Doxepin: Drug Effects, Side Effects, Dosage and Uses

Products

Doxepin is commercially available in many countries in capsule form (Sinquan) and has been approved since 1968.

Structure and properties

Doxepin (C₁₉H₂₁NO, M_r = 279.4 g/mol) is present in drugs as doxepin hydrochloride, a white crystalline powder that is readily soluble in water. It is a dibenzoxepin derivative.

Effects

Doxepin (ATC N06AA12) has antidepressant, depressant, antianxiety, anticholinergic, and antihistamine properties. Effects are attributed in part to inhibition of the reuptake of neurotransmitters such as norepinephrine into presynaptic neurons. Sleep-promoting effects are due to selective antagonism at histamine H1 receptors (low dose, 3 to 6 mg).

Indications

For the treatment of anxiety disorders and depression.

In some countries:

In low doses for the treatment of sleep disorders (Silenor).
As a cream for the treatment of itching in atopic dermatitis or lichen simplex chronicus (prudoxin).

Dosage

According to the professional information. The capsules can be taken once a day due to the long half-life of up to 24 hours. However, it is also possible to divide them into several doses.

Contraindications

Hypersensitivity
Glaucoma
Tendency to urinary retention
Combination with MAO inhibitors

For complete precautions, see the drug label.

Interactions

Doxepin is a substrate of CYP2D6 and corresponding interactions may occur. Other drug-drug interactions have been described with MAO inhibitors, guanethidine, antihypertensives, cimetidine, alcohol, central depressant drugs, and tolazamide.

Adverse effects

The most common potential adverse effects include dry mouth and drowsiness.