Generic Efavirenz

Introduction

Efavirenz is an antiretroviral medication used primarily in the treatment of Human Immunodeficiency Virus (HIV) infection. It belongs to the non‑nucleoside reverse transcriptase inhibitor (NNRTI) class and is widely prescribed in the United Kingdom as part of combination therapy for adults living with HIV. The active compound is Efavirenz; the drug is listed under the anti‑viral, HIV medication group. While its principal indication is HIV‑1 infection, Efavirenz is occasionally studied for other viral conditions, although these uses remain investigational.

What is Efavirenz?

Efavirenz is the generic version of the original brand Sustiva (also marketed as Stocrin in some regions), containing the same active compound, Efavirenz. It is manufactured by several licensed pharmaceutical companies worldwide and supplied in the UK by reputable distributors. Our online pharmacy provides this generic alternative as a cost‑effective treatment option, offering the identical therapeutic molecule at a lower price than the branded product.

How Efavirenz Works

Efavirenz inhibits the HIV‑1 reverse transcriptase enzyme by binding to a hydrophobic pocket adjacent to the enzyme’s active site. This non‑competitive inhibition prevents the conversion of viral RNA into DNA, a critical step required for viral replication within host CD4⁺ T‑cells. By halting the synthesis of proviral DNA, Efavirenz reduces the viral load in the bloodstream, allowing immune recovery when combined with other antiretrovirals. The drug reaches steady‑state plasma concentrations within 5–7 days of daily dosing, and its elimination half‑life averages 40–55 hours, supporting once‑daily administration.

Conditions Treated withavirenz

• HIV‑1 infection (adult) – first‑line combination therapy
  Efavirenz is approved in the UK for use in combination with two nucleoside reverse transcriptase inhibitors (NRTIs) such as tenofovir/emtricitabine or abacavir/lamivudine. Clinical trials (e.g., ACTG 5142, FIRST) demonstrated superior virological suppression compared with some protease‑inhibitor regimens.

• HIV‑1 infection – second‑line or switch strategy
  For patients who experience toxicity or resistance to other NNRTIs, Efavirenz remains a viable switch option when resistance testing confirms susceptibility.

• Pregnancy (selected cases)
  Efavirenz is generally avoided in the first trimester due to teratogenic risk (Category D). In later pregnancy, specialist guidance may allow continued use if benefits outweigh risks.

The drug’s efficacy is reflected in the UK’s public health data, where combination regimens containing Efavirenz have contributed to a sustained decline in HIV‑related morbidity and mortality.

Suitable Candidates for Efavirenz Treatment

Efavirenz is most appropriate for adult patients who:

• Have confirmed HIV‑1 infection and are antiretroviral‑naïve or require a regimen switch.
• Possess no contraindications such as severe hepatic impairment, known hypersensitivity to NNRTIs, or a history of central nervous system (CNS) toxicity.
• Are not pregnant, or are in the second/third trimester after a thorough risk–benefit assessment.
• Can adhere to a once‑daily dosing schedule and tolerate potential CNS effects (e.g., vivid dreams, dizziness).

Patients for whom Efavirenz may be unsuitable include:

• Individuals with known resistance mutations at positions K103N, Y181C, or G190A in the reverse transcriptase gene.
• Those with active psychiatric disorders that could be exacerbated by Efavirenz’s CNS side‑effect profile.
• Pregnant women in the first trimester unless no alternative regimen is viable.

Risks, Side Effects, and Interactions

Common

• Central nervous system: dizziness, vivid dreams, insomnia, somnolence, anxiety.
• Gastro‑intestinal: nausea, vomiting, abdominal pain, diarrhoea.
• Skin: rash, pruritus.
• Metabolic: mild elevation of liver enzymes (ALT/AST).

Rare

• Neuropsychiatric: depression, suicidal ideation, psychosis.
• Cutaneous: severe exfoliative dermatitis, Stevens‑Johnson syndrome.
• Hepatic: clinically significant hepatitis, jaundice.

Serious

• Fatal or life‑threatening reactions: hypersensitivity syndrome, severe hepatic failure, opportunistic infections due to immune reconstitution inflammatory syndrome (IRIS).
• Virologic failure caused by the development of resistance mutations when adherence is suboptimal.

Clinically Relevant Drug–Drug Interactions

• Cytochrome P450 inducers (e.g., rifampicin, carbamazepine, St. John’s wort) markedly reduce Efavirenz plasma levels, risking therapeutic failure.
• CYP2B6 polymorphisms can increase exposure, heightening CNS toxicity; dose adjustment may be required in poor metabolizers.
• Coadministration with warfarin may potentiate anticoagulant effect; INR monitoring is advised.
• Anticonvulsants (e.g., phenytoin, phenobarbital) can lower Efavirenz concentrations.
• Hormonal contraceptives may have reduced efficacy; barrier methods or alternative contraception should be considered.

Patients should disclose all current medications, including over‑the‑counter and herbal products, to their healthcare provider.

