Medically reviewed by Mary Lucas, RN
Written by Our Editorial Team
Last updated 10/22/2020
If you’ve recently been prescribed doxepin by your healthcare provider, or if you’re considering doxepin as a medication to treat depression, anxiety or insomnia, you may have questions related to how this medication works and what it does.
Below, we’ve provided expert answers to 15 of the most common questions about doxepin, from what this medication is used for to common side effects, dosages, brand names and more.
Doxepin is a prescription tricyclic antidepressant, and it’s used to treat conditions ranging from major depressive disorder to insomnia. Doxepin is a commonly prescribed medication in the United States, with millions of prescriptions written for it every year.
Doxepin comes in several different forms, including oral tablets, capsules and solutions, as well as a topical cream (used for hives only).
First approved in 1969, doxepin is sold under a variety of brand names depending on its intended use, including Silenor® for insomnia. Today, it’s widely available as a generic medication. In 2010, the FDA approved the use of doxepin as a treatment for adults with insomnia.
Doxepin is used to treat a range of conditions. As a tricyclic antidepressant, it’s often prescribed to treat major depressive disorder (MDD, or simply depression), and anxiety disorders. Doxepin is also commonly used at much lower doses to treat insomnia.
Topical doxepin, in cream form, is used to treat itching caused by skin conditions like lichen simplex chronicus and atopic dermatitis. Although it seems to have been largely phased out by more effective drugs, doxepin is also occasionally used to treat hives.
Yes. Studies of doxepin show that it’s an effective treatment for long-term, chronic insomnia and short-term difficulty sleeping. Some studies of doxepin have shown that it’s particularly effective as a treatment for insomnia in people who frequently wake up after falling asleep.
A 2013 scientific review of doxepin as an insomnia treatment looked at several studies and concluded that doxepin, at small doses of 3mg and 6mg, is well tolerated, non-habit forming and effective at managing both chronic and transient insomnia.
A 2014 review of doxepin use by elderly people with difficulty sleeping also found that doxepin was an effective treatment that, “significantly reduced waking after sleep onset and increased total sleep time.
Interestingly, doxepin appears to be effective even at a very low dose. In the 2014 study above, the researchers concluded that there were no significant differences in effectiveness between the 3mg and 6mg doses of doxepin.
A 2007 study even found that doses of doxepin as low as 1mg were effective at increasing total sleep time, reducing waking after sleep onset and improving sleep efficiency.
Put simply, scientific studies of doxepin show that it’s effective at treating insomnia. People with insomnia who used doxepin slept for longer, were less likely to wake up after falling asleep and typically experienced increased levels of sleep efficiency.
Doxepin is an antagonist of the H1 and H2 histamine receptors, which play a key role in the regulation of the body’s sleep-wake cycle.
Doxepin’s effect on these receptors may contribute to feelings of tiredness and improved sleep maintenance in people with insomnia.
Doxepin should be taken at least three hours after consuming a meal and within 30 minutes of bedtime. In the time after taking doxepin, you should limit your activities to those necessary to prepare to go to sleep.
Doxepin has a half-life of 15 hours, meaning each dose of the medication that you use will be halfway eliminated from your body after approximately 15 hours. A single 6mg dose of doxepin will reach its peak concentration approximately 3.5 hours after consumption.
Many older medications prescribed to treat insomnia, such as benzodiazepines or “Z-drugs” like zolpidem, are associated with early-morning drowsiness and sleeping pill “hangovers.”
For example, some users of Ambien (zolpidem) have reported feeling drowsy and less alert in the daytime after using the medication to fall asleep. In response to this, in 2013 the FDA lowered the starting dose of zolpidem-based sleep aids.
Several studies of doxepin have observed that these morning “hangover” effects don’t seem to occur when doxepin is used at low doses for insomnia.
For example, an independent review of doxepin from 2011 noted that doxepin does not cause next-day sedation at low doses. A 2013 review of doxepin for insomnia also noted that it does not cause next-day sedation — a distinct advantage over other insomnia medications.
It’s important to be aware that the sleep-inducing effects of doxepin last for several hours after you take the medication. This means that although doxepin does not cause next-day tiredness when used normally, it may cause you to feel drowsy if you only sleep for a short period.
To avoid daytime drowsiness, you should only use doxepin to treat insomnia if you plan to sleep for seven to eight hours immediately after taking the medication.
