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Viramune: Nevirapine 200 mg Pill - UK Overview

Viramune contains the active ingredient nevirapine, a non-nucleoside reverse transcriptase inhibitor (NNRTI) used in combination therapy for HIV-1 infection. It is supplied as a 200 mg film-coated tablet and is classified as a prescription-only medicine (POM) in the United Kingdom. The MHRA regulates its marketing and safety.

How Nevirapine Works in the Body

• Nevirapine binds directly to the reverse transcriptase enzyme of HIV-1, causing a conformational change that blocks the enzyme’s ability to copy viral RNA into DNA.
• This inhibition prevents the integration of viral genetic material into host cells, thereby reducing viral replication.
• The drug is absorbed rapidly after oral administration; peak plasma concentrations are reached in 4-5 hours.
• It is metabolised primarily by hepatic cytochrome P450 3A4 (CYP3A4) and 2B6 enzymes, with a half-life of approximately 45 hours in adults after steady-state is achieved.

Conditions Treated with Viramune

• HIV-1 infection in adults and adolescents: Viramune is approved as part of a combination antiretroviral regimen for treatment-naïve patients and for those switching from other NNRTIs when the overall regimen remains effective.
• Pediatric use (≥2 years of age, weight ≥ 35 kg): The same 200 mg tablet is used under weight-based dosing protocols, as recommended by the British HIV Association (BHIVA).

Patient Suitability and Contraindications

Absolute contraindications

• Known hypersensitivity to nevirapine or any of the tablet excipients.
• Active severe hepatic disease or baseline alanine transaminase (ALT) > 5 × upper limit of normal.

Relative contraindications

• Pregnancy in women with CD4⁺ > 250 cells/µL (increased risk of hepatotoxicity).
• Co-administration with potent CYP3A4 inducers (e.g., rifampicin, carbamazepine, St John’s wort) that may lower nevirapine exposure.
• Existing moderate hepatic impairment; dose adjustment and close monitoring are required.

Special populations

• Pregnancy & lactation: Use is permitted when the benefit outweighs the risk; close liver-function monitoring is advised.
• Elderly: No dosage reduction is required solely for age, but hepatic function should be evaluated.

Safety Profile: Side Effects and Interactions

Common Side Effects

• Rash - often appears within the first two weeks; usually mild and self-limiting.
• Nausea or abdominal discomfort - may lessen when the tablet is taken with food.
• Headache, fatigue, insomnia - reported in up to 10 % of patients.

Serious Adverse Events

• Hepatotoxicity - jaundice, elevated transaminases, or fulminant liver failure; monitor liver tests regularly, especially during the first 8 weeks.
• Severe skin reactions - Stevens-Johnson syndrome or toxic epidermal necrolysis; immediate medical attention is required if a rash progresses or is accompanied by fever.

Drug Interactions

• Major CYP3A4 inducers (rifampicin, carbamazepine, phenytoin, St John’s wort): reduce nevirapine plasma levels → risk of virologic failure.
• CYP3A4 inhibitors (ketoconazole, itraconazole, protease inhibitors such as lopinavir/ritonavir): increase nevirapine concentrations → heightened liver-toxic risk.
• Oral contraceptives: nevirapine may lower steroid levels; supplemental contraception should be considered.

Food and Lifestyle Interactions

• The tablet can be taken with or without food; taking it with meals may lessen gastrointestinal upset.
• Alcohol does not have a direct pharmacokinetic interaction but excessive intake can compound liver stress.
• No known impairment of driving or use of machinery; however, severe rash or dizziness should prompt caution.

Dosing and Administration Guidelines

• Standard adult regimen

• Day 1-14: 200 mg (one tablet) once daily.

• Day 15 onward: 200 mg twice daily (morning and evening).

• Pediatric dosing (≥ 35 kg) follows the same adult schedule; lighter children receive weight-adjusted doses as per BHIVA guidance.

• Administration tips

• Swallow the tablet whole; do not crush or chew.

• Take with a glass of water; food may be taken concurrently to improve tolerance.

• If a dose is missed and the next scheduled dose is more than 8 hours away, take the missed dose; otherwise skip it and continue the regular schedule. Do not double-dose.

• Overdose

• Symptoms may include severe nausea, vomiting, dizziness, and hepatic dysfunction.

• Seek emergency care; supportive measures and monitoring of liver function are the primary interventions.

• Discontinuation

• Stopping nevirapine abruptly can lead to viral rebound; tapering is not required, but any change should be overseen by a clinician.

Monitoring and Follow-Up

• Baseline: Liver function tests (ALT, AST, bilirubin) and CD4⁺ cell count.
• First 8 weeks: Repeat liver enzymes every 2 weeks; increase monitoring frequency if abnormalities emerge.
• Beyond 8 weeks: Monthly liver tests until stable, then every 3-6 months as part of routine HIV care.
• Clinical assessment: Prompt evaluation of any new rash or flu-like symptoms.

Storage and Handling

• Store at room temperature (15-30 °C), protected from moisture and direct sunlight.
• Keep the bottle tightly closed and out of reach of children.
• Do not use tablets after the printed expiry date; dispose of unused medication according to local pharmacy take-back programs.

Medication-Specific Glossary

Reverse Transcriptase Inhibitor

A class of antiretroviral drugs that block the enzyme HIV uses to convert its RNA into DNA, a crucial step in viral replication.

CYP3A4

A liver enzyme responsible for metabolising many drugs, including nevirapine; its activity can be increased or decreased by other substances, altering drug levels.

Stevens-Johnson Syndrome

A rare, severe skin reaction characterized by widespread blistering and detachment of the epidermis; requires immediate medical care.

Medical Disclaimer

This article provides educational information about Viramune (nevirapine) 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.