Doxepin oral capsule interactions: A detailed guide

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Overview

This article describes possible interactions with doxepin oral capsule. Interactions can cause a drug to have a different effect on the body than expected. Interactions can occur due to medications, alcohol, or certain health conditions.

Doxepin comes as a capsule that you’ll swallow. It’s also available as an oral liquid solution, an oral tablet, and a topical cream. The interactions and uses of doxepin may vary depending on the form you’re prescribed.

Doxepin comes as a capsule that you’ll swallow. It’s also available as a tablet and a liquid solution that you swallow.

Boxed warning: Risk of suicidal thoughts and behaviors

Doxepin has a boxed warning for the risk of suicidal thoughts and behaviors. A boxed warning is the most serious warning from the Food and Drug Administration (FDA).

See the end of this article for more information about this warning.

Other drugs and doxepin

The drugs in the list below may interact with doxepin oral capsule. This article doesn’t include all drugs that may interact with doxepin.

Drug classes or drugs that may interact with doxepin oral capsule include:

• antipsychotic drugs:
  • drug examples: fluphenazine, pimozide
  • what might happen: can cause long QT syndrome (changes in the heart’s electrical signals, which can lead to serious and life threatening heart rhythm problems)
• benzodiazepines:
  • drug examples: clonazepam (Klonopin), alprazolam (Xanax)
  • what might happen: can cause sedation (slowed brain activity)
• antihistamines, including those used in combination cold products:
  • drug examples: brompheniramine, chlorpheniramine
  • what might happen: can increase the risk of side effects of doxepin and the antihistamine
• decongestants:
  • drug examples: phenylephrine, pseudoephedrine
  • what might happen: can increase the risk of side effects of the decongestant
• catechol-O-methyl transferase (COMT) inhibitors:
  • drug examples: entacapone (Comtan), tolcapone (Tasmar)
  • what might happen: can cause sedation
• MAOIs:
  • drug examples: selegiline (Emsam, Zelapar), phenelzine (Nardil)
  • what might happen: can increase the risk of serotonin syndrome (a serious side effect that causes high levels of serotonin in the body)
• opioids:
  • drug examples: codeine, hydrocodone
  • what might happen: can cause sedation
• cimetidine (Tagamet):
  • what might happen: can increase the risk of side effects of doxepin
• linezolid (Zyvox):
  • what might happen: can increase the risk of serotonin syndrome
• ozanimod (Zeposia):
  • what might happen: can increase the risk of serotonin syndrome
• safinamide (Xadago):
  • what might happen: can increase the risk of serotonin syndrome

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When to avoid doxepin

Certain health conditions or other factors could increase some risks with doxepin oral capsule. Because of this, doctors may not prescribe doxepin in these cases. These health conditions or other factors are called contraindications.

Here’s a list of contraindications for doxepin oral capsule:

• Glaucoma. If you have glaucoma, taking doxepin oral capsule may cause a sudden increase in pressure inside your eye.
• Urinary retention. If you have urinary retention, taking doxepin oral capsule may prevent you from completely emptying your bladder.
• Linezolid. If you take linezolid (Zyvox), taking doxepin oral capsule can increase the risk of serotonin syndrome.
• MAOIs. If you take an MAOI, taking doxepin oral capsule can raise the risk of serotonin syndrome.
• Ozanimod. If you take ozanimod (Zeposia), taking doxepin oral capsule can increase the risk of serotonin syndrome.
• Pimozide. If you take pimozide, taking doxepin oral capsule can cause long QT syndrome.
• Safinamide. If you take safinamide (Xadago), taking doxepin oral capsule can increase the risk of serotonin syndrome.
• Past allergic reaction to doxepin or similar drugs. If you’ve ever had an allergic reaction to doxepin oral capsule, taking it again may cause a life threatening allergic reaction. This can also occur if you ever had an allergic reaction to similar drugs, including amoxapine and loxapine.

Before you start taking doxepin, tell your doctor if anything listed above relates to you. They can recommend whether you should take doxepin.

Alcohol and doxepin

Doxepin oral capsule is known to interact with alcohol.

Taking doxepin oral capsule and drinking alcohol may cause:

• sedation
• psychomotor impairment or retardation (weakened communication between the brain and muscles, which may affect your movements, speech, and regular activities)

If you drink alcohol, talk with your doctor about whether it’s safe to consume it while taking doxepin oral capsule.

Other interactions and doxepin

Interactions can occur with supplements, foods, vaccines, and some lab tests. Below you can learn whether doxepin oral capsule has these interactions. 

The information below doesn’t include all other possible interactions with doxepin.

Doxepin and supplements

Before taking doxepin oral capsule, tell your doctor and pharmacist about any herbs you take, as well as vitamins and supplements. Doing so may help you avoid interactions.

Doxepin oral capsule may interact with quinine. This supplement is used for leg cramps. Taking doxepin and quinine may lead to long QT syndrome.

Doxepin oral capsule may interact with melatonin. This supplement is used for sleep. Taking doxepin and melatonin may cause sedation.

If you have questions about interactions that may affect you, talk with your doctor or pharmacist.

