Avifanz
Generic Name
Efavirenz
Manufacturer
Square Pharmaceuticals Ltd.
Country
Bangladesh
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Price Details
Current market pricing information
| Variant | Unit Price | Strip Price |
|---|---|---|
| avifanz 600 mg tablet | ৳ 200.00 | ৳ 2,000.00 |
Description
Overview of the medicine
Avifanz (Efavirenz) is an antiretroviral drug used in combination with other agents to treat Human Immunodeficiency Virus type 1 (HIV-1) infection in adults and children.
Uses & Indications
Dosage
Adults
600 mg orally once daily, preferably at bedtime on an empty stomach.
Elderly
No specific dosage adjustment for elderly patients, but caution is advised due to potential age-related decrease in renal/hepatic function.
Renal_impairment
No dosage adjustment required for patients with renal impairment.
How to Take
Administer orally once daily, preferably on an empty stomach, at bedtime to minimize central nervous system (CNS) side effects. Taking with a low-fat meal may be acceptable.
Mechanism of Action
Efavirenz is a non-nucleoside reverse transcriptase inhibitor (NNRTI) that acts by directly binding to the reverse transcriptase enzyme of HIV-1, blocking its RNA-dependent and DNA-dependent DNA polymerase activities, thereby inhibiting viral replication.
Pharmacokinetics
Onset
Viral load reduction typically observed within weeks of initiating therapy.
Excretion
Mainly excreted in feces (16-61% as unchanged drug or metabolites); less than 1% excreted unchanged in urine.
Half life
Approximately 52-76 hours (single dose), 40-52 hours (multiple doses).
Absorption
Well absorbed after oral administration; peak plasma concentrations reached in 3-5 hours. Absorption is increased with a high-fat meal.
Metabolism
Primarily hepatic metabolism via CYP2B6 and CYP3A4 to hydroxylated metabolites, which are then glucuronidated. Efavirenz induces its own metabolism.
Side Effects
Contraindications
- Hypersensitivity to Efavirenz or any component of the formulation.
- Severe hepatic impairment.
- Co-administration with certain drugs highly dependent on CYP3A4 for clearance (e.g., voriconazole, midazolam, triazolam, ergot derivatives, cisapride, pimozide, St. John's wort).
Drug Interactions
Statins
Efavirenz can alter plasma concentrations of statins; dose adjustment of statin may be necessary.
Rifampicin
Efavirenz may decrease rifampicin concentrations; dosage adjustment of rifampicin may be needed.
Voriconazole
Efavirenz significantly decreases voriconazole plasma concentrations; co-administration is contraindicated.
Hormonal Contraceptives
Efavirenz may decrease the efficacy of hormonal contraceptives; alternative or additional methods of contraception should be used.
Storage
Store below 30°C in a dry place, protected from light and moisture. Keep out of reach of children.
Overdose
Symptoms of overdose typically involve increased CNS effects. Management is supportive. Gastric lavage and activated charcoal may be used. Hemodialysis is unlikely to be beneficial as Efavirenz is highly protein bound.
Pregnancy & Lactation
Pregnancy Category D. Efavirenz has been associated with neural tube defects in some animal studies and isolated human cases. It should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus, and generally avoided in the first trimester. Breastfeeding is not recommended for HIV-infected mothers to prevent postnatal HIV transmission and due to potential drug exposure to the infant.
Side Effects
Contraindications
- Hypersensitivity to Efavirenz or any component of the formulation.
- Severe hepatic impairment.
- Co-administration with certain drugs highly dependent on CYP3A4 for clearance (e.g., voriconazole, midazolam, triazolam, ergot derivatives, cisapride, pimozide, St. John's wort).
Drug Interactions
Statins
Efavirenz can alter plasma concentrations of statins; dose adjustment of statin may be necessary.
Rifampicin
Efavirenz may decrease rifampicin concentrations; dosage adjustment of rifampicin may be needed.
Voriconazole
Efavirenz significantly decreases voriconazole plasma concentrations; co-administration is contraindicated.
Hormonal Contraceptives
Efavirenz may decrease the efficacy of hormonal contraceptives; alternative or additional methods of contraception should be used.
Storage
Store below 30°C in a dry place, protected from light and moisture. Keep out of reach of children.
Overdose
Symptoms of overdose typically involve increased CNS effects. Management is supportive. Gastric lavage and activated charcoal may be used. Hemodialysis is unlikely to be beneficial as Efavirenz is highly protein bound.
Pregnancy & Lactation
Pregnancy Category D. Efavirenz has been associated with neural tube defects in some animal studies and isolated human cases. It should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus, and generally avoided in the first trimester. Breastfeeding is not recommended for HIV-infected mothers to prevent postnatal HIV transmission and due to potential drug exposure to the infant.
Frequently Asked Questions
Common questions about this medicine
Pack Sizes
Shelf Life
Refer to the expiry date on the packaging, typically 2-3 years from manufacturing date.
Availability
Available in pharmacies nationwide
Approval Status
FDA approved (1998), DGDA approved
Patent Status
Generic available
WHO Essential Medicine
YesClinical Trials
Extensive clinical trials have demonstrated the efficacy and safety of Efavirenz in the treatment of HIV-1 infection, leading to its global approval and inclusion in standard treatment regimens.
Lab Monitoring
- Liver function tests (LFTs) at baseline and periodically, especially in patients with pre-existing hepatic impairment.
- Lipid profile (cholesterol, triglycerides) at baseline and periodically.
- Viral load and CD4 cell count to monitor treatment efficacy.
- Glucose levels.
Doctor Notes
- Emphasize strict adherence to avoid development of drug resistance.
- Counsel patients on potential CNS side effects, especially during the first 2-4 weeks, and recommend taking the dose at bedtime on an empty stomach.
- Monitor liver function tests, lipid profiles, and counsel on safe contraception.
- Screen for psychiatric symptoms, especially in patients with a history of mental illness.
Patient Guidelines
- Take Avifanz exactly as prescribed, do not miss doses, even if you feel well.
- Report any severe rash, skin peeling, or signs of liver problems (yellowing skin/eyes, dark urine, abdominal pain) to your doctor immediately.
- Be aware of potential CNS side effects like dizziness, abnormal dreams, or mood changes, especially during the first few weeks of treatment.
- Use reliable barrier contraception (e.g., condoms) if you are a woman of childbearing potential, as Efavirenz can reduce the effectiveness of hormonal birth control and has potential for fetal harm.
Missed Dose Advice
If a dose is missed, take it as soon as possible. If it is almost time for the next dose, skip the missed dose and resume the regular dosing schedule. Do not double dose.
Driving Precautions
Efavirenz can cause dizziness, drowsiness, and impaired concentration, especially during the initial weeks of treatment. Patients should be advised to exercise caution when driving or operating machinery until they know how the drug affects them.
Lifestyle Advice
- Maintain a healthy and balanced diet.
- Avoid or limit alcohol consumption to minimize potential liver toxicity and CNS side effects.
- Practice safe sex to prevent HIV transmission.
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