Buy Sustiva

Sustiva

What is Sustiva?

Sustiva is a brand-name medication that contains the active ingredient efavirenz. Efavirenz belongs to the class of non-nucleoside reverse transcriptase inhibitors (NNRTIs) and is used as part of combination antiretroviral therapy for the management of HIV-1 infection. In Hong Kong, Sustaina is a prescription-only product regulated by the Drug Office of the Department of Health. It is supplied as an oral pill in two strengths: 200 mg and 600 mg.

How Sustiva Works in the Body

Efavirenz blocks the activity of HIV-1 reverse transcriptase, an enzyme the virus needs to copy its genetic material and replicate inside human cells. By binding to a specific site on the reverse transcriptase enzyme, efavirenz prevents the conversion of viral RNA into DNA, halting the infection cycle. The drug is absorbed well after oral administration, reaching peak plasma concentrations within 3-5 hours. It is extensively metabolized in the liver, primarily by the cytochrome P450 enzyme CYP2B6, and has a relatively long half-life of about 40-55 hours, allowing once-daily dosing.

Conditions Treated with Sustiva

Sustiva (efavirenz) is approved for use in combination with other antiretroviral agents to treat HIV-1 infection in adults. It is typically prescribed as part of a three-drug regimen that may include two nucleoside reverse transcriptase inhibitors (NRTIs) or an integrase inhibitor. The medication helps reduce viral load, increase CD4+ T-cell counts, and improve overall immune function, which can delay disease progression and reduce the risk of opportunistic infections.

Patient Suitability and Contraindications

Who may benefit from Sustiva?

• Adults diagnosed with HIV-1 infection who require a NNRTI component in their antiretroviral regimen.
• Patients with no contraindicating conditions and who can adhere to once-daily dosing.

Absolute contraindications

• Known hypersensitivity to efavirenz or any of the tablet’s inactive ingredients.
• Severe hepatic impairment (Child-Pugh class C).
• Pregnancy (efavirenz is classified as Category D/X due to teratogenic risk; it should be avoided unless no safer alternatives are available).

Relative contraindications

• Moderate hepatic dysfunction (Child-Pugh class A or B).
• Pre-existing psychiatric illness (e.g., depression, anxiety) because efavirenz can exacerbate CNS symptoms.
• Co-administration with potent CYP2B6 inducers or inhibitors without dose adjustment.

Special populations

• Pregnancy/Lactation: Efavirenz should be avoided during the first trimester; counseling on risks versus benefits is essential.
• Elderly: No specific dose adjustment is required, but clinicians should monitor liver function and mental health closely.
• Renal impairment: No dose change is needed because efavirenz is primarily metabolized hepatically.

Safety Profile: Side Effects and Interactions

Common Side Effects

• Central nervous system: dizziness, insomnia, vivid dreams, headache, and mild depression (often described as “common”).
• Gastrointestinal: nausea, abdominal pain, and loss of appetite.
• Dermatologic: mild rash or itching.

Serious Adverse Events

• Severe psychiatric reactions: suicidal ideation or severe depression; patients should seek immediate medical help if these occur.
• Severe rash: Stevens-Johnson syndrome or toxic epidermal necrolysis (rare but life-threatening).
• Hepatotoxicity: elevated liver enzymes or hepatitis; monitor liver function regularly.

Drug Interactions

• Major:
• Rifampin (induces CYP2B6) → reduces efavirenz plasma levels, possibly compromising efficacy.
• Azole antifungals (e.g., ketoconazole) → increase efavirenz levels, raising toxicity risk.
• Moderate:
• Protease inhibitors (e.g., ritonavir) can affect efavirenz metabolism; dose adjustments may be required.
• St. John’s wort (CYP2B6 inducer) → may lower efavirenz concentrations.

Food and Lifestyle Interactions

• Efavirenz can be taken with or without food; a high-fat meal may modestly increase absorption.
• Alcohol may intensify CNS side effects (dizziness, drowsiness).
• Patients should avoid operating heavy machinery until they know how efavirenz affects them.

If specific interaction data are unavailable, patients should always inform their healthcare provider of all concurrent medications, supplements, and herbal products.

How to Take Sustiva

• Standard dosing: 600 mg (one 600 mg tablet) taken once daily, preferably at bedtime to mitigate vivid dreams.
• Reduced dosing: 200 mg (one 200 mg tablet) may be prescribed for patients who require dose reduction due to side effects, drug interactions, or specific pediatric considerations.
• Administration: Swallow the tablet whole with a glass of water. The pill may be taken with or without food.
• Missed dose: If a dose is missed and the next scheduled dose is more than 12 hours away, take the missed tablet as soon as remembered. Do not double the dose.
• Overdose: Symptoms may include severe dizziness, seizures, or profound CNS depression. Seek emergency medical attention; supportive care is the mainstay of treatment.
• Discontinuation: Efavirenz should not be stopped abruptly without medical guidance, as sudden changes can lead to viral rebound. A clinician may advise a gradual transition to an alternative regimen.

Monitoring and Follow-Up

• Baseline and periodic liver function tests (ALT, AST, bilirubin) to detect hepatotoxicity.
• Mental health assessment at initiation and during therapy, especially for patients with a history of depression or psychiatric illness.
• Viral load and CD4+ count every 3-6 months to evaluate treatment effectiveness.
• Therapeutic drug monitoring is rarely required but may be considered in cases of suspected drug-drug interactions or unexpected side effects.

Storage and Handling

• Store Sustiva tablets at room temperature (20-25 °C), protected from excess moisture and direct sunlight.
• Keep the container tightly closed and out of reach of children.
• Do not use the medication after the expiration date printed on the package.

Medication-Specific Glossary

Non-nucleoside reverse transcriptase inhibitor (NNRTI)

A class of antiretroviral drugs that bind directly to reverse transcriptase, preventing HIV-1 from converting its RNA into DNA.

Hepatotoxicity

Liver injury caused by a medication, manifested by elevated liver enzymes or clinical hepatitis.

CNS (Central Nervous System)

The part of the nervous system consisting of the brain and spinal cord; efavirenz commonly affects this system.

Therapeutic drug monitoring (TDM)

Measurement of drug concentrations in blood to maintain a therapeutic level while avoiding toxicity.

Medical Disclaimer

This article provides educational information about Sustiva and is not a substitute for professional medical advice. Treatment decisions, including use for unapproved indications, must be made under the guidance of a qualified healthcare provider. The content is intended for informational purposes and does not constitute medical recommendations. Always consult a physician before starting, stopping, or changing any medication regimen.