Explanation

Efavirenz (also called Sustiva) is a type of anti-retroviral medicine called a non-nucleoside reverse transcriptase inhibitor (NNRTI). NNRTIs help to fight HIV by reducing the amount of the virus in your blood.

What does efavirenz do?

Efavirenz helps control your HIV infection by preventing the HIV virus from making more copies of itself.

What does it look like?

Efavirenz comes in different forms, and your doctor will decide which one is best for you. There are:

Hard capsules that you swallow. These will be dark yellow and white, or just dark yellow - it depends which dose you get

Dark yellow tablets that you swallow

A clear liquid that you swallow. This will either be slightly yellow or have no colour at all.

When do I have to take it?

If you're taking the tablets or the capsules it's important that you take your efavirenz every day on an empty stomach. This means 1 hour before food or 2 hours after food. Make sure you don't chew or crush your tablets or capsules. If you're taking the liquid, you can take it with or without food.

It is usually best to take your efavirenz before bed, in case it makes you feel dizzy. Your doctor should also give you other medicines to take for your HIV, as well as efavirenz. It's very important that you also take these, and don't just take efavirenz by itself.

But what if I don't feel like taking it?

It's really important that you take your efavirenz every day, even if you don't feel like it or if you're feeling better. If you don't, the HIV virus can make more copies of itself in your blood.

If you don't want to take efavirenz for some reason, you must talk to your doctor about it, BUT don't stop taking it unless he or she says it's okay.

What should I do if I forget to take it?

If you forget to take your efavirenz, then you should take it as soon as you remember if it's not much later than you would normally take it. If it's close to the time you would take your next dose, then forget your missed dose and take the next dose as usual.

It's important that you don't take twice as much to make up for the dose you missed - remember the three D's - DON'T DOUBLE DOSE!

How much do I use?

Your doctor will decide exactly how much efavirenz you will need. This will depend on how old you are and what other medicines you're taking. It's very important that you take exactly the amount your doctor has told you to take, to help your immune system fight your HIV.

What are the most likely side effects I might get if I take efavirenz?

You are unlikely to get side effects while you're taking efavirenz, but if you do they may be serious. You should stop taking efavirenz straight away and tell your doctor if you notice a rash on your skin with blistering or a fever, as this can be quite dangerous.

There are other side effects you could possibly get in the first couple of days you start taking efavirenz, but these will usually go away after 2 to 4 weeks. If you're worried, it's best to speak to your doctor. The things to look out for are:

feeling dizzy

having trouble sleeping

feeling drowsy

having trouble concentrating

strange dreams

You should also tell your doctor immediately if you notice any of these side effects:

sore stomach

diarrhea (runny poo)

nausea (feeling sick)

vomiting (being sick)

feeling tired

swelling anywhere on your body or any signs of infection (like a runny nose, a sore throat, a fever)

changes in where your body fat is, for example your legs look skinny but you're bigger around your tummy

if you're feeling sad, aren't enjoying things you used to, or if you're having thoughts about hurting yourself

headaches

What other side effects might I get?

The other side effects that can happen after taking efavirenz are very unusual, so you're not likely to get them. Some of these can be serious though, so it's important for you and the adult looking after you to look out for them, just in case.

Tell your doctor straight away if you get:

blurred vision

sore upper abdomen

pain in your bones, or can't move your arms and legs as much, stiff joints and muscle spasms

yellowing of your skin or eyes

feeling angry or seeing or hearing things that aren't really there

Is it safe for me to be taking efavirenz?

Before you start taking efavirenz, you should tell your doctor about any medical problems you know you have, including any allergies, or if you have had any serious problems in the past.

It's especially important to tell your doctor if you have any of the things on the list below:

Lapp lactase deficiency or glucose-galactose malabsorption

allergy to efavirenz

liver disease

seizures

mental illness

kidney problems

Is it ok for me to take efavirenz if I'm already taking other medicines?

Let your doctor know if you're taking, or have recently taken, any other medicines, even herbal medicines or ones you got from the pharmacy without a prescription. It's especially important for you to tell him or her if you're taking any medicines that are in the list below:

antibiotics

voriconazole, itraconazole or posaconazole

astemizole or terfenadine

bepridil

cisapride

ergot alkaloids for example, ergotamine, dihydroergotamine, ergonovine, and methylergonovine

midazolam

pimozide

St. John's wort

carbamazepine or phenytoin

sertraline

atorvastatin, pravastatin, simvastatin

cyclosporine, sirolimus or tacrolimus

It's also very important that you tell your doctor about any other HIV medications you are taking, so that he or she can decide if it's safe for you to also take efavirenz.

What if I have any more questions?

If you have any other questions, you can ask your doctor, or you can join the Medikidz forums and talk to other people with HIV who are taking efavirenz.