Doxepin

Indications

Doxepin is used for: Anxiety disorders, Depression, Insomnia

Adult Dose

Oral Depression/Anxiety Adult: Initiate at low dose (25 mg/day); gradually titrate upward every 5-7 days Dosage range: 25-300 mg/day PO, up to 150 mg/day as single dose If dose exceeds 150 mg/day, divide q12hr Hepatic impairment: Use lower dose and adjust gradually for depression; Insomnia (Silenor) Sleep maintenance 3-6 mg PO within 30 minutes before bedtime; not to exceed 6 mg/day Hepatic impairment/debilitated patients: 3 mg PO within 30 minutes before bedtime Elderly Insomnia Sleep maintenance Starting dose: 3 mg PO within 30 minutes before bedtime May increase to 6 mg PO HS if clinically indicated Depression/Anxiety Lower initial dose (ie, 10 mg/day) and adjust gradually; 10-25 mg PO qHS May increase by 10-25 mg increments q3Day for inpatients and weekly for outpatients if tolerated

Child Dose

<12 years old: Not recommended

Renal Dose

Administration

May be taken with or without food.

Contra Indications

Hypersensitivity; mania, glaucoma, neonates (topical); lactation.

Precautions

Epilepsy, CV disease, pregnancy, history of urinary retention, glaucoma; gradual withdrawal. May impair ability to drive or operate machinery. Lactation: Enters breast milk; not recommended (AAP states "may be of concern")

Pregnancy-Lactation

Interactions

Methylphenidate may increase plasma doxepin levels. Potentially Fatal: Potentiates hypertensive action of sympathomimetics. Increased anticholinergic effects with MAOIs. Additive CNS effects with anticholinergics, CNS depressants and alcohol.

Adverse Effects

Side effects of Doxepin : Sedation, fatigue, weakness, lethargy,Dry mouth,Constipation,Blurred vision,Headache,Agitation,Insomnia,Anxiety,Nausea, vomiting,Sweating,Confusion, extrapyramidal symptoms (EPS), dizziness, paresthesia,Orthostatic hypotension, ECG changes, tachycardia,Increased LFTs,Tinnitus,Sexual dysfunction,Rash,Seizure,Agranulocytosis,Thrombocytopenia,Eosinophilia,Leukopenia,SIADH

Mechanism of Action

Doxepin inhibits serotonin and norepinephrine re-uptake by the presynaptic neuronal membrane increasing its synaptic conc in the CNS.