Isentress (Raltegravir): Uses, Dosing, Side Effects & How It Works

Isentress and Isentress HD (raltegravir) are HIV-1 integrase strand transfer inhibitors used with other antiretroviral agents to treat HIV-1 infection in adults and in pediatric patients who meet weight/age criteria.

What Isentress Is Used For

• Treatment of HIV-1 infection in adults as part of a combination antiretroviral regimen
• Pediatrics: Isentress indicated from 2 years of age and ≥7 kg; Isentress HD indicated for patients weighing ≥40 kg

Therapy selection and the background regimen should be guided by resistance testing and clinical judgment.

 

Dosing (General Information)

• Adults & adolescents ≥12 years: Isentress 400 mg twice daily
• Once-daily option (HD): Isentress HD 1200 mg total daily dose (two 600 mg tablets once daily) for patients weighing ≥40 kg who are treatment-naïve or virologically suppressed on 400 mg BID. Do not substitute 400 mg tablets to create a 1200 mg once-daily dose
• Pediatrics 2–<12 years: weight-based chewable tablets (25 mg, 100 mg) up to 300 mg twice daily
• Administration: May be taken with or without food
• Missed dose: Take as soon as possible; if near time for next dose, skip the missed dose and resume schedule

 

Available Forms & Strengths

• Isentress film-coated tablets: 400 mg (twice daily)
• Isentress HD film-coated tablets: 600 mg (two tablets once daily)
• Isentress chewable tablets: 25 mg and 100 mg (pediatric, twice daily)

Formulations have different pharmacokinetic profiles and are not interchangeable (e.g., do not combine 400 mg tablets to substitute for 600 mg HD dosing).

 

Common Side Effects

Frequently reported effects include:

• Insomnia, headache, dizziness
• Nausea, fatigue

Severe skin and hypersensitivity reactions (e.g., rash with systemic symptoms) have been reported—stop the drug and seek urgent care if these occur.

 

Important Interactions

• Antacids: Aluminum/magnesium-containing antacids can reduce raltegravir levels; coadministration with Isentress HD 1200 mg once daily is not recommended. Calcium carbonate may be acceptable with 400 mg BID per prescriber guidance
• Rifampin (UGT1A1 inducer): For 400 mg BID, adult dosage during rifampin coadministration may be adjusted (e.g., 800 mg BID). Once-daily HD with strong inducers is not recommended
• Atazanavir/tipranavir-ritonavir and other agents: May alter exposure; certain combinations with HD once-daily are not recommended. Review with your prescriber

 

Pregnancy, Breastfeeding & Special Populations

• Pregnancy: Use only if potential benefit justifies potential risk; discuss enrollment in an antiretroviral pregnancy registry
• Breastfeeding: Breast-feeding is generally not recommended for women with HIV; discuss infant feeding with your clinician
• Geriatrics: Use caution; consider comorbidities and concomitant therapies

 

Isentress Alternatives & Generic Options

• Generic raltegravir: Same active ingredient as Isentress
• Other ART options: May include other INSTIs, NNRTIs, PIs, and combination products; choice depends on resistance testing, tolerability, and guideline-concordant regimens

 

Lower Your Cost (For U.S. Patients)

If Isentress is expensive locally, Americans can order brand Isentress or generic raltegravir from Canada for personal use with a valid U.S. prescription. Consider a 3-month supply to reduce per-tablet cost and shipping frequency. Orders typically ship to U.S. residential addresses as a 90-day personal-use supply.

 

How to Buy from Canada (Step-by-Step)

1. Get a valid U.S. prescription for Isentress (raltegravir)
2. Send your prescription: Your clinic can fax to 1-833-209-3704 or you can upload your prescription
3. Choose brand or generic: Select Isentress/Isentress HD or generic raltegravir and the correct strength
4. Consider a 3-month supply: Buying more can reduce your per-tablet cost
5. Shipping: Orders ship to U.S. residential addresses (typically within 1–2 weeks), up to a 90-day supply

 

When to Seek Medical Help

• Severe or uncontrollable rash, fever, or signs of hypersensitivity
• Signs of severe skin reaction (e.g., blistering, mucosal lesions)
• Any unusual or concerning symptoms after starting a new ART regimen

 

References

Official monograph and full product information: Isentress / Isentress HD Product Monograph (Merck Canada)

Disclaimer: This page is for educational purposes and does not replace medical advice. Always consult your HIV specialist before starting or changing antiretroviral therapy.

Ready to order? Start here: Buy Isentress / Raltegravir from Canada

Legal and Safety Information

Information on this page is provided for general educational purposes and should not replace advice from a licensed healthcare professional. Some U.S. patients choose to source medications such as Isentress or generic raltegravir through licensed Canadian prescription referral services to help reduce costs. Medications dispensed by Canadian pharmacies are Health Canada–approved and intended for personal use only. Always follow your prescriber’s instructions and consult your healthcare provider with any questions about your treatment.

Isentress is usually taken orally with or without food, as prescribed by your doctor—typically once or twice daily depending on the formulation. Swallow the tablets whole with water and take them at the same time each day for best results. Consistent daily use is important to maintain effective viral suppression and prevent HIV resistance.