Skip to content
My WebMD Sign In, Sign Up

rifampin Oral

Efavirenz/Rifampin

This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug or commencing any course of treatment.

Medical warning:

Moderate. These medicines may cause some risk when taken together. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.

How the interaction occurs:

Rifampin may speed up how quickly your body processes efavirenz.

What might happen:

The amount of efavirenz in your blood may decrease and it may not work as well.

What you should do about this interaction:

Let your healthcare professionals (e.g. doctor or pharmacist) know that you are taking these medicines together or if you have taken rifampin in the previous two weeks. Your doctor may want to change the amount of efavirenz you are taking, especially if you weigh 50 kg (110 lbs) or more. Your doctor also may want to check how your efavirenz is working.Your healthcare professionals may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.Reference:1.Sustiva (efavirenz) US prescribing information. Bristol-Myers Squibb Company August, 2012.

References:

See 31 Reviews for this Drug. - OR -

Review this Treatment

Find a Drug:

by name or medical condition or shape/color (Pill Identifier)

(for example: aspirin)

(for example: diabetes)

Pill Identifier

Learn about User Reviews and read IMPORTANT information about user generated content

Report Problems to the Food and Drug Administration
 
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Health Solutions From Our Sponsors

FDA Protect Your Health

Benzocaine and Babies: Not a Good Mix
Database Is One-Stop Resource on Kids' Medications
Explore our expanded FDA Center on WebMD.

Ask the pharmacist

Questions about medications? Get expert answers by video or live chat about allergies, pregnancy, sleep, and more.
See the Ask the Pharmacist event schedule.

Ask a Question

Popular Slideshows & Tools on WebMD

Previous Next
Tick attached to skin
Lyme Disease
Symptoms and treatments.
Woman sitting in front of UV lights
Psoriasis Treatment
Is yours working?
colon xray
Ulcerative Colitis
Get the facts.
MS Overview
Multiple Sclerosis
Recognizing symptoms.
Rheumatoid Arthritis and Osteoporosis: Exercising
Healthy Joints
Tips to keep them strong.
Engaged bathroom stall sign
Constipation Relief
Vacation tips.
nurse helping woman on crutches
Knee Surgery
How much time to recover?
Doctor with blood sample
CML Phases
Treatments to consider.
Close up of eye
Concentration Killers
What's robbing your focus?
fruit drinks
Brain Foods
Foods that can help you focus.
woman stretching
Living Healthy Guide
Must-see diet and fitness info.
mother with children in park
Baby to Teen
Parenting tips for every age.
» See all slideshows

Women's Health Newsletter

Find out what women really need.

WebMD the app

Get trusted health information. Whenever. Wherever... with your iPhone, iPad or Android.

Find Out More

IMPORTANT: About This Section and Other User-Generated Content on WebMD

The opinions expressed in WebMD User-generated content areas like communities, reviews, ratings, or blogs are solely those of the User, who may or may not have medical or scientific training. These opinions do not represent the opinions of WebMD. User-generated content areas are not reviewed by a WebMD physician or any member of the WebMD editorial staff for accuracy, balance, objectivity, or any other reason except for compliance with our Terms and Conditions. Some of these opinions may contain information about treatment or uses of drug products that have not been approved by the U.S. Food and Drug Administration. WebMD does not endorse any specific product, service, or treatment.

Do not consider WebMD User-generated content as medical advice. Never delay or disregard seeking professional medical advice from your doctor or other qualified healthcare provider because of something you have read on WebMD. You should always speak with your doctor before you start, stop, or change any prescribed part of your care plan or treatment. WebMD understands that reading individual, real-life experiences can be a helpful resource but it is never a substitute for professional medical advice, diagnosis, or treatment from a qualified health care provider. If you think you may have a medical emergency, call your doctor or dial 911 immediately.