Aciclovir is a medication with the active ingredient acyclovir. It is also known by other names such as Zovirax and Acyclovir. It is used to treat viral infections like herpes simplex, chickenpox, and shingles.
You can expect to pay between £0.34 and £1.5 for Aciclovir per pills. Prices vary with the packaging size and active ingredient quantity (30 or 360 mg).
Aciclovir is an antiviral medication. It belongs to the class of drugs known as nucleoside analogs. Its primary mechanism involves inhibiting viral DNA polymerase. It is used predominantly in the treatment of herpes simplex and varicella-zoster viruses.
Aciclovir gets converted into aciclovir triphosphate inside infected cells. This inhibits viral DNA synthesis by acting as a competitive substrate for viral DNA polymerase. The drug’s incorporation causes chain termination of viral DNA. The selectivity towards infected cells minimizes effect on uninfected cells.
Aciclovir is indicated for the treatment of herpes simplex encephalitis. It is also prescribed for initial and recurrent episodes of genital herpes. Patients with varicella (chickenpox) and herpes zoster (shingles) benefit from its antiviral properties. It is used off-label for prophylaxis in immunocompromised patients.
Adult dosage for genital herpes include 200 mg five times a day for ten days. For herpes zoster, typical dosing is 800 mg five times a day for seven to ten days. Pediatric dosing for varicella ranges from 20 mg/kg to a maximum of 800 mg four times a day for five days. Renal impairment necessitates dosage adjustments.
Oral bioavailability of Aciclovir is approximately 10-20%. Peak plasma concentrations are achieved within 1.5-2 hours post-dose. Renal excretion is the primary route of elimination, both as unchanged drug and metabolites. Plasma half-life in patients with normal renal function ranges from 2 to 3 hours.
Resistance against Aciclovir may develop in herpes virus strains due to mutations in the thymidine kinase gene. Resistant strains are often observed in patients with AIDS or undergoing long-term therapy. Resistance results in reduced susceptibility to aciclovir, necessitating alternative treatments.
Concomitant use of probenecid with Aciclovir may reduce its renal clearance, leading to increased plasma levels. Coadministration with zidovudine may increase the risk of neurotoxicity. Concurrent use with nephrotoxic drugs can enhance the risk of renal impairment. Interactions with mycophenolate mofetil may increase aciclovir concentration due to competition for renal excretion pathways.
Common adverse reactions include nausea, vomiting, and diarrhea. Neurotoxicity effects such as headache, dizziness, and confusion may occur, particularly in elderly patients. Renal toxicity is reflected in increased serum creatinine levels, especially with intravenous administration. Thrombocytopenia and leukopenia are hematologic side effects observed in a minority of patients.
Renal function should be meticulously monitored, especially in patients with pre-existing renal impairment. Periodic complete blood counts are recommended to detect hematologic abnormalities. Liver function tests should be undertaken to monitor for hepatotoxicity. Neurological assessments are necessary in patients exhibiting signs of neurotoxicity.
In pregnancy, aciclovir should be used only if the potential benefits outweigh risks, as data on fetal harm are inconclusive. Lactating mothers should consult healthcare providers before use, as the drug is excreted in human milk. Pediatric usage requires careful dosing based on weight and age, with close monitoring for adverse effects. Geriatric patients may need dose adjustments due to variable kidney function decline.
Store aciclovir tablets at room temperature, between 20°C and 25°C, in a tightly closed container. Protect from light and moisture to maintain efficacy. Reconstituted intravenous aciclovir should be stored at 2°C to 8°C for no more than 24 hours. Unused portions of reconstituted solutions should be discarded to prevent microbial contamination.
Aciclovir is available in multiple formulations including oral tablets, capsules, and suspensions. Topical formulations exist for direct application on herpes lesions. An intravenous formulation is indicated for severe or systemic infections and requires professional administration. Each formulation varies in concentration and should be used according to prescribed guidelines.
Patients should be instructed to initiate therapy at the first sign of herpes symptoms. Drinking plenty of water helps reduce the risk of renal complications. Adherence to the prescribed dosing schedule is essential for efficacy. Patients should be advised about potential side effects and the importance of reporting any unusual symptoms to their healthcare provider.
Aciclovir is contraindicated in patients with known hypersensitivity to the drug or its components. Caution is needed in patients with existing renal impairment due to the increased risk of toxicity. Intravenous use is contraindicated in patients who are unable to tolerate oral or enteral forms of medication. Concurrent use with other nephrotoxic drugs must be evaluated thoroughly.