Clovir400 mg

Genital Herpes (Oral Clovir)

Clovir is an FDA-approved, guideline-supported (CDC) treatment for genital herpes caused by herpes simplex virus. It is indicated for:

• Initial episode: treatment of the first clinical episode of genital herpes — established indication.
• Recurrent (episodic) episodes: management of recurrent outbreaks when Clovir is started early, in the prodrome or at first sign of lesions — established indication.
• Chronic suppressive therapy: daily Clovir reduces the frequency of recurrences in patients with frequent outbreaks — established, guideline-supported indication.

Herpes Zoster / Shingles (Oral Clovir)

Clovir is an established, FDA-approved treatment for acute herpes zoster (shingles) in immunocompetent adults, most effective when started within 72 hours of rash onset.

Chickenpox / Varicella (Oral Clovir)

Clovir is FDA-approved for treatment of chickenpox in patients 2 years and older. However, current CDC/AAP guidance does not recommend routine Clovir treatment for otherwise healthy children with typical, uncomplicated chickenpox; oral Clovir is guideline-supported specifically for higher-risk groups — healthy individuals older than 12 years, those with chronic skin or lung disease, patients on long-term salicylate or corticosteroid therapy, and secondary household cases — when Clovir is started within 24 hours of rash onset.

Herpes Labialis / Cold Sores (Topical Clovir Cream)

Clovir cream 5% is FDA-approved for treatment of recurrent herpes labialis (cold sores) on the lips and face in immunocompetent adults and adolescents 12 years and older, applied during the prodrome or as soon as lesions appear. Use of Clovir cream in immunocompromised patients has not been established.

Severe or Disseminated Herpesvirus Infections (IV Clovir)

Intravenous Clovir is an established, guideline-supported treatment for infections that are severe, disseminated, or occurring in patients who cannot tolerate oral therapy, including:

• Mucosal and cutaneous herpes simplex virus infections in immunocompromised patients — established.
• Severe initial episodes of genital herpes, particularly requiring hospitalization — established.
• Herpes simplex encephalitis — established.
• Neonatal herpes simplex virus infection — established, specialist-directed.
• Varicella-zoster (chickenpox/shingles) infection in immunocompromised patients — established.

IV Clovir must be administered by, or under the direction of, a qualified healthcare professional in a hospital setting.

Acyclovir is available in Bangladesh in the following strengths and formulations: oral tablets containing Acyclovir 200 mg or 400 mg; oral suspension containing Acyclovir 200 mg/5 mL; topical cream containing Acyclovir 5% w/w; and Acyclovir sodium powder for IV infusion available in 250 mg, 500 mg, and 1 g vials.

Clovir is an antiviral medicine used to treat infections caused by herpes simplex virus and varicella-zoster virus. Clovir works by slowing the growth and spread of the virus so the body's immune system can help control the infection, though Clovir does not cure or permanently eliminate the virus from the body. Clovir is available as tablets and oral suspension for genital herpes, cold sores, chickenpox, and shingles; as a topical cream for cold sores on the lips; and as an intravenous infusion for severe infections requiring hospital care. Starting Clovir as early as possible after symptoms begin usually gives the best results. Clovir should always be taken exactly as prescribed by a qualified healthcare professional.

Antiviral (Nucleoside Analogue)

Acyclovir is a synthetic purine nucleoside analogue. Inside cells infected with herpes simplex virus (HSV-1, HSV-2) or varicella-zoster virus (VZV), the viral enzyme thymidine kinase converts Acyclovir into Acyclovir monophosphate, which host cell enzymes further convert to Acyclovir triphosphate. This active form competitively inhibits viral DNA polymerase, is incorporated into the growing viral DNA chain causing chain termination, and inactivates the viral DNA polymerase, thereby halting viral replication. Because this activation step depends on a virus-specific enzyme, the antiviral action of Acyclovir is highly selective for virus-infected cells, with much less effect on uninfected host cells. After oral dosing, Acyclovir has variable, dose-dependent bioavailability of roughly 10-20%; food does not significantly affect absorption. Acyclovir is eliminated primarily by the kidneys, with an elimination half-life of approximately 2.5 to 3.3 hours in patients with normal renal function — this is why Acyclovir dosing must be adjusted in renal impairment (see Precautions & Warnings).

• Tablets/suspension: Clovir may be taken with or without food; swallow tablets with a full glass of water; shake the oral suspension well and measure each dose with an accurate oral syringe or measuring cup.
• Maintain adequate hydration while taking oral or IV Clovir, especially at higher doses, to help protect the kidneys (see Precautions & Warnings for the full explanation).
• Topical cream: wash and dry hands before and after applying Clovir cream; apply a thin layer to the affected external lip/face area only — avoid the eyes, inside the mouth, and mucous membranes; do not cover with a bandage unless advised.
• IV infusion: Clovir is administered only by a healthcare professional in a hospital or clinical setting, given as a slow infusion over at least 1 hour — never as a rapid or bolus injection.
• Take or apply Clovir doses at evenly spaced times and complete the full prescribed course even if symptoms improve early.
• Starting Clovir as early as possible after the first sign of symptoms (tingling, prodrome, or lesion) gives the best results for episodic use.

