Estiva 600mg Efavirenz Tablet

Q1: What is Estiva 600mg (Efavirenz) used for?

Estiva 600mg is an NNRTI used as the third agent in combination HIV therapy with a dual NRTI backbone. Once the most prescribed HIV drug globally, it remains widely used in resource-limited settings and for patients stable on existing regimens.

Q2: How does Efavirenz work to suppress HIV?

Efavirenz binds directly to HIV-1 reverse transcriptase at a non-competitive allosteric site, distorting the enzyme's shape and blocking its activity. This non-nucleoside mechanism complements NRTI activity, providing dual reverse transcriptase inhibition.

Q3: Why must Estiva be taken at night on an empty stomach?

Efavirenz's distinctive CNS side effects (dizziness, vivid/disturbing dreams) are experienced by 50%+ of patients. Taking it at bedtime means most of these effects occur during sleep. An empty stomach is important because high-fat meals increase absorption by ~50%, significantly worsening CNS effects.

Q4: How long do the CNS side effects last?

Most patients adapt to Efavirenz's CNS effects within 2–4 weeks with consistent dosing. Dizziness and disturbing dreams typically resolve, though some patients continue to have vivid dreams. If effects are severe or psychiatric symptoms develop (depression, suicidal ideation), medical evaluation is required immediately.

Q5: What are the most common side effects of Estiva 600mg?

CNS effects (dizziness, vivid dreams, impaired concentration), rash (in ~10–27% of patients, usually mild and self-resolving), nausea, diarrhea, and elevated liver enzymes are most common.

Q6: What serious psychiatric risks are associated with Efavirenz?

Efavirenz is associated with psychiatric adverse events including depression, anxiety, psychosis, suicidal ideation, and aggression in approximately 1–2% of patients. Patients with pre-existing psychiatric conditions are at higher risk. Report any mood changes to your doctor.

Q7: Does Efavirenz cause rash and how serious is it?

Rash occurs in about 10–27% of patients, typically in the first 2 weeks and usually mild. Severe rash with blistering, involvement of mouth/eyes, or Stevens-Johnson syndrome is rare (<1%) but requires immediate stopping of Estiva and emergency care.

Q8: What drug interactions affect Efavirenz?

Efavirenz is a mixed CYP3A4 inducer and inhibitor — it reduces levels of many drugs including some statins, contraceptives, and antiretrovirals. Rifampicin requires dose increase to 800mg. Check all interactions before starting any new medication.

Q9: Is Estiva safe during pregnancy?

Efavirenz was previously contraindicated in the first trimester based on animal data. Human epidemiological data have not confirmed neural tube defect risk, and Efavirenz is now considered an option in pregnancy after counselling about the theoretical risk.

Q10: What monitoring is required during Estiva therapy?

CD4 count and viral load at baseline and every 3–6 months. Liver function tests (particularly relevant in HBV/HCV co-infected patients). Lipid monitoring for long-term use. Psychiatric symptom assessment at every visit.

Q11: How should Estiva 600mg be stored?

Store at room temperature away from light and moisture. Keep in original packaging out of reach of children.

Q12: Do I need a prescription for Estiva?

Yes. Efavirenz requires specialist HIV prescribing with assessment of psychiatric history, liver function, and complete drug interaction review before initiation.