Viramune (Nevirapine)

What Is Viramune and What Is It Used For?

Viramune belongs to a class of antiretroviral medications known as non-nucleoside reverse transcriptase inhibitors (NNRTIs). These medications are a cornerstone of combination antiretroviral therapy (cART), which is the standard of care for managing HIV-1 infection worldwide. The active substance, nevirapine, was first approved by the U.S. Food and Drug Administration (FDA) in 1996 and remains on the World Health Organization (WHO) Model List of Essential Medicines.

How Nevirapine Works

HIV-1 relies on an enzyme called reverse transcriptase to convert its RNA genetic material into DNA, a critical step in the viral replication cycle. Nevirapine binds directly to the reverse transcriptase enzyme at a site distinct from where nucleoside analogues bind, causing a conformational change that disrupts the enzyme's ability to function. By blocking this essential step, nevirapine prevents the virus from multiplying and infecting new cells.

Unlike nucleoside reverse transcriptase inhibitors (NRTIs), which must be activated (phosphorylated) inside cells before they can work, nevirapine acts directly without requiring metabolic activation. This makes it part of the "non-nucleoside" category of reverse transcriptase inhibitors. However, because HIV can develop resistance to NNRTIs relatively quickly, nevirapine must always be used in combination with at least two other antiretroviral drugs.

Approved Indications

Viramune is indicated for the treatment of HIV-1 infection in combination with other antiretroviral agents. It is approved for use in:

• Adults and adolescents as part of a combination antiretroviral regimen
• Children aged 3 years and older who can swallow tablets (oral suspension is available for younger children or those unable to swallow tablets)

The extended-release (XR) formulation of Viramune, available as a 400 mg tablet, is designed to be taken once daily after the initial lead-in period. This offers improved convenience compared to the twice-daily immediate-release formulation and may help improve treatment adherence. The extended-release tablet should only be initiated after a successful 14-day lead-in period with the 200 mg immediate-release formulation, unless the patient is already on a stable nevirapine regimen and is being switched to the extended-release form.

According to international HIV treatment guidelines from the WHO, DHHS (U.S. Department of Health and Human Services), and BHIVA (British HIV Association), nevirapine-based regimens remain an option particularly in resource-limited settings and for patients who cannot tolerate integrase inhibitor-based or other preferred first-line regimens.

What Should You Know Before Taking Viramune?

Before starting Viramune, your prescribing physician will carefully evaluate your medical history, current medications, and liver function. Because nevirapine carries risks of serious and potentially fatal adverse reactions, understanding the contraindications, warnings, and precautions is critically important for safe treatment.

Contraindications

You should not take Viramune if any of the following apply:

• You are allergic to nevirapine or any other ingredient in the formulation (inactive ingredients include lactose monohydrate, hypromellose, yellow iron oxide, and magnesium stearate)
• You have previously stopped nevirapine due to severe skin rash, rash accompanied by systemic symptoms (fever, blistering, oral lesions, eye inflammation, facial swelling, muscle or joint pain, general malaise, shortness of breath, or abdominal pain), hypersensitivity reactions, or hepatitis
• You have severe hepatic impairment (Child-Pugh class B or C)
• You are taking products containing St. John's Wort (Hypericum perforatum), as this herbal remedy can significantly reduce nevirapine blood levels and lead to treatment failure

Warnings and Precautions

During the first 18 weeks of treatment, you and your healthcare provider must be vigilant for signs of liver or skin reactions. These are the most clinically significant risks associated with nevirapine therapy.

Hepatotoxicity risk factors: The following patients have an increased risk of developing liver problems with nevirapine:

• Women — particularly those with CD4+ cell counts above 250 cells/mm³ at the start of treatment
• Men with CD4+ cell counts above 400 cells/mm³ at initiation
• Patients co-infected with hepatitis B or hepatitis C
• Patients with elevated baseline liver enzymes
• Previously treatment-naive patients with detectable HIV-1 viral load and high CD4+ counts

Skin reactions: Rash is the most common adverse event with nevirapine. While most rashes are mild to moderate, some patients develop severe or life-threatening skin reactions including Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). If you experience any rash accompanied by fever, blistering, oral sores, eye inflammation, facial swelling, or general malaise, you must stop taking Viramune immediately and contact your doctor.

