Patient Medication Information: uses, side effects, how to take - Isentress (Merck Canada, 400 mg, 600 mg)
What ISENTRESS®/ISENTRESS HD® is used for:
- ISENTRESS®/ISENTRESS HD® is a medicine that helps control Human Immunodeficiency Virus (HIV) infection, in combination with other antiretroviral medications.
- Your healthcare professional has prescribed ISENTRESS®/ISENTRESS HD® to help control your HIV infection.
- ISENTRESS® may be used to treat adults and children 6 years of age and older, weighing at least 25kg.
- ISENTRESS HD® may be used to treat adults and children weighing at least 40 kg.
How ISENTRESS®/ISENTRESS HD® works:
- ISENTRESS®/ISENTRESS HD® blocks an enzyme which the virus (HIV) needs in order to make more virus. The enzyme that ISENTRESS®/ISENTRESS HD® blocks is called HIV integrase.
The ingredients in ISENTRESS®/ISENTRESS HD® are:
Medicinal ingredient: Raltegravir potassium
Non-medicinal ingredients:
ISENTRESS® 400 mg raltegravir film-coated tablets:
calcium phosphate dibasic anhydrous, hypromellose 2208, lactose monohydrate, magnesium stearate, microcrystalline cellulose, poloxamer 407 (contains 0.01% butylated hydroxytoluene as antioxidant), sodium stearyl fumarate.
In addition, the film coating contains the following inactive ingredients: black iron oxide, polyethylene glycol 3350, polyvinyl alcohol, red iron oxide, talc and titanium dioxide.
ISENTRESS HD® 600 mg raltegravir film-coated tablets:
croscarmellose sodium, hypromellose 2910, magnesium stearate, microcrystalline cellulose.
In addition, the film coating contains the following inactive ingredients: black iron oxide, carnauba wax, hypromellose 2910, iron oxide yellow, lactose monohydrate, titanium dioxide, and triacetin.
ISENTRESS®/ISENTRESS HD® comes in the following dosage forms:
ISENTRESS® 400 mg film-coated tablets are available as pink, oval shaped, with “227” on one side.
ISENTRESS HD® 600 mg film-coated tablets are yellow, oval shaped tablets debossed with Merck logo and “242” on one side.
Do not use ISENTRESS®/ISENTRESS HD® if:
- You are hypersensitive to any of its ingredients (see The ingredients in ISENTRESS®/ISENTRESS HD® are:).
To help avoid side effects and ensure proper use, talk to your healthcare professional before you take ISENTRESS®/ISENTRESS HD®. Talk about any health conditions or problems you may have, including if you:
- Have any allergies.
- Have a history of muscle disorders (also known as rhabdomyolysis or myopathy).
Are pregnant or plan to become pregnant.
- If you take ISENTRESS®/ISENTRESS HD® while you are pregnant, talk to your healthcare professional about how you can be included in the Antiretroviral Pregnancy Registry.
Are breastfeeding or plan to breastfeed.
- It is recommended that HIV-infected women should NOT breastfeed their infants. This is because their babies could be infected with HIV through their breast milk.
- Talk with your healthcare professional about the best way to feed your baby.
Other warnings you should know about:
- ISENTRESS®/ISENTRESS HD® does not cure HIV infection or AIDS.
- It is very important that you stay under the care of your healthcare professional during treatment with ISENTRESS®/ISENTRESS HD®.
Tell your healthcare professional about all the medicines you take, including any drugs, vitamins, minerals, natural supplements or alternative medicines.
The following may interact with ISENTRESS®/ISENTRESS HD®:
Tell your healthcare professional especially if you take:
Antacids (medicines used to help treat heartburn) containing aluminum, magnesium and calcium carbonate.
- Certain antacids like those containing aluminum and/or magnesium are NOT recommended with ISENTRESS®.
- Atazanavir (antiretroviral medicine used to treat HIV).
- Rifampin (medicine used to treat tuberculosis).
- Tipranavir/ritonavir (antiretroviral medicines used to treat HIV).
How to take ISENTRESS®/ISENTRESS HD®:
Usual dose:
Take ISENTRESS®/ISENTRESS HD® by mouth, with or without food.
ISENTRESS®/ISENTRESS HD® must be used with other anti-HIV medicines.
Do NOT switch between the film-coated tablet, or different strengths, or stop your treatment without talking with your healthcare professional first.
Adult
Take one 400 mg tablet twice daily or two 600 mg tablets once daily as directed by your healthcare professional.
Children
Your child’s healthcare professional will tell you the right dose and type of ISENTRESS® based on your child’s weight.
Take ISENTRESS® or ISENTRESS HD® exactly as prescribed by your healthcare professional.
The different dosage forms and strengths for ISENTRESS® are not interchangeable so:
- a) Use only the 600 mg tablet for the 1200 mg once daily dose.
- b) Use only the 400 mg tablet for the twice daily dose of 400 mg.
Be sure to keep a supply of your anti-HIV medicines.
- When your ISENTRESS®/ISENTRESS HD® supply starts to run low, get more from your healthcare professional.
- Do not wait until your medicine runs out to get more.
IMPORTANT: Take ISENTRESS® exactly as your healthcare professional prescribed and at the right times of day because if you don’t:
- The amount of virus (HIV) in your blood may increase if the medicine is stopped for even a short period of time.
- The virus may develop resistance to ISENTRESS® and become harder to treat.
- Your medicines may stop working to fight HIV.
- The activity of ISENTRESS® may be reduced (due to resistance).
