Doxepin For Sleep: How This Prescription Helps Tackle Insomnia

Doxepin is a prescription medicine used for insomnia. It works by affecting your body’s histamine receptors, which in turn improves your sleep-wake cycle.

There’s something especially infuriating about waking up in the middle of the night.

Often, you’ve spent most of the previous day in an exhausted haze, just waiting for the moment when you can finally crawl into bed. Your night even seemed to start well, slipping easily towards sleep.

Whether it was a noise, a need for the bathroom or just the stressed-out corner of your brain that thinks you don’t spend enough time thinking about how losing your job would hurt your finances, you find yourself suddenly unable to drift off into dreamland.

We often feel perfectly awake during moments like these, which is particularly exasperating when we spend our workdays in a groggy haze.

In all likelihood, you’ve heard of and have probably tried several different sleep aids. You may have even stopped using screens before bed, set up a white noise machine, and tried to make your room as dark as possible. All of these are good options to help with insomnia that can often lead to more restful nights.

But what about when none of these work and you still can’t sleep?

This may be a sign that you need to speak with your doctor about prescription sleep medication. And that conversation includes not only if a prescription is suitable for you, but which prescription is right for you.

One such medication that your healthcare provider may consider is Doxepin.


What Is Doxepin?

Doxepin, also referred to under the brand name Silenor, is in a class of FDA-approved medications known as tricyclic antidepressants. These are medications that help balance chemicals in the brain to relieve depression. They are some of the oldest modern antidepressants, having been around since the 1950s.

In larger doses, doctors prescribe this medication to treat major depressive disorder and anxiety disorders. Because this drug also has antihistamine properties (similar to Benadryl, but in this case stronger), it is also prescribed for chronic hives.

However, doctors have found that, when prescribed in smaller doses, Doxepin is also a treatment option for those who can’t sleep. In fact, it’s been found to be especially helpful for those who have trouble staying asleep through the entirety of the night.

In studies, this medication had very little effect in helping patients fall asleep. Its benefit was helping patients with sleep maintenance, duration, and efficiency.

Doxepin is a non-controlled substance and is not considered addictive. And according to a National Institutes of Health study, this medication is safe for both short-term and long-term insomnia.


How Does Doxepin Work?

Unlike other antidepressants, Doxepin doesn’t act as a sedative to help you sleep.

Instead, it’s been shown to help control your circadian rhythm, the internal process that regulates your sleep-wake cycle. This is what tells you when it’s time to go to sleep each night and wake up each morning.

Histamine, a chemical produced throughout your body, plays a role in that regulation.

Think of histamine as part of your internal alarm clock. When histamine neurons are active, we feel bright, fresh, and awake. This is obviously helpful during the day, as it produces a well-rested, alert state.

It can drive you insane if it’s producing the same kind of productive, alert wakefulness at 3 AM, though.

Low doses of Doxepin bind to histamine H1 receptors in your brain and block them. This helps prevent histamine from shaking you awake in the middle of the night, telling you it’s time to start staring at the ceiling for a few hours.

Over the course of a 3-month clinical trial, a small dose of the drug helped participants with insomnia:

  • Sleep longer
  • Wake up at a more reasonable time
  • Feel well-rested and refreshed after sleeping

There is ongoing research to determine exactly how this medication influences sleep. One study found that 3 weeks of low-dose Doxepin treatment helped restore melatonin (another sleep-wake cycle regulator) to near-normal levels in insomnia patients.

In addition, sleep specialists believe that this medication may slow activity in the brain, helping us stay unconscious and get that much-needed sleep.


How Long Does Doxepin Stay In Your System?

The half-life for Doxepin is about 15 hours.

The low dose means that very little of your prescription is still active in your system after a good night of sleep.

And because it helps patients stay asleep, rather than fall asleep, you shouldn’t feel any residual tiredness when you wake up.

In fact, clinical trials found that low-dose Doxepin did not leave people feeling sedated or tired during the day. So, even patients who woke up with the medication in their systems did not feel daytime grogginess as a result.

Studies also found no withdrawal symptoms or rebound insomnia when patients stopped taking their prescription.


How Long Does Doxepin Work For Insomnia?

Doxepin takes roughly 30 minutes to kick in. That makes it a useful addition to your evening routine and sleep hygiene practices.

