What is a common side effect of acyclovir that a patient should be aware of?

Acyclic is a widely used antiviral medication primarily for the treatment of herpes simplex virus infections, shingles, and varicella-zoster virus. One of the notable concerns with acyclovir is its potential to cause renal toxicity, particularly when administered intravenously or in high doses. This occurs because acyclovir is excreted through the kidneys, and in situations where hydration is inadequate or the patient has pre-existing renal impairment, it can lead to crystallization in the renal tubules, resulting in damage.

Patients on acyclovir should be educated about the signs of renal toxicity, including changes in urinary output, hematuria (blood in urine), or elevated blood urea nitrogen (BUN) and creatinine levels. Ensuring adequate hydration during treatment can help mitigate this risk.

The other options, while they may be associated with various medications or other conditions, are not the primary concerns with acyclovir. Nausea and drowsiness can occur but are less commonly highlighted compared to renal issues, and increased appetite is not typically a side effect linked to acyclovir. Thus, understanding the risk of renal toxicity is crucial for anyone undergoing treatment with this antiviral agent.