• Probenecid: reduces renal excretion of Clovir, increasing Clovir plasma concentration and half-life, which may raise the risk of Clovir-related side effects.
• Other nephrotoxic drugs (e.g., aminoglycosides, cyclosporine, tacrolimus, NSAIDs): coadministration with Clovir, especially IV or high-dose oral Clovir, may increase the risk of kidney dysfunction.
• Mycophenolate mofetil: Clovir and the active metabolite of mycophenolate mofetil compete for renal tubular excretion, which can raise blood levels of both drugs when combined with Clovir, most relevant in transplant patients.
• Zidovudine: concurrent use with Clovir has been associated with increased drowsiness and lethargy in some patients.
• Theophylline: limited evidence suggests Clovir may affect theophylline levels; monitoring may be advised if combined with Clovir.

Always inform your healthcare professional or pharmacist about all other medicines, including over-the-counter drugs and supplements, before starting Clovir.

Common Side Effects

Clovir can commonly cause nausea, vomiting, diarrhea, headache, and tiredness/malaise with oral or IV use, and mild rash or itching. With Clovir cream, local skin reactions such as dryness, burning, stinging, cracking, or flaking at the application site may occur. With IV Clovir, pain or inflammation at the infusion site is common.

Serious Side Effects — Seek Medical Attention

• Signs of kidney problems — decreased urination, swelling, unusual tiredness (see Precautions & Warnings for full explanation).
• Neurological effects — confusion, agitation, hallucinations, tremors, seizures, or unusual drowsiness, more common in elderly patients or those with renal impairment.
• Signs of thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS) — unusual bruising or bleeding, severe fatigue, pallor — rare, reported mainly in immunocompromised patients receiving IV Clovir.
• Severe allergic reaction — swelling of the face, lips, or throat, difficulty breathing, hives.
• Severe skin reactions — blistering or peeling skin (Stevens-Johnson syndrome, toxic epidermal necrolysis) — rare.
• Signs of liver problems — yellowing of the skin or eyes.

Pregnancy

Clovir crosses the placenta. Clovir has been used in pregnancy for many years, and a prospective pregnancy registry following 749 pregnancies with first-trimester exposure to Clovir found a rate of birth defects similar to that in the general population; however, the registry was not large enough to rule out risk for less common defects, and no formal, adequately controlled human studies of Clovir exist. Clovir should be used during pregnancy only if the potential benefit to the mother justifies the potential risk to the fetus, and only under the direction of a qualified healthcare professional — this applies to oral, topical, and IV Clovir alike.

Breastfeeding

Clovir passes into breast milk, at concentrations reported to range from about 0.6 to 4.1 times the corresponding maternal plasma level. A breastfed infant could be exposed to a small amount of Clovir through milk. Clovir should be given to a breastfeeding mother with caution and only when clearly indicated by a healthcare professional; Clovir cream applied to skin away from the breast, so it cannot transfer to the infant during feeding, carries minimal systemic absorption.

• Kidney function and hydration (important): Clovir is eliminated from the body mainly by the kidneys, and can crystallize in kidney tubules when its solubility limit is exceeded, particularly with IV Clovir, high oral doses, or dehydration. This can cause acute kidney injury or, rarely, kidney failure, which has been fatal in some reported cases. To reduce this risk: maintain adequate fluid intake throughout treatment with Clovir, especially with IV therapy or high-dose oral regimens; IV Clovir must be infused slowly over at least 1 hour, never given as a rapid or bolus injection; and the dose of Clovir must be reduced in patients with reduced kidney function or in older adults, who often have lower kidney function than younger patients even with normal-appearing lab results. Report any decrease in urination, swelling, or unusual tiredness to a healthcare professional promptly.
• Neurological effects: confusion, agitation, hallucinations, tremors, drowsiness, or seizures have been reported with Clovir, more often in elderly patients or those with underlying kidney impairment; use caution and seek medical advice if these occur.
• Immunocompromised patients: rare but serious blood disorders (TTP/HUS) have been reported with IV Clovir in immunocompromised patients; these require prompt medical evaluation.
• Topical Clovir cream — for external use only: avoid contact with the eyes, inside the mouth, nose, or genital mucous membranes; effectiveness and safety of Clovir cream have not been established in immunocompromised patients.
• Not a cure: Clovir does not eliminate the herpes virus from the body and does not prevent transmission to others; appropriate precautions should still be followed during active lesions.
• Elderly patients: may be more susceptible to the kidney and neurological side effects of Clovir; dose adjustment based on kidney function is often needed (see Use in Special Populations).