Practical Use: Dosing, Missed Dose, Overdose

• Standard dose: 600 mg (one tablet) taken orally once daily, preferably at bedtime to minimise CNS effects.
• Food: Efavirenz can be taken with or without food; a fatty meal slightly increases absorption but is not required.
• Missed dose: If a dose is missed and it is less than 12 hours until the next scheduled dose, skip the missed tablet and continue with the regular schedule. Do not double‑dose.
• Overdose: Symptoms may include severe CNS depression, seizures, or respiratory compromise. Immediate medical attention is required; supportive care is the mainstay of treatment.
• Renal impairment: No dose adjustment needed as Efavirenz is primarily hepatically metabolised.
• Hepatic impairment: Use caution in moderate to severe liver disease; dose reduction to 400 mg daily may be considered under specialist supervision.

Buying Efavirenz from Our Online Pharmacy

Efavirenz can be purchased from our online pharmacy in the UK with a focus on safety, affordability, and privacy.

• Competitive pricing – The generic formulation is offered at near‑manufacturer cost, substantially lower than branded alternatives.
• Verified quality – All stock is sourced from licensed overseas suppliers who meet European Medicines Agency (EMA) Good Manufacturing Practice (GMP) standards.
• Discreet delivery – Packages are sealed in unbranded envelopes and dispatched via secure courier services (express delivery within 7 days or regular airmail in approximately 3 weeks).
• International access – As a pharmacy broker service, we partner with reputable overseas pharmacies, enabling patients who have limited access through NHS formularies or private insurers to obtain this essential medication.

Our service respects patient confidentiality and complies with UK import regulations for personal use of prescription medicines.

FAQ

• Is Efavirenz available in both brand‑name and generic forms in the UK?
  Yes. The original brand‑name product is marketed as Sustiva, while generic Efavirenz contains the identical active compound and is typically more affordable.

• What should I do if I travel abroad with Efavirenz?
  Keep the medication in its original packaging, carry a copy of the prescription or a doctor’s note, and store it at room temperature away from direct heat or moisture.

• Does Efavirenz require any special storage conditions?
  The tablets should be stored at 15‑30 °C, protected from light and humidity. Do not refrigerate or freeze.

• Are there differences in tablet appearance between regions?
  In the UK, generic Efavirenz tablets are usually white, round, film‑coated, and bear the dosage strength on one side. Brand‑name Sustiva tablets may have distinct imprint codes.

• Can Efavirenz be imported for personal use under UK law?
  Personal import of a single‑course supply for a private individual is permissible, provided the medication is for personal use, accompanied by a valid prescription, and the total quantity does not exceed a three‑month supply.

• Do any ethnic groups have specific warnings for Efavirenz?
  Individuals of Asian ancestry often have a higher prevalence of the CYP2B6*6 allele, which can increase Efavirenz plasma concentrations and raise the risk of CNS side effects. Dose adjustments may be required.

• What are the most common CNS side effects, and how long do they last?
  Vivid dreams, insomnia, and dizziness are reported by up to 30 % of users, usually emerging within the first two weeks of therapy. Many patients experience attenuation of symptoms after 4–6 weeks.

• How does Efavirenz compare with other NNRTIs such as rilpivirine?
  Efavirenz has a longer half‑life and is more tolerant of occasional missed doses, whereas rilpivirine requires strict adherence to fasting conditions and may have fewer CNS effects but a lower barrier to resistance.

• Is there any impact of Efavirenz on hormonal contraceptive efficacy?
  Efavirenz can reduce plasma concentrations of estrogen‑containing contraceptives, potentially decreasing their effectiveness. Non‑hormonal or barrier methods should be used concurrently.

• What inactive ingredients are present in the generic tablets?
  Common excipients include lactose, magnesium stearate, microcrystalline cellulose, and hydroxypropyl methylcellulose. Patients with specific allergies should review the full ingredient list.

Glossary

Non‑nucleoside reverse transcriptase inhibitor (NNRTI)

A class of antiretroviral drugs that bind to reverse transcriptase at a site distinct from the nucleoside binding pocket, preventing viral DNA synthesis without incorporation into the viral chain.

CYP2B6 polymorphism

Genetic variations in the cytochrome P450 2B6 enzyme that affect how quickly a person metabolises Efavirenz, influencing drug levels and risk of side effects.

Therapeutic drug monitoring (TDM)

The measurement of specific drug concentrations in blood at designated intervals to maintain a constant plasma level within a target range, often used for drugs with narrow therapeutic windows.

Stevens‑Johnson syndrome (SJS)

A rare, severe skin reaction characterized by widespread epidermal necrosis and detachment, considered a medical emergency requiring immediate drug discontinuation.

⚠️ Disclaimer

The information provided about Efavirenz is for general knowledge only. It does not replace professional medical consultation. All treatment decisions should be made under the supervision of a qualified healthcare provider. We assume all readers are responsible adults capable of making informed decisions about their health. Our online pharmacy offers access to Efavirenz for individuals who may have limited availability through traditional pharmacies, prescription‑based insurance schemes, or who are seeking affordable generic alternatives. Always consult your doctor before starting, changing, or discontinuing any medication.