Evening routines are a key part of sending your body and mind signals that it’s time to get some rest and can help ease you into sleepiness. So if you’re taking Doxepin, try pairing it with:

  • Light stretches
  • Meditation
  • Reading
  • Journaling
  • Foam rolling
  • Listening to music
  • Having a light snack

The combination of medication with a soothing habit may even create a feedback loop that helps you wind down and sleep better, even when you stop taking Doxepin.

Because Doxepin improves your ability to stay asleep, you should also take it when you have 7-8 hours to sleep. Only take your prescription before bed. Never use this medication if you won’t be able to go to bed right away and stay asleep for at least 7 hours.

Never operate a vehicle or other heavy machinery after taking this drug.


What Dosage Of Doxepin Is Used For Insomnia?

The recommended dosage for Doxepin for insomnia depends on the individual. Height, weight, body composition, and sensitivity to the medication all play a role.

Most studies have shown that a small, 3mg-6mg dose of Doxepin is the most effective dosage for insomnia. This is significantly lower than the 25mg to 300mg daily dosage that doctors may prescribe for anxiety or depression.

You should discuss this with your doctor to make sure you’re taking the right dosage for your needs.

Be sure to take your prescription exactly as it’s been prescribed to you. To avoid any adverse effects, do not take more or less than your prescription without first consulting with your doctor.


What Are Doxepin’s Side Effects?

Patients taking Doxepin for insomnia who experience “sedation” as a side effect may actually appreciate it. Falling asleep faster, in addition to staying asleep longer, is surely a win-win for patients suffering from insomnia.

However, as with any other prescription drug, this medication may cause unwanted effects.

Some of these possible side effects may include:

  • Drowsiness
  • Dizziness
  • Hypotension (low blood pressure)
  • Cold symptoms (stuffy nose, runny nose, sneezing, sore throat)
  • Nausea
  • Vomiting
  • Diarrhea
  • Constipation
  • Loss of appetite
  • Dry mouth
  • Changes in body weight
  • Lack of coordination
  • Numbness
  • Tingly feeling
  • Irregular heartbeat
  • Disruptive dreams
  • Blurred vision
  • Headaches
  • Ringing sound in your ear
  • Increased sweating
  • Breast swelling
  • Decreased sex drive, impotence, or difficulty having an orgasm
  • Urinary retention or a decrease in frequency of urination

Please note this is not an exhaustive list of common side effects. Be sure to read through the drug information provided with your prescription for a full list.

Always be sure to let your doctor know if you’re experiencing these or any other adverse effects.

If you experience an allergic reaction, trouble breathing, or any other serious side effects, seek immediate medical attention.

Studies have shown that the side effects of Doxepin are greatly reduced at low doses. In fact, in one study, the emergence of side effects was “comparable to placebo.” You can also greatly reduce the risk of side effects by shortening your treatment duration (not taking it for too many weeks in a row).


Who Shouldn’t Use Doxepin?

Patients with certain medical conditions shouldn’t take Doxepin. These conditions include:

  • Glaucoma
  • Urinary problems
  • Kidney or liver disease

Patients should also avoid taking this medication while taking certain other drugs.

Doxepin can react poorly with:

  • Monoamine oxidase (MAO) inhibitor, or if you have stopped taking an MAO inhibitor within the past 14 days, including:
    • Isocarboxazid (Marplan)
    • Phenelzine (Nardil)
    • Selegiline (Eldepryl, Emsam, Zelapar)
    • Tranylcypromine (Parnate)
  • Methylene blue (Provayblue) or linezolid (Zyvox)
  • Cimetidine (Tagamet)
  • Medications for cough, cold, or allergies
  • Quinidine (in Nuedexta)
  • Sedatives
  • Selective serotonin reuptake inhibitors (SSRIs) such as:
    • Citalopram (Celexa)
    • Escitalopram (Lexapro)
    • Fluoxetine (Prozac, Sarafem, Selfemra, in Symbyax)
    • Fluvoxamine (Luvox)
    • Paroxetine (Brisdelle, Paxil, Pexeva)
    • Sertraline (Zoloft)
  • Other sleeping pills
  • Tolazamide
  • Tranquilizers

If you’re taking any other prescription or over-the-counter medicine, you should talk to a healthcare professional before taking Doxepin. They can tell you about your options and how to avoid drug interactions.

Also be sure to tell your doctor if you are currently pregnant, plan to become pregnant, or are breastfeeding.



Doxepin has been shown to be an effective solution for those who have trouble staying asleep throughout the night.

It is a prescription medication and should only be taken under the supervision of a doctor or sleep specialist. Always be sure to seek medical advice to determine if this or any other prescription sleep aid is right for you.