Reported symptoms of Clovir overdose include agitation, confusion, drowsiness/lethargy, and seizures. Excess Clovir can crystallize in the kidney tubules, which may lead to acute kidney injury. If an overdose of Clovir is suspected, do not induce vomiting unless specifically directed to do so by a healthcare professional or poison control service, and seek emergency medical attention or contact a poison control center immediately. Maintaining adequate hydration is important, and hemodialysis may be used by treating physicians to help remove Clovir from the blood in cases of significant overdose with kidney impairment.

Store according to the product label. In general, keep Clovir tablets, suspension, and cream below 25°C, protected from light and moisture, and out of the reach of children. IV Clovir is prepared and stored according to hospital pharmacy protocols; once reconstituted or diluted, Clovir should be used within the timeframe specified on the product label (see Reconstitution).

Children

The safety and effectiveness of oral Clovir tablets/suspension in children younger than 2 years have not been established for most indications. Clovir cream is approved only for immunocompetent patients 12 years and older with recurrent cold sores. IV Clovir is used in infants and children, including neonates, for serious infections such as neonatal herpes and encephalitis, with doses calculated by body weight and administered only under specialist hospital care. For chickenpox, routine Clovir treatment is not recommended for otherwise healthy children; oral Clovir is generally reserved for children older than 12 years or those with specific risk factors, as determined by a healthcare professional.

Elderly

Older adults may have reduced kidney function even when standard lab tests appear normal, and are more likely to experience neurological side effects from Clovir and require dose adjustment. See the renal/hydration precaution above.

Renal Impairment

Because Clovir is cleared mainly by the kidneys, patients with reduced kidney function require dose and/or interval adjustment for both oral and IV Clovir, as outlined in the Dosage table. Adequate hydration is essential (see Precautions & Warnings).

Hepatic Impairment

Specific dose adjustment data for Clovir in hepatic impairment are limited; Clovir should be used with caution in patients with significant liver disease, under the guidance of a healthcare professional.

Immunocompromised Patients

Higher doses and IV formulations of Clovir are often used for immunocompromised patients (e.g., transplant recipients, HIV-positive individuals) with herpes or varicella-zoster infections, and these patients should be monitored closely for renal and hematologic effects.

Duration of Clovir therapy depends on the indication: genital herpes (initial episode) 7-10 days; genital herpes (recurrent episodic therapy) 2-5 days depending on the regimen; genital herpes suppressive therapy up to 12 months before re-evaluation; herpes zoster (shingles) 7-10 days; chickenpox 5 days; herpes labialis (topical Clovir cream) 4 days; and IV Clovir for severe infections 5-21 days depending on the specific condition (see Dosage table). The prescribing healthcare professional determines the exact duration of Clovir treatment for each patient.

Clovir sodium for IV infusion is supplied as a powder in vials and must be reconstituted and further diluted by a qualified healthcare professional before use — for example, a 500 mg vial of Clovir is reconstituted with Sterile Water for Injection to a concentration of approximately 50 mg/mL, then further diluted in an IV fluid to a concentration of 7 mg/mL or less before slow infusion over at least 1 hour. Reconstituted/diluted Clovir solution should be used within the timeframe specified by the manufacturer and never given as a rapid or bolus injection. This process must only be performed by trained healthcare personnel.

Antiviral; Synthetic Purine Nucleoside Analogue; Herpesvirus DNA Polymerase Inhibitor

Acyclovir is converted inside virus-infected cells, first by viral thymidine kinase and then by host cell enzymes, into Acyclovir triphosphate. This active form of Acyclovir inhibits viral DNA polymerase, is incorporated into viral DNA to cause chain termination, and inactivates the viral DNA polymerase — together halting replication of herpes simplex virus and varicella-zoster virus DNA.

Clovir is used in children for several herpesvirus infections, with the formulation, dose, and indication depending on age and condition:

• Chickenpox (varicella): oral Clovir is not routinely recommended for healthy children with typical chickenpox; when indicated for higher-risk children (e.g., age over 12 years, chronic skin/lung disease, salicylate or corticosteroid therapy), Clovir dosing in children 2 years and older is generally 20 mg/kg per dose (up to a maximum of 800 mg per dose) four times daily for 5 days, started within 24 hours of rash onset.
• Severe HSV or varicella-zoster infections, including neonatal herpes and encephalitis: treated with weight-based IV Clovir in a hospital setting under specialist supervision (see Dosage table).
• Oral Clovir tablets/suspension for herpes simplex infections other than chickenpox: safety and effectiveness in children under 2 years have not been established.
• Clovir cream: approved only for immunocompetent adolescents 12 years and older with recurrent cold sores.

Any use of Clovir in a child should be directed and monitored by a pediatrician or qualified healthcare professional.