Acyclovir (Buccal Mucosa)

Acyclovir is an antiviral medication primarily used to treat the herpes simplex virus.


Acyclovir is one of the most commonly used treatments for herpes simplex around. Emerging in the 1970s, it became popular due to its low cytotoxicity and extreme selectivity. Unlike other antivirals, acyclovir specifically targets the herpes virus and leaves just about everything else alone. This prevents many side effects from occurring on a regular basis and makes the drug ideal for a wide range of diseases. Additionally, it is safely combined with other drugs in order to improve the quality of treatment and prevent relapses.

Herpes viruses are extremely common and almost all people have contracted at least one. Often, people may have more than one herpes virus without being aware of the multiple infections. Someone could easily have herpes simplex without showing any symptoms. For these reasons, doctors are often the first ones to tell their patients they need Acyclovir treatments. In these circumstances, acyclovir is often the best way to prevent various forms of cancer commonly associated with complications of HSV 1 and 2. Most people hosting the herpes simplex virus are asymptomatic, even though they can spread the disease. Acyclovir helps prevent herpes outbreaks and the spread of herpes throughout the body.

Conditions treated

Type of medicine

  • Antiviral

Side Effects

Acyclovir can be given to patients topically or through systemic therapy. Both methods carry a number of risks associated with them and must be taken cautiously. Responsible use of acyclovir will result in few significant side effects. Some patients may experience nausea and discomfort from treatments, but these side effects shouldn't be a problem for the vast majority of patients. The risk of adverse side effects increases with dosage and duration of treatment. Patients taking high amounts of acyclovir are much more likely to face serious consequences from treatment.

Among the more serious side effects sometimes seen in patients are forms of encephalopathy. Patients taking high amounts of acyclovir are much more likely to suffer from headaches, hallucinations, and memory loss than those who take doses within a more moderate range. The deterioration happens in a very subtle way so many patients may not recognize it at first. Usually, it isn't until a family member or doctor sees the patient isn't able to perform important tasks that the encephalopathy is observed. The damage appears to be reversible with many patients making a full recovery with months of cessation.

Nephropathy, commonly known as kidney damage, can occur in extreme cases. Occasionally patients may see acyclovir crystals form in their kidneys and these crystals may prevent the kidneys from functioning properly. The kidney damage can make it difficult for patients to urinate and remove toxins from the body. This can cause hair loss, itching, lethargy, and anorexia to develop. Although the nephropathy is reversible, this damage is not necessarily so. Many patients will have to adjust to life after these side effects have settled. Generally catching the kidney damage at an early age makes it much easier for patients to make a full recovery.


Acyclovir is taken orally, but the results from using both methods are strikingly different depending on the disease. Oral bioavailability is very low, usually 15-30%, so relatively high doses of the drug are needed for serious treatment. Most often, the drug is useful for treating chickenpox. HSV largely manifests itself as red, itchy clusters across the mouth or genitals, but other parts of the body can be affected. Patients can use Acyclovir tablets to get rid of blotches for as long as they need. These tablets will gradually dissolve and release the medication you need to control herpes viruses.

The more potent means of using acyclovir as a systemic treatment is often used to treat cases of herpes simplex which appear to affect internal organs and significant bodily functions. For this use, most doctors like to take extra caution and prescribe Acyclovir to be taken over the course of a specific period. The effectiveness of systemic treatment varies with the virus. Herpes simplex 1 appears to be the most likely to respond to treatment while herpes simplex 2 is the least likely to respond well to acyclovir. Although some viruses in the herpes family are unlikely to respond to treatment, but Acyclovir's slow release can be combined with other antivirals to increase the potency of doses. However, dosing in this manner can cause a number of problems for patients.


Acyclovir is well known for interacting with other antiviral drugs. Interferon and ketoconazole are the drugs more often used with acyclovir because they are known to have similar activity towards herpes viruses. Though the mechanisms behind that activity is different from acyclovir, they will both help patients control the occurrence of attacks. Their effectiveness varies widely based on the specific species in question. HSV 1, and to a lesser extent HSV 2, is easily treated by an acyclovir and interferon combination, but ketoconazole does not appear to have much effectiveness beyond herpes simplex.

