Acyclovir Pills: Five Things You Should Know

Acyclovir, commonly manufactured by Zovirax, is used to treat infections caused by herpes viruses like genital herpes, cold sores around the mouth (herpes simplex), shingles (herpes zoster), and, in some cases, chickenpox. So, Acyclovir is antiviral, but it does not kill the virus rather it reduces the spread of infection, forming up of new spores, pain related to spores, and stuff like that. It can also increase your immunity to fight viruses.

In 2017, Acyclovir was the 166th most prescribed medicine in the USA with 3 million prescriptions. Howard Scheffer coinvented the drug Acyclovir while studying acycloadenosine as an antiviral drug with Robert Vince, S. Bittner, and S. Gurwara. Later, Schaeffer continued his work on acyclovir with Elion in Burroughs Wellcome. The U.S. patent of acyclovir was registered in 1979. The prescriptions started in 1981 onwards.

What are Acyclovir pills and how to use them?

So, every cell of our body has genetic material which is generally DNA. Similarly, herpes virus and poxvirus have DNA too. This DNA is composed of four nitrogenous bases Adenine, Guanine, Thymine, and Cytosine.

All these bases are mandatory for the formation of DNA and therefore all living life. Now, Acyclovir mimics viral Guanine. That is to say, when the virus comes in contact with Acyclovir, it misunderstands Acyclovir as Guanine and so, Acyclovir is added to the viral DNA chain instead of Guanine.

This stops the formation of the DNA chain, thus controlling the spread of the infection.

Doctors usually prescribe oral doses 2-5 times a day. Drinking plenty of fluids becomes necessary when taking any antiviral medicine (unless the doctor says otherwise). Also, by the mechanism mentioned above, you might’ve guessed that this medicine affects quantitatively. So, skipping doses is not a good idea. Always follow the doctor’s prescription regularly.

Five things you should know about the Acyclovir pill:

1.  Some side-effects: Side-effects can vary from person to person, but the general ones are: muscle pain, dizziness, drowsiness, nausea, agitation, general discomfort, headache.

2.  Who shouldn’t take Acyclovir pills?

People already suffering from dehydration and kidney malfunctions shouldn’t take Acyclovir pills on their own. If the doctor prescribes you Acyclovir, tell them if you are suffering from dehydration or kidney malfunctions. The medicine is heavy and may cause severe side effects if the quantity of water is not proper in your body.

3.  What conditions do Acyclovir pills treat?

According to, here’s a detailed list of conditions that Acyclovir pills treat:

1) chickenpox

2) a shingles outbreak that involves the eye

3) shingles

4) prevent shingles in the patient without a normal immune system

5) genital herpes

6) recurrent genital herpes

7) prevent recurrent herpes simplex infection

8) herpes simplex encephalitis

9) a herpes simplex infection of the skin, mouth, or genitals

10) herpes simplex infection of the skin and mucous membranes

11) a herpes simplex infection

12) a cold sore

13) herpes simplex virus infection throughout a newborn’s body

14) inflammation of the liver caused by herpes simplex virus

15) liver infection caused by the latent varicella-zoster virus

16) infection due to a virus

17) infection throughout the body due to listeria monocytogenes

18) herpes infection of the brain and surrounding tissue

19) treatment to prevent cytomegalovirus disease.

4.  Can you take Acyclovir pills during pregnancy and breastfeeding?

There is no perfect answer to this. Human trials are not sufficient at this time. On the same note, human trials have been conducted in some women and the result was the same as normal women. However, they are not enough to come to conclusions.

Keep in mind that Acyclovir is excreted during breastfeeding and can be found in breast milk. So, be sure to discuss this with your doctor if you’re planning to take Acyclovir during breastfeeding.

5.  Different preparations of Acyclovir.

● Capsules: 200 mg.

● Tablets: 400 and 800 mg.

● Suspension: 200 mg/5 ml.

● Injection: 50 mg/ml.

● Powder for injection: 500 and 1000 mg.

● Ointment: 5%.


In conclusion, no medicine, however common, should be taken without a Doctor’s prescription. However, it is also necessary to know completely about the medicines you use, so that you can ask healthy questions from your doctor.

Hope this helps!