Overdose:
| If you think you, or a person you are caring for, have taken too much ISENTRESS®/ISENTRESS HD®, contact a healthcare professional, hospital emergency department, regional poison control centre or Health Canada’s toll-free number, 1-844 POISON-X (1-844-764-7669) immediately, even if there are no signs or symptoms. |
|---|
Missed dose:
If you miss a dose, take it as soon as you remember. If you do not remember until it is time for your next dose, skip the missed dose and go back to your regular schedule. Only take ISENTRESS® and ISENTRESS HD® as instructed.
ISENTRESS®/ISENTRESS HD® must be used with other anti-HIV medicines.
Possible side effects from using ISENTRESS®/ISENTRESS HD®:
These are not all the possible side effects you may have when taking ISENTRESS®/ISENTRESS HD®. If you have any side effects not listed here, tell your healthcare professional.
- nausea
- headache
- diarrhea
- fever
- vomiting
- fatigue
- dizziness
- difficulty sleeping
- cough
- rash
- tiredness
- upper respiratory tract infection
- inflammation of the nasal passages and throat
- bronchitis
- back pain
- depression
Additionally, while the medicine has been on the market, some further reactions have occurred:
- Depression and suicidal thoughts have been reported. If you develop these feelings, discuss this with your healthcare professional.
- Other side effects that have been reported include low blood platelet count, clumsiness and lack of coordination, rash with or without an increase in some white blood cells, severe skin reaction, liver failure. If you develop any of these reactions, discuss with your healthcare professional.
In some patients with advanced HIV infection (AIDS), signs and symptoms of inflammation from opportunistic infections may occur when combination antiretroviral treatment is started. Tell your healthcare professional immediately if you notice any symptoms of infection.
Contact your healthcare professional promptly if you experience unexplained muscle pain, tenderness, or weakness while taking ISENTRESS®/ISENTRESS HD®.
Contact your healthcare professional promptly if you develop a rash. Severe and life-threatening skin reactions and allergic reactions have been reported in some patients taking ISENTRESS®/ISENTRESS HD®.
Changes in your immune system (Immune Reconstitution Inflammatory Syndrome) can happen when you start taking HIV medicines. Your immune system may get stronger and begin to fight infections that have been hidden in your body for a long time, or you could develop an autoimmune disease in which your immune system reacts against your own body (e.g. Grave’s disease (which affects the thyroid gland), Guillain-Barre syndrome (which affects the nervous system) or polymyositis (which affects the muscles) and it may develop at any time, sometimes months later after the start of HIV therapy). Sometimes symptoms can be severe, so if you develop high temperature (fever), joint or muscle pain, redness, rash, swelling, or fatigue or any new symptoms contact your healthcare professional right away.
Serious side effects and what to do about them
| Frequency/Side Effect/Symptom | Talk to your healthcare professional | Stop taking this drug and get immediate medical help | |
|---|---|---|---|
| Only if severe | In all cases | ||
| Uncommon | |||
| Severe skin reactions and allergic reactions: occasionally life-threatening, with symptoms such as rash, itching or hives on the skin, swelling of the face, lips, tongue or other parts of the body, shortness of breath, wheezing or trouble breathing | ✓ | ||
| Persistent fatigue | ✓ | ||
| Lack of white blood cells: frequent infections such as fever, severe chills, sore throat or mouth ulcers | ✓ | ||
| Lack of red blood cells: tiredness, headaches, being short of breath when exercising, dizziness and looking pale | ✓ | ||
| Severe chest pain | ✓ | ||
| Stomach problems: pain, nausea, vomiting, heartburn | ✓ | ||
| Liver disease: liver disease with nausea, vomiting, loss of appetite, feeling generally unwell, fever, itching, yellowing of the skin and eyes, and dark coloured urine | ✓ | ||
| Kidney disease: nausea, loss of appetite and weakness, pass little or no urine, breathlessness | ✓ | ||
| Depression, suicidal thoughts and actions | ✓ | ||
| Shaking | ✓ | ||
| Speech disorders | ✓ | ||
| Disturbance in attention | ✓ | ||
If you have a troublesome symptom or side effect that is not listed here or becomes bad enough to interfere with your daily activities, tell your healthcare professional.
Reporting side effects
You can report any suspected side effects associated with the use of health products to Health Canada by:
NOTE: Contact your health professional if you need information about how to manage your side effects. The Canada Vigilance Program does not provide medical advice. |
Storage:
Store ISENTRESS® and ISENTRESS HD® at room temperature (15°C–30°C).
ISENTRESS® 400 mg tablets: Keep the desiccant in the bottle.
ISENTRESS HD® 600 mg tablets: Store in the original package with the bottle tightly closed. Keep the desiccant in the bottle to protect from moisture.
Keep ISENTRESS®/ ISENTRESS HD® and all medicines out of the reach and sight of children.
If you want more information about ISENTRESS®/ISENTRESS HD®:
- Talk to your healthcare professional.
- Find the full product monograph that is prepared for healthcare professionals and includes the Patient Medication Information by visiting the Health Canada Drug Product Database website (Drug Product Database: Access the database); the manufacturer’s website www.merck.ca; or by calling 1-800-567-2594.
Date of Authorization: 2026-10-20
® Merck Sharp & Dohme LLC. Used under license.
© 2011, 2026 Merck & Co., Inc., Rahway, NJ, USA and its affiliates. All rights reserved.
† All other trademarks are the property of their respective owner(s).