Doxepin

What is doxepin?

Doxepin (daak·suh·pn) belongs to a class of drugs called tricyclic antidepressants (TCAs). This class of drugs affects the brain chemicals serotonin and norepinephrine.

Doxepin works as a serotonin-norepinephrine reuptake inhibitor (SNRI). Those two neurotransmitters (chemical messengers) are often out of balance in individuals with anxiety disorders and depression.

Tricyclic antidepressants manage and treat clinical depression, also known as major depressive disorder (MDD).

Doxepin is only available with a doctor’s prescription.

Doxepin is available in the following forms:

Capsules (the oral capsule form only comes as a generic drug)

• 10mg

• 25mg

• 50mg

• 75mg

• 100mg

• 150mg

Tablets (brand name Silenor)

• 3mg

• 6mg

Oral Concentrate (generic drug)

• 10mg/ml

Topical Cream (brand name Prudoxin)

• Cream, 5%  

What is doxepin used to treat?

Doxepin is used mainly to treat depression and anxiety.

It is also used in low doses to treat insomnia (disordered sleep). 

The topical form of doxepin is sometimes prescribed short-term in low doses to relieve itching and various forms of dermatitis (skin inflammation) because it works as an antihistamine.

How do you take doxepin?

Take doxepin exactly as prescribed by your doctor. Do not start or stop taking doxepin without consulting with your doctor. Do not take more or less than your prescribed dosage. 

When used orally, doxepin can be taken with or without food.

For the treatment of anxiety and depression, the initial doxepin dosage is typically 75mg, once a day. 

For those with mild conditions, doxepin may be prescribed at 25–50mg per day. 

The maximum dose is 150mg daily. 

A maintenance dose of doxepin is usually 75–150mg, once a day. The 150mg form is unsuitable for initial treatment (that level is intended for maintenance therapy only). Your doctor will inform you if and when it is suitable to make any changes to your medication. For the treatment of insomnia in adults, an initial dose ranges from 3–6mg, once a day. The maximum dose is 6mg a day.

Using doxepin for the treatment of depression and anxiety is not recommended for children. The suitability of doxepin for the treatment of insomnia in children should be determined only by a doctor.

Liquid solution

Doxepin liquid solution should be taken using the dropper (pipette) provided. It will be clearly marked to assist you with measuring the correct amount. Get one at your local pharmacy if a dropper isn’t included with your medication. A common household spoon is not accurate enough for measuring doxepin.

Dilute your liquid doxepin solution in 120ml (4 oz.) of water, milk, or juice before taking it. Do not add doxepin to carbonated drinks. 

Only dilute and mix this solution directly before taking it. Do not prepare it ahead of time.

Tablet

The tablet should not be taken within three hours of a meal. Otherwise, it may not work properly. In addition, it may make you drowsy, so it should be taken approximately 30 minutes before sleeping. 

When taking the tablet form, plan on having a full night’s sleep as the medication may make you feel sedated if you wake up too soon.

Seeing results

When doxepin starts to work depends on the condition being treated. For the treatment of depression, symptoms may start to improve after two to three weeks of taking doxepin. For the treatment of anxiety, results may be sooner.

Remember that even if you are feeling well, you should not stop taking doxepin without direction from your prescribing doctor.

Potential side effects of doxepin

Several side effects may occur while taking doxepin. Common side effects include:

• Dizziness

• Drowsiness

• Dry mouth

• Constipation

• Blurred vision

• Trouble urinating

• Vomiting

• Nausea

• Upset stomach

• Weight gain

• Changes in food taste

• Swelling, rash

• Increased blood pressure

• Increased or decreased sex drive

• Vision changes

• Increase in breast size

• Swollen testicles

• Hair loss

 Doxepin can also cause serious side effects, such as:

• Yellowing of the eyes or skin

• Unusual bruising or bleeding

• Fast heartbeat

• Seizures

• Worsening depression with the following symptoms:

  • Suicidal thoughts

  • Suicide attempts

  • Worsened or new symptoms of anxiety

  • Panic attacks

  • Agitated or restless feelings

  • Insomnia

  • Aggressive, violent, or angry actions

  • Acting on dangerous impulses

  • Mania (an extreme increase in talking and activity)

  • Other mood or behavioral changes

• Urinary symptoms:

  • Incomplete bladder emptying

  • Painful urination

  • Sudden urge to urinate

  • Bloating or pain in the lower belly

• Allergic reactions with the following symptoms:

  • Rash

  • Swelling of the face, throat, or tongue

  • Itching

These side effects are severe, and most require immediate medical attention. Contact your doctor or seek medical attention immediately if you experience these side effects.

Long-term use of doxepin

Prolonged use of low-dose doxepin is generally safe, as long as you follow your doctor’s prescribed dosage.

Missed doses

Never take a double dose of doxepin to make up for a missed one. Consider setting a reminder to help you remember to take doxepin on schedule.

