What is Sustiva? Uses, Dosage, Side Effects & Safety Tips

Quick Takeaways

• Sustiva is the brand name for efavirenz, an antiretroviral used in HIV‑1 treatment.
• It’s taken once daily, usually at bedtime, with or without food.
• Common side effects include vivid dreams, dizziness, and rash; most are mild and short‑lived.
• Never combine Sustiva with certain antidepressants, rifampicin or St. John’s wort without doctor approval.
• If you notice severe rash, mood changes, or liver‑related symptoms, seek medical help immediately.

How Sustiva Works and Who Should Take It

Sustiva belongs to the non‑nucleoside reverse transcriptase inhibitor (NNRTI) class. In simple terms, it blocks an enzyme that HIV needs to copy itself, slowing the virus down and giving the immune system a chance to recover. The drug is approved for use in combination with other antiretrovirals, typically as part of a fixed‑dose regimen like Atripla.

The medication is prescribed for adults and children over three years old who are newly diagnosed with HIV‑1 or who need a change in their treatment plan because of resistance or side‑effects from other drugs. It’s not meant for HIV‑2, and pregnant women should discuss risks with their provider, as efavirenz has been linked to birth defects in early studies.

For most patients, Sustiva offers a convenient once‑daily dosing schedule and has become a staple in first‑line therapy worldwide, especially in low‑ and middle‑income countries where the cost is lower than many newer agents.

Dosage and Administration

The standard adult dose is 600mg (one 600mg tablet) taken once a day, preferably at bedtime. Taking it at night helps reduce the impact of dizziness and vivid dreams, two of the most frequently reported central‑nervous‑system (CNS) effects.

For children weighing 30kg or more, the same 600mg dose is used. For smaller children, dosing is weight‑based: 10mg per kilogram of body weight, rounded to the nearest tablet strength.

Here’s a quick checklist to make sure you’re taking it correctly:

1. Take the tablet with a full glass of water.
2. If you have a sensitive stomach, you can eat a small snack, but it’s not required.
3. Do not split, crush, or chew the tablet; the coating is designed for slow release.
4. Set a daily reminder - consistency is key for keeping viral load low.
5. Never miss more than two doses in a row without talking to your clinician.

If you forget a dose and it’s less than 12hours before the next scheduled dose, skip the missed tablet and continue as normal. Taking a double dose to “catch up” can increase the risk of side effects.

Side Effects and Management

Most people tolerate Sustiva well, but around 30‑40% experience at least one CNS side effect during the first few weeks. The good news is that they usually improve after the body adjusts. Below is a table that summarises the most common adverse events and their typical frequency.

If you develop a rash that spreads quickly, blisters, or is accompanied by fever, treat it as a medical emergency - some skin reactions can progress to Stevens‑Johnson syndrome, a rare but serious condition.

For CNS symptoms, many clinicians recommend a short “lead‑in” period where the dose is taken every other day for the first week, then switched to daily once tolerable. Always discuss any plan with your healthcare provider.

Interactions, Precautions, and FAQs

Sustiva is metabolised mainly by the liver enzyme CYP2B6. This means it can both affect and be affected by other drugs that use the same pathway. Below are the top culprits you should flag to your pharmacist or doctor:

• Rifampicin (used for TB) - can lower efavirenz levels, risking treatment failure.
• St. John’s wort - herbal supplement that also induces CYP enzymes, with a similar effect as rifampicin.
• Some antidepressants (e.g., fluoxetine, paroxetine) - may increase efavirenz concentrations, worsening CNS side effects.
• Azole antifungals (ketoconazole, fluconazole) - can raise efavirenz levels, requiring dose adjustment.

Precautions include:

• Baseline and periodic liver function tests, especially if you have hepatitis B or C.
• Pregnancy counseling - discuss risk‑benefit with your obstetrician.
• Screening for mental‑health conditions before starting, as the drug can exacerbate depression.

FAQ

1. Can I take Sustiva with food? Yes, it can be taken with or without meals. A light snack at night may help reduce stomach upset.
2. How long does it take to see viral suppression? Most patients achieve an undetectable viral load within 8‑12 weeks if adherence is >95%.
3. Is it safe to drink alcohol? Moderate alcohol is generally okay, but heavy drinking can worsen liver toxicity and CNS effects.
4. What should I do if I miss a dose? If it’s less than 12hours until the next dose, skip the missed one. Otherwise, take it as soon as you remember, then continue with the regular schedule.
5. Can I switch from another NNRTI to Sustiva? Yes, but a doctor should oversee a “wash‑out” period and monitor viral load closely during the transition.

When in doubt, always reach out to your HIV specialist. They can tailor the regimen, run necessary labs, and help you navigate any side‑effect puzzle.

Next Steps & Troubleshooting

After you’ve started Sustiva, keep a simple log:

• Date & time you take the tablet.
• Any new symptoms (sleep changes, mood, rash).
• Other medications or supplements added.

Bring this log to your follow‑up visits - it makes it easier for the clinician to spot patterns and adjust therapy quickly.

If you’re experiencing persistent side effects that interfere with daily life, ask your doctor about the possibility of switching to an integrase‑strand transfer inhibitor (INSTI) based regimen, which many patients find more tolerable.

Remember, the goal of any antiretroviral is to keep the virus suppressed forever. Consistency, open communication with your health team, and a proactive approach to side‑effects are the three pillars that keep you on track.