Class: Tricyclic Antidepressant
Dosage Forms. Capsule: 10 mg, 25 mg, 50 mg, 75 mg, 100 mg, 150 mg; Tablet: 3 mg, 6 mg; Solution: 10 mg/mL
Common FDA Label Indication, Dosing, and Titration.
1. Alcoholism, anxiety, depression: Very mild, 25-50 mg po daily, titrate to 300 mg po daily; Mild-moderate, 75 mg po daily, titrate to 300 mg po daily
2. Insomnia: Adults <65 y of age, 6 mg po daily hs; Adults 65 y of age and older, 3 mg po daily hs, titrate to 6 mg po daily hs
Off-Label Uses. None
MOA. Doxepin is a tricyclic antidepressant, which influences the adrenergic activity at the synapses where it prevents norepinephrine deactivation through reuptake into the nerve terminals. By binding to histamine receptor sites, it competitively inhibits the biological activation of histamine receptors. Antagonism of the H1 receptor is the most likely mechanism by which doxepin exerts its sleep maintenance effect.
Drug Characteristics: Doxepin
Medication Safety Issues: Doxepin
Drug Interactions: Doxepin
Adverse Reactions: Doxepin
Efficacy Monitoring Parameters. Improvement depression (depressed mood, suicidal thoughts or intent, change in appetite, lack of energy, change in sleep patterns, etc).
Toxicity Monitoring Parameters. Worsening of depression, suicidality, or unusual changes in behavior, especially at the initiation of therapy or with dosage increases or decreases. Change in ECG, monitor LFTs.
Key Patient Counseling Points. Avoid activities requiring mental alertness until drug effects are realized. Symptomatic improvement in depression may not be seen for a few weeks. Avoid abrupt discontinuation of drug. Do not drink alcohol.
Clinical Pearls. Safety and effectiveness not established in children. Also available in topical formulation for pruritus due to atopic dermatitis.