Amitriptyline Drug Interactions

Amitriptyline is the active ingredient in a type of anti-depressant medication that is sometimes prescribed to people with chronic low back pain.  The dose for this usage (which is called "off-label prescribing"), is generally much lower than the dose given for depression. Amitriptyline is currently only available in the generic form; in the U.S., it had previously been manufactured by AstraZeneca under the brand name Elavil, but Elavil is now discontinued.

If you are taking other medications in addition to amitriptyline, you should discuss them in detail with your prescribing doctor. According to the website Drugs.com, over 2000 drugs may interact with amitriptyline, creating the potential for more than 500 major and 1400 moderate interactions.

Discuss Your Other Drugs With Your Doctor Before Taking Amitriptyline

When you have this important conversation with your doctor, be sure to mention not only other prescriptions and over the counters you take, but recreational substances, herbal and/or dietary supplements, as well.

The following list may get you thinking about what to say to your doctor before taking amitriptyline. (Note: this is by no means an exhaustive list.)

• Tell her about your alcohol intake.  Alcohol in combination with amitriptyline is a known risk for moderate drug interactions; possible side effects include uneven heartbeats, drowsiness, confusion, agitation, vomiting, blurred vision, seizures and more. 
• Mention any herbal supplements you take.  St. John's Wort, for example, is an herbal medication used by some to treat mild to moderate depression.  Taking it in combination with amitriptyline may affect your liver functioning.
• Be transparent with your doctor about any illegal drug use in which you engage.  As with some prescribed medications, over the counter drugs and herbal or dietary supplements, when amitriptyline interacts with illegal substances, the result can harm your health.
• Be very sure to tell your doctor if you have used an MAO inhibitor.  MAO inhibitors include furazolidone (Furoxone), isocarboxazid (Marplan), phenelzine (Nardil), rasagiline (Azilect), selegiline (Eldepryl, Emsam, Zelapar), or tranylcypromine (Parnate). Note: MAO inhibitors should NOT be taken with amitriptyline.

• Other things to mention to your doctor before taking amitriptyline include: Antacids, birth control pills and female hormones, intake of grapefruit and/or grapefruit juice, kaolin or pectin, sleeping pills, antihistamines and other allergy medications, cold and flu medications, weight loss drugs or appetite suppressants, muscle relaxants (i.e.,cyclobenzaprine), and prescription pain medications, such as morphine, codeine, or tramadol. 

Some interactions between amitriptyline and other drugs may elevate the amount of amitriptyline in your blood, possibly leading to increased side effects.  Here is a partial list of medications that may interact with amitriptyline in this way:

• drugs taken for an irregular heartbeat, as well as other heart medications
• disulfiram, a medication used to help people with alcoholism avoid from drinking
• atropine, phenobarbital, and similar drugs
• blood thinners, such as Warfarin
• bromocriptine
• cimetidine, a heartburn/ulcer medication, as well as metoclopramide
• high blood pressure clonidine, as well as labetalol
• delavirdine, as well as other drugs used to treat HIV infection
• diphenoxylate, a diarrhea medication
• the chemotherapy drugs imatinib and procarbazine
• Parkinson's medications, such as levodopa
• Alzheimer's medications, such as donepezil, galantamine, and tacrine
• epilepsy and seizure medication
• some antibiotics
• thyroid hormones, such as levothyroxine
• SSRI medications

As you can see, the list of possible drug interactions with amitriptyline is pretty long. In fact, this is nowhere near a complete list.  As I mentioned at the beginning of this article, the Drugs.com website says that over 2000 drugs and brand names can interact with amitriptyline.  That's why It is imperative that you discuss your other medications with your doctor and not solely rely on the information in this article.

By being thorough and honest with your doctor about the other medications you take, you can assist her in determining if amitriptyline is a safe and effective choice for managing your chronic back pain.