From the Guidelines
The active ingredient in Unisom SleepTabs is doxylamine succinate, while Unisom SleepGels contain diphenhydramine hydrochloride. The original Unisom SleepTabs contain doxylamine succinate (25mg), which is an antihistamine that causes drowsiness by blocking histamine receptors in the brain. However, Unisom SleepGels contain diphenhydramine hydrochloride (50mg), another antihistamine that works similarly. Both ingredients are effective for short-term treatment of insomnia, typically helping you fall asleep about 30 minutes after taking them. These medications work by reducing brain activity and blocking signals that keep you awake. Side effects may include dry mouth, dizziness, and morning grogginess. It's essential to use these sleep aids only for short periods (generally less than two weeks) as they can lose effectiveness over time and aren't intended for treating chronic insomnia, as suggested by 1. If you're pregnant, diphenhydramine is generally considered safer than doxylamine, though you should always consult with a healthcare provider before taking any medication during pregnancy. Some key considerations for the use of these medications include:
- Potential for sedation, performance impairment, and anticholinergic effects, as noted in 1
- Importance of using the lowest effective dose and for the shortest duration necessary, as recommended in 1
- Need for caution in older adults and those with comorbid conditions, as advised in 1
- Availability of alternative treatments, such as cognitive behavioral therapy for insomnia, as discussed in 1
From the FDA Drug Label
Active ingredient (in each tablet) Doxylamine succinate 25 mg The active ingredient in Unisom (doxylamine) is Doxylamine succinate. Key points:
- The active ingredient is Doxylamine succinate
- The dosage is 25 mg per tablet 2
From the Research
Active Ingredient in Unisom
- The active ingredient in Unisom is doxylamine, which is an antihistamine of the ethanolamine class 3.
- Doxylamine is used primarily as a sleep-inducing agent and is available without a prescription in some countries, including the Federal Republic of Germany 3.
- Doxylamine succinate is the chemically defined active ingredient in some sleeping medications, including Unisom 4, 5, 6.
Pharmacokinetics and Pharmacodynamics
- The pharmacokinetics and pharmacodynamics of doxylamine have been studied in various clinical trials, including a Phase I study of intranasal doxylamine in subjects with chronic intermittent sleep impairment 4.
- The study found that doxylamine pharmacokinetics were similar between intranasal and oral dosing, with no significant differences in maximum plasma concentration or area under the curve 4.
- Another study found that food intake did not affect the pharmacokinetics of doxylamine in healthy subjects 5.
Availability and Use
- Doxylamine is available over-the-counter (OTC) in various formulations, including tablets and nasal sprays 4, 6.
- It is commonly used for the short-term management of insomnia and is also used in combination with other ingredients in OTC sinonasal products 6, 7.
- Doxylamine has been suggested as a potential treatment for maintenance insomnia, particularly in the last third of the night 7.