Zidovudine works well with acyclovir for patients who have HIV. Unfortunately, HIV patients do not have the ability to use most antivirals the way healthy people may. They must pick options that will work with their compromised immune systems in order to give them a better chance against fighting infections. Although the synergy between acyclovir and zidovudine is excellent, it also produces many serious health problems for patients. Kidney damage is often present, but an even greater concern is neurotoxicity. Patients often experience months of lethargy and fatigue when attempting to combine these two drugs together.


Although this drug is perfectly safe to use within its therapeutic index, it has the potential to cause serious problems if mishandled. These dangers are generally avoidable or reversible, but some of them can have serious side effects if allowed to go on unchecked. This drug is one of the most precise antiviral drugs on the market, so its dangers are generally related to filtration and the skin.

Patients who use excessive amounts of acyclovir are at risk of developing reversible kidney damage. The damage has the ability to lead to hair loss, fatigue, and other symptoms. These symptoms will generally go away if the patient ceases to use acyclovir for at least a couple of weeks. For patients with chickenpox, this isn't much of a concern because acyclovir treatments usually won't last beyond the initial onset of symptoms, but it can be problematic for herpes simplex infections. These infections must be treated over the lifetime of the patient and that increases the risk of kidney failure. However, doctors can monitor patients and help them understand what dangers their kidneys face. If anything serious begins to happen, most doctors will quit treatment and try to find something else to treat the disease of the patient.

Pregnant women can safely use acyclovir without fear of any birth defects. Studies of mice have shown acyclovir appears to present no harm to a developing fetus and there are hardly any reports of birth defects in medical records. In fact, most doctors recommend women use acyclovir to treat herpes simplex while pregnant because it is the safest method of treatment. Acyclovir can be given to babies and children without much worry either in small doses. It is recommended that children be given acyclovir as soon as they show signs of herpes. This prevents the onset of outbreaks later in life in those who are vulnerable to it.

Although resistance is generally rare in the healthy population, at least 10% of the immunodeficient will experience resistance to the drug. These patients will show little improvement unless they are given large doses of the drug over the course of months without any breaks or missed doses. Often, doctors will combine Acyclovir with another antiviral treatment in order to give patients the maximum utility they possibly can. However, this is always risky especially for a patient with immunity issues. The combined antivirals have the potential to wreak havoc upon many vital organs. The specific ratio of acyclovir and the alternative medicine is closely watched.


The most important thing to remember about storing acyclovir is to keep it somewhere cool and dry. You don't want heat or moisture ruining the medicine before it used or attracting insects. Generally, a shelf or refrigerator is a great place. Additionally, you need to make sure you do everything you can to keep children and pets away from it. They can injure themselves or damage your medicine. Ideally, a high shelf will keep them from accessing the drug while allowing you to easily access it. If you have finished using all Sitavig tablets, place any empty bottles away from where they are easily accessed by children and pets.

After a patient finishes an acyclovir treatment, it's to get rid of the remaining bottles and medicine. There is no need to keep it around and used syringes can act as reservoirs for bacteria. Although there are appropriate ways to dispose of medical waste, throwing them in your trash isn't one of them. Consult your doctor about finding the appropriate way to remove of any acyclovir bottles you haven't used. He will help you find the resources necessary to get rid of it and inform of the proper way to contain medical waste.


Acyclovir is one of the most popular antiviral treatments out there. It's used to treat viruses with the herpes family with a level of precision other drugs generally don't have. Unlike many other highly effective treatments acyclovir is one of the safest treatments anybody can receive. It has few side effects at low doses and the majority of its side effects can be reversed if patients abstain from treatment over the right period of time. Acyclovir can be combined with other drugs, but this can bring considerable dangers.

For herpes simplex viruses 1 and 2, Acyclovir is one of the most efficient treatments available. These viruses are known to cause serious harm over the long term without giving patients any obvious signs in their early stages. This treatment provides one of the best options for preventing any long term harm. The prevalence of herpes viruses makes this one of the most widely used and important antiviral drugs around. It has the ability to save the life of a patient and it can help curb the spread of disease between people. Despite the years of using this drug remains just as effective as it was when first developed. None of the viruses used to treat this disorder appear to have grown resistant to it. Its mechanism of action makes it almost impossible for herpes viruses to gain immunity to its effects.

Last Reviewed:
December 10, 2017
Last Updated:
April 04, 2018