Other uses
A 2010 review found that topical doxepin is useful to treat itchiness.A 2010 review of treatments for chronic hives found that doxepin had been superseded by better drugs but was still sometimes useful as a second-line treatment. Contraindications
Known contraindications include:
Hypersensitivities to doxepin, other TCAs, or any of the excipients inside the product used
Glaucoma
A predisposition to developing urinary retention such as in benign prostatic hyperplasia
Use of monoamine oxidase inhibitors in last 14 days

Pregnancy and lactation
Its use in pregnant and lactating women is advised against, although the available evidence suggests it is unlikely to cause negative effects on fetal development. The lack of evidence from human studies, however, means it is currently impossible to rule out any risk to the fetus and it is known to cross the placenta. Doxepin is secreted in breast milk and neonatal cases of respiratory depression in association with maternal doxepin use have been reported. Side effects
Doxepins side effects profile may differ from the list below in some countries where it is licensed to be used in much smaller doses (viz., 3 mg and 6 mg).
A positive dose–response relationship on sleep measures was observed for doses of doxepin between 1 and 6 mg in clinical studies, whereas the incidence of adverse effects remained constant across this dose range in both young and older adults. However, the incidence of adverse effects appeared to increase with longer treatment duration. A dose of doxepin as low as 1 mg/day was found to significantly improve most of the assessed sleep measures, but unlike the 3 and 6 mg/day doses, was not able to improve wake time during sleep. This, along with greater effect sizes with the higher doses, was likely the basis for the approval of the 3 and 6 mg doses of doxepin for insomnia and not the 1 mg dose.At very low doses, doxepin has not shown discontinuation or withdrawal effects nor rebound insomnia. Sustained effectiveness without apparent tolerance was demonstrated in clinical studies of up to 12 weeks duration. This appears to be in contrast to over-the-counter antihistamines like diphenhydramine and doxylamine and all other first-generation antihistamines, which are associated with rapid development of tolerance and dependence (by day 3 or 4 of continuous dosing) and loss of hypnotic effectiveness. It is for this reason that, unlike doxepin, they are not recommended for the chronic management of insomnia and are advised for only short-term treatment (i.e., 1 week).