Alternatives to Acyclovir for Genital Herpes in Patients with Acyclovir Allergy

First-Line Alternative Treatment

The Centers for Disease Control and Prevention recommends foscarnet 40 mg/kg body weight IV every 8 hours as the first-line treatment for patients with acyclovir allergy until clinical resolution is attained 2, 3
Foscarnet is effective for treatment of genital herpes in patients who cannot take acyclovir or its derivatives, with a recommended treatment duration until clinical resolution 1, 2
All acyclovir-resistant strains are also resistant to valacyclovir, and most are resistant to famciclovir, making these medications unsuitable alternatives for patients with acyclovir allergy 2, 3

Topical cidofovir gel 1% applied to the lesions once daily for 5 consecutive days may be effective for localized lesions, particularly useful for patients with mild disease who cannot tolerate systemic foscarnet 2, 3

The Centers for Disease Control and Prevention suggests topical cidofovir gel 1% once daily for 5 days as a treatment option for mild to moderate disease 2
Consider consultation with an expert in infectious diseases for management of mild to moderate disease 1

Intravenous foscarnet 40 mg/kg every 8 hours until clinical resolution is recommended for severe disease, with potential requirement for hospitalization 2, 3

Allergic reactions to acyclovir, valacyclovir, and famciclovir are infrequent but can occur, with desensitization to acyclovir as a potential option in consultation with an allergy specialist 1, 2
Patients should be monitored closely for adverse effects of foscarnet, which can include nephrotoxicity and electrolyte abnormalities 2

Immunocompromised patients with acyclovir allergy require close monitoring due to higher risk of severe disease, with potential requirement for higher doses of foscarnet 2, 3

Limited data exists on foscarnet use during pregnancy, with treatment decisions requiring careful consideration of potential risks and benefits, and consultation with maternal-fetal medicine specialists 1, 2

Patients should be advised to abstain from sexual activity while lesions are present, and educated about the natural history of genital herpes, including potential for recurrent episodes 4
Regular follow-up is essential to assess treatment response and manage potential adverse effects of alternative medications 2

Condom use should be encouraged during all sexual exposures, with patients advised about the risk of transmission even during asymptomatic periods, and partners informed about the infection and potential risks 4