Like all medications, doxepin can cause certain side effects. The most common side effects of doxepin for insomnia include:
Upper respiratory tract infection
In rare cases, doxepin can cause serious side effects, including anxiety, suicidal thoughts, mania and behavioral changes.
It’s important to note that doxepin is prescribed in significantly higher doses for depression and anxiety than for insomnia. FDA trial data shows that serious side effects from doxepin are uncommon when the medication is used at the 3mg to 6mg dosage prescribed for insomnia.
Doxepin is a prescription-only medication, meaning you’ll need to speak to a healthcare professional and receive a prescription before you can purchase it.
Doxepin is sold as a generic medication under a range of brand names. In the United States, it’s commonly sold as Silenor® for insomnia and Sinequan® for depression and anxiety. The topical form is sold under the brand names Prudoxin® Cream and Zonalon®.
In other countries, doxepin may be sold under the following brand names in addition to Silenor® and Sinequan®:
Li Ke Ning®
The amount of doxepin contained in these medications can vary. The dosage of doxepin used to treat conditions like major depressive disorder is significantly higher than the typical dosage for insomnia. If you’re prescribed doxepin, follow the dosage provided by your healthcare provider.
As we mentioned above, doxepin is prescribed at a variety of different dosages to treat different conditions.
Doxepin is typically prescribed for insomnia at a dosage of 3mg to 6mg per night. When prescribed for major depressive disorder, anxiety and other conditions, doxepin is typically used at a higher dosage, often in the 75mg to 150mg per day range.
For mild depression or anxiety, doxepin may be prescribed at a lower dose, including dosages as low as 25mg to 50mg. The maximum doxepin dosage used for major depressive disorder and anxiety is 300mg per day.
Like other tricyclic antidepressants, doxepin has the potential to interact with other medications.
Several different drugs are known to interact with doxepin, with some being classed as major drug interactions.
Common medications that can interact with doxepin include certain MAOI (monoamine oxidase inhibitors) and SSRI (selective serotonin reuptake inhibitor) antidepressants. If you use an MAOI or have used one within the last two weeks, using doxepin may cause severe side effects.
Other medications that can potentially interact with doxepin include sleeping pills, narcotic pain medications, anxiety medications and medications used to treat seizures.
To avoid any potential drug interactions, it’s essential that you disclose all other medications that you currently use to your physician before using doxepin.
It is possible to overdose on doxepin. However, the dosage of doxepin that’s prescribed to treat insomnia is less than five percent of the maximum recommended dosage for this medication.
If you are concerned that you or someone you are with has taken an unsafe amount of doxepin, call your local emergency number or the national toll-free Poison Help hotline (1-800-222-1222) as soon as possible.
The U.S. National Library of Medicine’s MedlinePlus page for doxepin has more information on what to do in the event of a doxepin overdose.
Doxepin should not be combined with alcohol. Drinking alcohol after taking doxepin can result in increased feelings of drowsiness and reduced concentration, creating an increased risk of injury or accident.
Although both doxepin and zolpidem (the active ingredient in Ambient) are used to treat difficulty sleeping, they’re different medications with different effects on the body.
Zolpidem, the active ingredient in Ambien, is a hypnotic medication that’s primarily used to treat insomnia in people who find it difficult to fall asleep. It works for up to eight hours and can make falling asleep easier in people who frequently spend a long time away after going to bed.
Doxepin is an antidepressant medication. As an insomnia treatment, it’s typically used to assist people who frequently wake up after falling asleep.
Unlike zolpidem, which is commonly used to help people with insomnia fall asleep faster, study data tends to indicate that although doxepin increases sleep time and reduces nighttime waking, it doesn’t have a significant effect on the amount of time required to fall asleep.
Zolpidem and doxepin are both prescription medications. Based on your symptoms, your healthcare provider may recommend one medication over the other as a more effective treatment option.
If you find it difficult to get enough sleep, or find yourself waking up frequently during the night, doxepin could be an effective treatment option to help you manage your insomnia and benefit from longer, higher quality sleep.
Our guide to using doxepin to treat insomnia goes into more detail on how doxepin works as a sleep aid, its effects on the sleep-wake cycle and the benefits it may offer if you’re affected by insomnia.
If you’re considering doxepin for another condition, such as depression or anxiety, you can also learn more about it in our Doxepin 101 guide.