the liver and excreted by the kidneys. A lower dose, e.g., alternate day dosing, is recommended in patients with significant hepatic dysfunction.