Immune Reconstitution Inflammatory Syndrome (IRIS): In patients with advanced HIV infection who begin antiretroviral therapy, the recovering immune system may trigger an inflammatory response to previously acquired opportunistic infections. Symptoms of these pre-existing infections may emerge or worsen shortly after starting treatment. Additionally, autoimmune conditions (such as Graves' disease, polymyositis, or Guillain-Barré syndrome) may occur months after treatment initiation. Report any new symptoms to your doctor promptly.

Body fat redistribution: Patients receiving combination antiretroviral therapy may experience changes in body fat distribution (lipodystrophy), including increased fat in the abdomen, breasts, and back of the neck, along with loss of fat from the face, limbs, and buttocks. The long-term health consequences of these changes are not fully understood.

Osteonecrosis: Cases of bone death (osteonecrosis) have been reported in patients on combination antiretroviral therapy. Risk factors include prolonged therapy duration, corticosteroid use, alcohol consumption, immunosuppression, and higher body mass index. Symptoms include joint stiffness and pain, particularly in the hips, knees, and shoulders.

Pregnancy and Breastfeeding

If you are pregnant, think you may be pregnant, or are planning a pregnancy, consult your healthcare provider before taking Viramune. The decision to use nevirapine during pregnancy must weigh the benefits of HIV treatment against the potential risks, particularly the increased risk of hepatotoxicity in women with higher CD4+ counts.

Breastfeeding is not recommended for women living with HIV because the virus can be transmitted to the infant through breast milk. If you are breastfeeding or considering doing so, discuss this with your doctor as soon as possible.

Driving and Operating Machinery

Viramune may cause fatigue as a side effect. If you experience tiredness or exhaustion while taking this medication, exercise caution when driving or operating machinery. Avoid potentially hazardous activities until you know how the medication affects you.

Lactose Content

Viramune extended-release tablets contain lactose (as monohydrate). Patients with rare hereditary galactose intolerance, Lapp lactase deficiency, or glucose-galactose malabsorption should consult their doctor before taking this medicine.

How Does Viramune Interact with Other Drugs?

Nevirapine is metabolized by the cytochrome P450 enzyme system, primarily CYP3A4 and CYP2B6, and is also an inducer of these enzymes. This means nevirapine can accelerate the breakdown of other drugs that are processed by the same pathways, potentially reducing their effectiveness. Conversely, some medications can alter nevirapine levels, either increasing the risk of toxicity or decreasing its antiviral efficacy.

It is essential to tell your doctor or pharmacist about all medications you are taking, including prescription drugs, over-the-counter medicines, vitamins, and herbal supplements, before starting Viramune. Your doctor may need to adjust doses or substitute alternative medications.

Major Interactions

Antiretroviral Interactions

Other Notable Interactions

• Fluconazole: May increase nevirapine exposure; monitor for nevirapine toxicity
• Itraconazole: Nevirapine may significantly reduce itraconazole levels
• Rifabutin: Preferred over rifampicin for TB co-treatment; monitor for efficacy
• Clarithromycin: Reduced clarithromycin levels; consider alternative macrolide
• Hormone replacement therapy: Effectiveness may be reduced; discuss alternatives with your doctor
• Prednisone: Should not be used to treat nevirapine-associated rash, as it has not been shown to be beneficial and may increase the risk of rash progression

What Is the Correct Dosage of Viramune?

Viramune must always be taken according to your doctor's instructions and in combination with at least two other antiretroviral medications. The dosing regimen includes a mandatory lead-in period designed to reduce the risk of skin reactions. Never exceed the prescribed dose or alter the dosing schedule without consulting your healthcare provider.

Adults

Children and Adolescents

Viramune 400 mg extended-release tablets may be used in children who meet all of the following criteria:

• Age 8 years or older and weighing at least 43.8 kg, or
• Age 3 to under 8 years and weighing at least 25 kg, or
• Body surface area (BSA) of 1.17 m² or greater

For younger or smaller children, an oral suspension formulation is available with weight-based dosing. All pediatric patients must also complete the 14-day lead-in period with the appropriate immediate-release formulation before transitioning to extended-release tablets.

