What specific acyclovir side effects were experienced?

How common are the most reported acyclovir side effects?
Acyclovir is generally well tolerated, but some patients report nausea, headache, and diarrhea as frequent complaints. These gastrointestinal and neurologic symptoms appear in roughly 5–10 % of users across clinical studies.

What severe reactions have patients described?
Rare but serious events include acute kidney injury, hallucinations, and seizures. These occur mainly in people with reduced kidney function or high intravenous doses.

Why do kidney problems develop with acyclovir?
The drug can crystallize in the renal tubules, especially when hydration is low or the patient is taking other nephrotoxic medicines.

What happens if someone notices blood in urine or reduced output?
Stop the medication and seek medical care immediately. Early recognition often reverses the damage.

Can acyclovir cause neurological symptoms?
Yes. Confusion, tremor, and hallucinations have been documented, particularly in elderly patients or those with impaired clearance.

What alternatives do patients switch to if acyclovir causes problems?
Valacyclovir and famciclovir are common substitutes that convert to acyclovir once inside the body, offering similar antiviral activity with simpler dosing.