Aciclovir adverse effects

Vidarabine (adenine arabinoside, ara-A) is phos-phorylated in the cell to the triphosphate derivative which blocks DNA synthesis by inhibiting DNA polymerase. It is indicated for infections with herpes simplex virus and varicella-zoster however its use has to a large extend been surpassed by aciclovir. It is administered topically or intravenously. It is inactivated rapidly by adenosine deaminase which for systemic use necessitates constant infusion of the drug. Vidarabine is the least toxic of the purine analogues. Nausea and vomiting are the most frequent adverse effects and neurotoxicity may occur. 

Reversible psychiatric adverse effects have been described in three dialysis patients receiving intravenous aciclovir (8-10 mg/kg/day) (1). 

ACICLOVIR/ VALACICLOVIR H2 RECEPTOR BLOCKERS -CIMETIDINE t efficacy and adverse effects of antivirals Competition for renal excretion Use doses >4 g/day valacidovir with caution or consider alternative acid suppression. For doses <1 g/day, interaction is not thought to be clinically significant. Studies available only for valacidovir... 

Foscamet is used i.v. for retinitis due to CMV in patients with HIV infection when ganciclovir is contraindicated it has also been used to treat aciclovir-resistant herpes simplex virus infection (see p. 258). It causes numerous adverse effects, including renal toxicity, nausea and vomiting, neurological reactions and marrow suppression. 

Various local adverse effects of aciclovir eye-drops have been reported, including pruritus, burning sensations, and irritative or allergic conjunctivitis. Persistent superficial punctate keratitis, delayed epithehal healing, and epithelial dysplasia can develop (29). 

In a study of oral famciclovir versus oral aciclovir, designed to demonstrate equivalence of efficacy of the two drugs in the treatment of mucocutaneous Herpes simplex infection in HIV-infected individuals, there was no difference in the incidence or nature of adverse effects in the two groups (1). None of the withdrawals from the trial was considered by the investigator to be related to the study medication. 

To evalnate whether mycophenolate mofetil is effective in treating moderate to severe atopic dermatitis, an open pilot stndy was condncted in 10 patients (34). There were no serions adverse effects, bnt one patient had to discon-tinne treatment becanse he developed Herpes simplex retinitis, which resolved after treatment with aciclovir. Althongh there is no direct evidence that mycophenolate mofetil is a major canse of Herpes retinitis, in this patient it seems likely that it was dne to immunosuppression. In contrast, in vivo and in vitro mycophenolate mofetil strongly potentiates the antiherpetic effects of aciclovir, ganciclovir, and penciclovir (35). It is probably therefore enough to give antiviral therapy only when clinical signs of Herpes infection occur. 

Adverse effects of valaciclovir, the L-valyl ester of aciclovir, can be associated with increased drug concentrations when the dose is not adjusted for reduced renal function. For example, aseptic meningitis has been associated with valaciclovir in a patient with renal insufficiency (12). 

Oka strain Varicella vaccine (Merck) has been evaluated in immunocompromised children with leukemia in remission (6,7). Most children had chemotherapy stopped 1 week before and 1 week after immunization glucocorticoids were also stopped for 3 weeks (from 1 week before to 2 weeks after immunization). Varicella vaccine was safe, immunogenic, and effective in leukemic children at risk of serious disease or death from chickenpox. The major adverse effect was a mild rash in 50% of the children within 1 month of immunization, about 40% of whom were treated with aciclovir. A mild form of Varicella developed in 14% of immunized children exposed to Varicella (household contacts). The vaccine protected completely against severe Varicella. Leukemic vaccinees were less likely to develop zoster than were comparable children with leukemia who had wild tjrpe Varicella. 

Prompted by a case of increased theophylline adverse effects in a patient given aciclovir, a study was carried out in 5 healthy subjects who were given single 320-mg doses of theophylline (as 400 mg of aminophylline) before and with the sixth dose of aciclovir 800 mg five times daily for 2 days. The AUC of the theophylline was increased by 45% and its total body clearance was reduced by 30% by the aciclovir. ... 

Evidence appears to be limited to this report. However, be alert for an increase in adverse effects of theophylline (nausea, headache, tremor) if aciclovir is added to established treatment, and consider monitoring levels. More study is needed. 

MYCOPHENOLATE ANTIVIRALS -ACICLOVIR, GANCICLOVIR t plasma concentrations of both drugs. Toxic effects of both drugs likely Attributed to competition for renal tubular excretion Monitor blood counts - For signs and symptoms of immunosuppression, see Oinical Features of Some Adverse Drug Interactions, Immunosuppression and blood dyscrasias... 

Idoxuridine was the first widely used antivirus drug. It is superseded by aciclovir and is variably effective topically for ocular and cutaneous herpes simplex with few adverse reactions. 

The effects of aciclovir and valaciclovir for anogenital herpes have been studied in HIV-infected individuals in two controlled trials (5). In the first study, 1062 patients with CD4-I- counts over 100 x 10 /1 received valaciclovir or aciclovir for 1 year and were assessed monthly. In the second study, 467 patients were treated episodically for at least 5 days with valaciclovir or aciclovir and were assessed daily. Valaciclovir was as effective as aciclovir for suppression and episodic treatment of herpesvirus infections. Hazard ratios for the time to recurrence with valaciclovir 500 mg bd and 1000 mg od compared with aciclovir were 0.73 (95% Cl = 0.50, 1.06) and 1.31 (0.94, 1.82). Valaciclovir 1000 mg bd and aciclovir had similar effects on the duration of infective episodes (HR = 0.92 Cl = 0.75, 1.14). The most common adverse events, which occurred at similar rates with all regimens, were diarrhea, headache, infections, rashes, nausea, rhinitis, pharyngitis, abdominal pain, fever, depression, and cough. 

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