 Overdoses

Symptoms of doxepin overdose can include the following:

• Confusion

• Agitation

• Drowsiness

• Irregular heartbeat

• Trouble concentrating

• Muscle stiffness

• Clumsiness

• Shivering

• Weak pulse

• Convulsions or seizures

• Vomiting

• Hallucination

• Increase in pupil size

• Fever

• Lower than usual body temperature

• Slow or shallow breathing

• Coma

Even if some of these symptoms aren’t causing you immediate distress, they could indicate doxepin toxicity. Seek medical attention or call 911 immediately.

What to discuss with your doctor before taking doxepin

Before taking doxepin, these are some essential topics to discuss with your doctor:

• Allergies you have or past allergic reactions to medications (especially doxepin).

• Medications you currently take (prescribed or non-prescribed), including vitamins and supplements.

• If you have taken monoamine oxidase inhibitors (MAOIs) in the past 14 days.

• Other medical conditions particularly: bipolar disorder, glaucoma, and urinary problems.

• Whether you are pregnant or trying to get pregnant. 

• Whether you are currently breastfeeding or planning to breastfeed. 

• Upcoming medical or dental procedures (or plans to have one). 

• Whether or not you consume alcohol, how much, and how frequently.

Stopping doxepin

Do not suddenly stop taking doxepin without your doctor’s instruction to do so. The risk of withdrawal symptoms is higher in patients that have been using doxepin long-term.

Withdrawal symptoms may include:

• Nausea

• Tiredness

• Headache

• Abdominal pain

• Vomiting

• Fainting 

• Irritability or agitation

• Trouble sleeping

• Seizures

• Anxiety

If you have concerns about continuing your use of doxepin, talk to your doctor.  If they advise you to stop taking doxepin, they will likely prescribe you a gradually decreased dosage to help reduce or avoid withdrawal symptoms.

Doxepin and pregnancy

Doxepin for treatment of depression falls under US FDA pregnancy Category B. Reproductive studies of doxepin in animals did not show a risk to the fetus. However, there are no well-controlled human studies yet.

Taking doxepin while breastfeeding is not recommended. Doxepin is known to pass into breast milk and may cause unwanted effects on the nursing infant.

The use of doxepin is only recommended when the benefits outweigh the possible risks.

Doxepin and interactions with other drugs

Doxepin can interact with both prescription and nonprescription drugs, as well as herbal supplements. These interactions can change how doxepin works, increasing the risk of side effects or preventing doxepin from working properly.

To reduce the possibility of dangerous interactions talk to your doctor about any medications you currently take (or might take) while on doxepin.

Drugs known to interact with doxepin include (but are not necessarily limited to):

Monoamine oxidase inhibitors

MAO inhibitors used to treat clinical depression or Parkinson’s disease, such as selegiline (Eldepryl, Emsam), phenelzine (Nardil), and isocarboxazid (Marplan, Marplon, Enerzer) should not be taken with doxepin. Together they overload the brain with serotonin, which can cause psychosis or even be fatal.

Stomach ulcer drugs

The drug cimetidine (Tagamet) can increase the amount of doxepin in the body.

Antifungal drugs

Fluconazole (Diflucan), voriconazole (Vfend), and terbinafine (Lamisil) can increase the amount of doxepin in the body.

Antiarrhythmic or antimalarial drug

Quinidine (Cardioquin, Quinaglute) and dronedarone (Multaq) can have the opposite of the desired effect and increase irregular heartbeat symptoms.

Kidney drugs

Chronic kidney disease drugs like cinacalcet (Sensipar) increase the amount of doxepin in the body.

Blood glucose lowering drugs

Combining tolazamide (generic) for type 2 diabetes while on doxepin can cause dangerously low blood sugar levels.

Alcohol

Drinking alcohol while taking doxepin can increase feelings of confusion or drowsiness.

Allergy information

Severe allergic reaction, also known as anaphylaxis is a possibility for those who take doxepin. 

Symptoms of anaphylaxis include:

• Lightheadedness

• Difficulty breathing 

• Swelling of the face and lips

• Hives

• Wheezing

• Confusion

• Anxiety

• Elevated heart rate

• Clammy skin

If you experience symptoms of a severe allergic reaction, seek immediate medical attention or call 911. 

Clinical trial history

Doxepin gained US FDA approval in 1969 for the treatment of major depressive disorder (MDD).

After six controlled trials, low-dose doxepin was approved to treat insomnia in 2010.

Doxepin is not yet approved for the treatment of migraines or nerve pain, but it is sometimes prescribed off-label (therapeutically).

Tips and advice for taking doxepin

• Avoid alcohol while on doxepin. Consuming alcohol can increase your risk of side effects.

• Doxepin can make you drowsy. Avoid driving, using machinery, or doing activities that require full attention.

• Doxepin may cause sun sensitivity (photosensitivity) so it is imperative to take protective measures to prevent burning, such as wearing sunscreen every day and avoiding direct exposure or tanning.

• As with all medication, keep doxepin stored safely away from children.

• Not all pharmacies stock doxepin. Call ahead if you need to refill your prescription.