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
Pregnancy category: Not available
Lactation: Enters breast milk; not recommended (AAP states "may be of concern")
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.