Acyclovir Tablet (Zovirax) Side Effects in Pakistan

Acyclovir side effects — a complete guide. From common effects to serious warnings — everything you need to know is on this page.

Compiled by the PakVita Editorial Team · AI-assisted drafting with editorial review · Sourced from DRAP, WHO, BNF · Last updated: 2026-06-17

Side Effects

Quick Answer

Common side effects of Acyclovir include nausea, vomiting, diarrhea, headache, and dizziness. Serious but rare effects include kidney damage (nephrotoxicity) and neurological symptoms such as confusion — especially in patients with renal impairment or dehydration. Most patients tolerate Acyclovir well with adequate hydration. Contact your doctor immediately if serious symptoms appear.

Side Effects at a Glance

Common

Nausea (ji machlana)
Vomiting (qai)
Diarrhea (dast)
Headache (sar dard)
Dizziness (chakkar)

Serious — See a Doctor

Nephrotoxicity / crystalluria (kidney damage — especially with dehydration or high doses)
Neurotoxicity — confusion, tremor, agitation (especially in renal impairment)
Reversible renal impairment (high oral or IV doses)
Thrombophlebitis (IV route only)

When to See a Doctor Immediately

Confusion, agitation, or severe tremor
Reduced or absent urine output (renal damage)
Severe headache and neck pain (herpes encephalitis — EMERGENCY)
Skin rash, anaphylaxis signs (allergic reaction)
Symptoms worsening or no improvement with treatment

Acyclovir Tablet (Zovirax) Side Effects (Nuksanat)

Acyclovir is generally safe when given at the correct dose and when adequate hydration is maintained. However, like any medicine, side effects can occur in some patients.

Common Side Effects (Aam Nuksanat)

Nausea (ji machlana)
Vomiting (qai)
Diarrhea (dast)
Headache (sar dard)
Dizziness (chakkar)

These side effects are generally mild and improve with treatment. If they persist, inform your doctor.

Serious Side Effects (Sanjeedah Nuksanat)

Nephrotoxicity / crystalluria (kidney damage) — see a doctor immediately
Neurotoxicity — confusion, tremor, agitation — see a doctor immediately
Reversible renal impairment at high doses — see a doctor immediately

Hydration Warning (Pani ka khayal rakhein)

Acyclovir can form crystals in the kidneys if fluid intake is low — crystalluria and acute kidney injury can occur. Drink plenty of water with each dose — this is the most important precaution.

When to See a Doctor (Kab Doctor Se Milna Zaroori Hai)

Confusion, agitation, or severe tremor
Reduced or absent urine output (renal damage)
Severe headache + neck pain (herpes encephalitis — EMERGENCY)
Allergic reaction signs: rash, swelling, difficulty breathing

Warnings and Precautions (Ihtiyat)

Don't use Acyclovir if allergic to acyclovir or valacyclovir
Dose adjustment is required in renal impairment
Monitor kidney function in elderly patients
Use in pregnancy only on doctor's prescription

Side Effects Summary Table

Type	Side Effect	Action
Common	Nausea, vomiting	Monitor — inform doctor if severe
Common	Headache, dizziness	Monitor / inform doctor
Common	Diarrhea	Monitor / maintain hydration
Serious	Nephrotoxicity	See a doctor immediately
Serious	Neurotoxicity — confusion	EMERGENCY

Reporting Side Effects

If you notice any unexpected side effect, report it on the DRAP pharmacovigilance portal: https://www.dra.gov.pk/pharmacovigilance

The information in this guide is for educational purposes only. If you notice any side effect, contact your doctor or pharmacist.

Frequently Asked Questions

Acyclovir ke most common side effects kya hain?

The most common side effects include nausea, vomiting, diarrhea, headache, and dizziness. These are usually mild. If they persist, inform your doctor.

Kya Acyclovir allergic reaction cause kar sakta hai?

Yes, like any medicine acyclovir can cause an allergic reaction. Signs include rash, itching, swelling, or difficulty breathing. Stop immediately and see a doctor.

Kya Acyclovir kidney ko affect karta hai?

Yes — especially at high doses or with dehydration, kidney damage (nephrotoxicity) and crystalluria can occur. This is why drinking plenty of water with each dose is essential. Dose adjustment is required in renal impairment.

Acyclovir se side effect ho to kya karein?

For mild side effects, speak with your pharmacist. For serious side effects such as confusion, reduced urine output, or severe rash — stop the medicine immediately and see a doctor or go to hospital.

Kya Acyclovir liver ya kidney ko affect karta hai?

Acyclovir is primarily eliminated by the kidneys — dose adjustment is required in kidney disease. Significant liver-related toxicity is uncommon at normal doses. The doctor will advise based on test results.

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Sources

DRAP Registered Products Database — Drug Regulatory Authority of Pakistan
WHO Model List of Essential Medicines, 23rd ed. (2023) — World Health Organization
British National Formulary (BNF) — BMJ Group & Pharmaceutical Press

Medical disclaimer

This page is for educational use only and does not replace professional medical advice. Always confirm diagnosis, dose, and interactions with a qualified doctor or pharmacist before starting or changing any medicine.