Renal or Hepatic Impairment

Patients with mild hepatic impairment (Child-Pugh A) may use nevirapine with caution and enhanced liver monitoring. Viramune extended-release tablets should not be used in patients with moderate or severe hepatic impairment; only the 200 mg immediate-release tablet or 50 mg/5 ml oral suspension should be used in these patients. For patients undergoing dialysis, an additional 200 mg dose after each dialysis session is recommended, as nevirapine is partially cleared by hemodialysis.

Missed Dose

Adherence to your prescribed antiretroviral regimen is essential for maintaining viral suppression and preventing the development of drug resistance. If you miss a dose:

• Within 12 hours: Take the missed dose as soon as possible, then continue your normal schedule.
• More than 12 hours late: Skip the missed dose entirely and take the next dose at the regular scheduled time. Do not double your dose.

Overdose

There is limited clinical data on nevirapine overdose. Reported cases have included doses of 800 mg to 6,000 mg, with symptoms such as edema, erythema nodosum, fatigue, fever, headache, insomnia, nausea, pulmonary infiltrates, rash, vertigo, vomiting, and weight decrease. There is no specific antidote for nevirapine overdose. If an overdose is suspected, contact your doctor or emergency services immediately. Treatment is supportive, and standard medical interventions (including monitoring of vital signs and clinical observation) should be employed.

What Are the Side Effects of Viramune?

Like all medications, Viramune can cause side effects, though not everyone experiences them. During HIV treatment, weight gain and increased levels of blood lipids and glucose may occur. These changes are partly related to restored health and lifestyle factors, though some may be linked to the antiretroviral medications themselves. Your doctor will regularly monitor for such metabolic changes.

The side effects below are organized by frequency, as observed during clinical trials and post-marketing surveillance. Understanding these frequencies can help you and your doctor make informed decisions about your treatment.

During the 14-Day Lead-In Period (200 mg IR tablets)

During Extended-Release Maintenance Therapy (400 mg XR tablets)

Additional Side Effects with Combination Therapy

When Viramune has been used in combination with other antiretroviral medications, the following side effects have also been reported. These are common with other HIV drugs and are not necessarily caused by nevirapine specifically:

• Decreased red blood cell or platelet counts
• Pancreatitis (inflammation of the pancreas)
• Peripheral neuropathy (decreased or abnormal skin sensation, tingling, numbness)

Side Effects in Children

In pediatric patients, granulocytopenia (reduced white blood cells) occurs more frequently than in adults. Anemia (reduced red blood cells), which may be related to nevirapine treatment, has also been observed more often in children. As with adults, any rash in a child should be promptly reported to the treating physician.

How Should You Store Viramune?

Proper storage of medications is essential to ensure they remain effective and safe throughout their shelf life. Viramune does not require any special storage conditions, but the following guidelines should be observed:

• Keep out of sight and reach of children at all times
• Store at room temperature — no special temperature requirements
• Use within 2 months after first opening the container
• Do not use after the expiry date (marked "EXP" on the carton and blister pack). The expiry date refers to the last day of the stated month
• Do not dispose of medications via wastewater or household waste. Ask your pharmacist about proper medication disposal procedures to help protect the environment

If you notice any change in the appearance of your tablets (discoloration, unusual odor, or damage), do not take them and consult your pharmacist. Always check the packaging for signs of tampering before use.

What Does Viramune Contain?

Active Ingredient

Each extended-release tablet contains 400 mg of nevirapine. Nevirapine is the pharmacologically active component responsible for the antiviral activity against HIV-1.

Inactive Ingredients (Excipients)

• Lactose monohydrate — a filler/diluent derived from milk sugar
• Hypromellose (HPMC) — a polymer that creates the extended-release matrix, allowing gradual drug release over time
• Yellow iron oxide (E172) — a coloring agent giving the tablet its characteristic yellow appearance
• Magnesium stearate — a lubricant used in tablet manufacturing

Physical Description

Viramune 400 mg extended-release tablets are yellow, oval, and biconvex, measuring approximately 9.3 mm × 19.1 mm. They are debossed with "V04" on one side and the manufacturer's logo on the other. The tablets are available in blister packs of 30 or 90 tablets per carton, or alternatively as 30 tablets in a bottle. Not all pack sizes may be marketed in every country.

Viramune is also available as 200 mg immediate-release tablets and as a 50 mg/5 ml oral suspension for patients who require alternative dosage forms. The manufacturer is Boehringer Ingelheim Pharma GmbH & Co. KG, based in Ingelheim am Rhein, Germany.