Doxepin interactions and herbs

Doxepin oral capsule may interact with ephedra, also known as “ma huang.” This herb is used for athletic performance, allergies, weight loss, and congestion. Taking doxepin and ephedra may lead to dangerously high blood pressure.

Doxepin oral capsule may interact with St. John’s Wort. This herb is used for depression, anxiety, and sleep problems. Taking doxepin and St. John’s Wort may lead to serotonin syndrome. It may also prevent doxepin from working effectively.

Doxepin oral capsule may interact with valerian. This herb is used for depression, anxiety, and sleep problems. Taking doxepin and valerian may lead to sedation.

Because of this, ask your doctor or pharmacist before using any of these products while taking doxepin oral capsule.

Doxepin interactions and vitamins

Doxepin oral capsule isn’t known to interact with any vitamins. But this doesn’t mean interactions with vitamins can’t happen or won’t be identified later.

Because of this, ask your doctor or pharmacist before using any of these products while taking doxepin oral capsule.

Doxepin and food

Doxepin oral capsule isn’t known to interact with foods. But this doesn’t mean interactions with foods can’t happen or won’t be identified later.

Because of this, talk with your doctor or pharmacist about what foods you should avoid while taking doxepin oral capsule.

Doxepin and vaccines

Doxepin oral capsule isn’t known to interact with any vaccines. But this doesn’t mean interactions with vaccines can’t happen or won’t be identified later.

Because of this, talk with your doctor or pharmacist before receiving any vaccines while taking doxepin oral capsule.

Doxepin and lab tests

Doxepin oral capsule isn’t known to interact with lab tests. But this doesn’t mean interactions with lab tests can’t happen or won’t be identified later.

Because of this, talk with your doctor or pharmacist before having any tests while taking doxepin oral capsule.

Doxepin and cannabis or CBD

Studies of cannabis (commonly called marijuana) and cannabis products have been shown to interact with doxepin. Cannabidiol (CBD) is an example of a cannabis product.

Taking doxepin and cannabis or CBD may lead to increased levels of doxepin in your body. This may increase the severity and frequency of side effects, including sedation.

Before you take doxepin, tell your doctor and pharmacist if you use cannabis. Doing so may help prevent possible interactions.

Note: Cannabis is illegal at a federal level but is legal in many states to varying degrees.

Health factors and doxepin

Certain medical conditions or other health factors may increase the risk of interactions with doxepin oral capsule. Keep in mind that interactions could lead to side effects or affect how well the drug works. Before taking doxepin, tell your doctor about your health history. They’ll determine whether doxepin is right for you.

These health conditions or other factors might interact with doxepin oral capsule:

• bipolar disorder
• glaucoma
• kidney problems
• liver disease
• trouble urinating
• smoking tobacco
• pregnancy or breastfeeding
• past allergic reaction to doxepin or similar drugs, including amoxapine and loxapine
• past suicidal thoughts or behaviors*

* Doxepin has a boxed warning for suicidal thoughts and behaviors. A boxed warning is the most serious warning from the FDA. For more details, see the “Boxed warning for doxepin” section below.

Preventing doxepin interactions

You may be able to help avoid certain interactions with doxepin oral capsule. Before taking this drug, you may want to discuss possible interactions with your doctor and pharmacist.

Things to consider include:

• Whether you drink alcohol or use cannabis.
• Other medications and herbs you take, as well as vitamins and supplements. Your doctor or pharmacist can help you fill out a medication list.
• What to do if you’re prescribed a new drug while taking doxepin oral capsule.

Taking doxepin exactly as prescribed can also help prevent interactions.

What to ask your doctor

If you have questions about doxepin and possible interactions, talk with your doctor.

Questions you may want to ask your doctor include:

• Does my risk of interactions depend on my dosage of doxepin?
• Should I tell you if I start taking another medication or supplement during my doxepin treatment?
• Could I still take doxepin even if it interacts with a health condition I have?

Boxed warning for doxepin

Doxepin has a boxed warning for the risk of suicidal thoughts and behaviors. A boxed warning is the most serious warning from the FDA.

Antidepressants, including doxepin, may raise the risk of suicidal thoughts and behaviors in children and people younger than 25 years. This risk is highest during the first few months of treatment and with dosage changes.

Due to this risk, your doctor will closely monitor you for new or worsening symptoms. They’ll also ask family and caregivers to watch for them. Symptoms may include changes in thoughts, feelings, behaviors, or mood.

To learn more, talk with your doctor.

Note: Doxepin is only approved for use in adults and children ages 12 years and older.

Suicide prevention

If you or someone you know is in crisis and considering suicide or self-harm, please seek support:

• Call the 988 Suicide and Crisis Lifeline at 988.
• Text HOME to the Crisis Text Line at 741741.
• Not in the United States? Find a helpline in your country with Befrienders Worldwide.
• Call 911 or your local emergency services number if you feel safe to do so.

If you’re calling on behalf of someone else, stay with them until help arrives. You may remove weapons or substances that can cause harm if you can do so safely.

If you are not in the same household, stay on the phone with them until help arrives.

Disclaimer: Optum Perks has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.