doxepin, Sinequan, Adapin
Omudhome Ogbru, PharmD
Omudhome Ogbru, PharmD
Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.
Medical and Pharmacy Editor:
GENERIC NAME: doxepin
BRAND NAME: Sinequan, Adapin
DRUG CLASS AND MECHANISM: Doxepin belongs to a class of drugs called tricyclic antidepressants (TCAs) that are used primarily to treat depression and anxiety. Other examples of TCAs include amitriptyline (Elavil), nortriptyline (Pamelor), desipramine (Norpramin), and several others. Depression is an all-pervasive sense of sadness and gloom. In some patients with depression, an imbalance in levels of neurotransmitters in the brain may be the cause of the depression. Neurotransmitters are chemicals that nerves use to communicate with each other. Neurotransmitters affected by doxepin include serotonin, norepinephrine, acetylcholine, and histamine. Doxepin may elevate mood by raising the levels of serotonin and norepinephrine. It also blocks the activity of acetylcholine and histamine. The FDA approved doxepin in March 1974.
GENERIC AVAILABLE: Yes
PREPARATIONS: Capsules: 10, 25, 50, 75, 100, 150 mg; Liquid: 10 mg/ml
STORAGE: Doxepin should be stored below 30 C (86 F) in a tight, light resistant container.
DOSING: The usual dose of doxepin is 75 to 300 mg daily administered at bedtime or in three divided doses. Doses greater than 300 mg daily are not more effective. Optimal improvement in depressive symptoms is seen after 2-3 weeks; anti-anxiety effects occur much sooner.
DRUG INTERACTIONS: Tricyclic antidepressants should not be used with monoamine oxidase inhibiting drugs, for example, tranylcypromine (Parnate), because high fever, convulsions, and even death may occur from such combinations.
Cimetidine (Tagamet) increases the breakdown of doxepin by the liver and can increase doxepin blood levels, possibly causing side effects from doxepin.
PREGNANCY: There are no adequate studies of doxepin use in pregnant women.
NURSING MOTHERS: It is not known if doxepin is secreted in breast milk. There is one report of apnea (cessation of breathing) and drowsiness occurring in a nursing infant whose mother was taking doxepin.
SIDE EFFECTS: The most common side effect of doxepin is drowsiness. Drowsiness improves as therapy continues. Other side effects associated with doxepin include blurred vision, urinary retention (difficulty urinating), dry mouth, constipation, weight gain or loss, and low blood pressure when rising from a sitting position (orthostatic hypotension). Rash, hives, rapid heart rate, seizures, and hepatitis are rare side effects. Doxepin also can cause elevated pressure in the eyes of some patients with glaucoma. If antidepressants, including doxepin, are discontinued abruptly, symptoms such as dizziness, headache, nausea, and changes in mood may occur. Such symptoms of withdrawal may occur even when a few doses of antidepressant are missed. Therefore, it is recommended that the dose of antidepressant be reduced gradually when therapy is discontinued.
Antidepressants increased the risk of suicidal thinking and behavior in short-term studies in children and adolescents with depression and other psychiatric disorders. Anyone considering the use of any antidepressant in a child or adolescent must balance this risk with the clinical need. Patients who are started on therapy should be closely observed for clinical worsening, suicidal thinking or behavior, and unusual changes in behavior.
Reference: FDA Prescribing Information
Last Editorial Review: 2/19/2009
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