Can You Take Acyclovir For Herpes Infection During Pregnancy?

Acyclovir During Pregnancy

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If you are diagnosed with the herpes-simplex or varicella-zoster viral infections, your doctor may prescribe antiviral medications. One such widely used drug is acyclovir.

This MomJunction post will tell you if this medication is safe to use during pregnancy, and if there are any risks associated. We also answer a few frequently asked questions about taking this medicine during pregnancy.

What Is Acyclovir?

Acyclovir is an antiviral medication useful for treating and preventing recurrence of genital herpes (caused by herpes simplex virus) and chicken pox and shingles (caused by the varicella-zoster virus). It is also approved for treating those with a weakened immune system such as those with HIV. Though it does not eliminate the viruses, it will reduce the intensity and severity of the infection by preventing the onset of symptoms such as sores or blisters.

Acyclovir is sold under the brand name Zovirax and is available in the form of oral tablets, intravenous injections, and topical ointments (1).

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Can You Take Acyclovir (Zovirax) During Pregnancy?

Yes, it is safe to take acyclovir during pregnancy, but you should consult your doctor before considering it.

Acyclovir is listed as a Category B drug by the US Food and Drug Administration (FDA). This means that there are no known harmful side effects. It is not known to increase the risk of congenital disabilities or pregnancy complications even when taken during early pregnancy (2).

Studies on the effects of acyclovir during second and third trimesters are limited. Therefore, they are prescribed during the last two trimesters only if their benefits outweigh the risks.

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How Much Acyclovir Is Safe To Take During Pregnancy?

The appropriate dosage for treating genital herpes is 400mg thrice a day or 200mg five times a day for 7-10 days (3).

Doctors usually prescribe the medicine when you experience the first episode of herpes during pregnancy. Everyday usage in the last four weeks of pregnancy will reduce the risk of outbreak, and prevents transmission to the newborn.

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What If You Have Already Taken Acyclovir (Zovirax) During Pregnancy?

If you have been on acyclovir even before your pregnancy, or have taken it without prescription, then let your doctor know about it. They can decide whether or not you should continue with the drug, or cut it down to the lowest possible dosage. Do not stop taking the medication suddenly.

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What Could Be The Side Effects Of Acyclovir During Pregnancy?

The potential side effects of taking acyclovir include diarrhea, nausea, headache, fever, hair loss, changes in vision, and stomach upset. These symptoms will resolve in a few days, and might not require a doctor’s attention.

However, you might have to see the doctor in the case of some serious side effects, such as

  • Allergic reactions including itching, skin rash, swollen lips, tongue or face
  • Confusion, hallucinations, and tremors
  • Increased sensitivity to sunlight
  • Difficulty in passing urine or dark urine
  • Chest pain
  • Seizures
  • Blistering, peeling, redness or loosening of the skin
  • Yellowing of skin or eyes
  • Difficulty in sleeping
  • Bloody diarrhea
  • Stomach pain or cramps
  • Numbness or tingling sensation in the arms or legs (4)

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General Precautions To Follow While Taking Acyclovir

Though it is safe to take the prescribed dosage of Acyclovir, a few precautions help you stay safe.

  • Tell your doctor if you have nerve, liver, kidney or electrolyte abnormalities.
  • Avoid taking the medication if you experience any symptoms of allergy after taking medicine.
  • Consume more water while you are on the medication to prevent any side effects.
  • Do not exceed the suggested dosage of the medication. Contact your doctor if you have accidentally taken more than the recommended dosage.

Next, we answer a few queries commonly asked by our readers.

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Frequently Asked Questions

1. Does acyclovir affect the birth control pill?

There are no studies on the interaction between acyclovir and birth control pills, so your doctor might prescribe them together.

2. Is it safe to use acyclovir (Zovirax) cream during pregnancy?

Yes, acyclovir cream is considered safe during pregnancy. It is often used to treat cold sores, where a small amount is applied to the affected area (5).

Acyclovir works best when taken at an early phase of infection. You should not ignore the course of medication once you begin the treatment. If the symptoms are not improving, check with your doctor for the further course of treatment.

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Did your doctor prescribe acyclovir for treating genital herpes during pregnancy? Share your experiences with us in the comments section below.


1. Acyclovir; US National Library of Medicine; 2017
2. Amy Crawford-Faucher; Acyclovir Safe for Treating Herpes Infection in Early Pregnancy; American Family Physician; 2011
3. SanjaKupesicPlavsic; Step by Step: Case Studies in Obstetrics & Gynecology; p. 175
4. Acyclovir; US National Library of Medicine; 2017
5. Cold sores in Pregnancy and Breastfeeding; NSW Medications in Pregnancy and Breastfeeding Service; 2016


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Rebecca Malachi

She is a Biotechnologist with a proficiency in areas of genetics, immunology, microbiology, bio-engineering, chemical engineering, medicine, pharmaceuticals to name a few. Her expertise in these fields has greatly assisted her in writing medical and life science articles. With 8+ years of work experience in writing for health and wellness, she is now a full-time contributor for She is passionate about giving research-based information to readers in need. Apart from writing, she is a foodie, loves travel, fond of gospel music and enjoys observing nature in silence. Know more about her at:
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