Valacyclovir vs Acyclovir – Which Is The Best Drug For Shingles?

This article explains the differences between Valacyclovir and Acyclovir, two antiviral medications that are used to treat cold sores around the mouth and shingles.

Shingles, also known as herpes zoster, is a common viral infection which is caused by the varicella-zoster virus. This virus is actually the same virus that causes chickenpox.

It causes a rash with blisters. The rash commonly occurs on one side of the body. About 33 percent of people will develop herpes zoster in their lifetime, with approximately 1 million cases every year in the US.


The symptoms of this condition generally affect only a small section of one side of the body. These symptoms may include:

  • headaches;
  • numbness or tingling;
  • nausea;
  • body aches;
  • fever and chills;
  • sensitivity to touch;
  • itching;
  • one-sided stabbing pain;
  • fluid-filled blisters which break open and crust over, typically on the torso or face;
  • a red rash that starts a few days after the pain.

This condition can occur in anyone who has had varicella (chickenpox), but some factors put individuals at increased risk of developing it. Risk factors include:

  • taking medicines that weaken the immune system, like – medications given after an organ transplant as well as having HIV/AIDS;
  • having had chemotherapy;
  • physical traumas;
  • emotional stress.


Valtrex is the brand name for this antiviral drug. It works by slowing the growth and spread of the virus, thus, the body can fight off the infection.

In 1995, it was approved for medical use and is manufactured by GlaxoSmithKline, a British pharmaceutical company with headquarters in London. In the United States, it is available as a generic drug since 2009.

Note – it will not cure herpes, however, it can lessen the symptoms of the infection and can help heal the rash more quickly. Additionally, it may help reduce how long pain remains after the sores heal.


It is used to treat and prevent recurrences of genital herpes as well as to treat cold sores. Also, it is used to treat shingles (herpes zoster), a viral infection affecting the skin. In children, it is used to treat chickenpox.


It comes as a tablet to be taken by mouth. To treat genital herpes, this medicine is commonly taken twice per day for 5 days. To treat shingles, it is typically taken three times a day (every 8 hours) for a week. It is most useful if it’s used within 48 hours of the onset of rash.

Side Effects And Precautions Of Valtrex 

Common side effects may include:

Rare side effects may include:

  • severe drowsiness;
  • delirium;
  • urinating less than usual;
  • depression;
  • swelling of the ankles, legs, or feet;
  • confusion;
  • aggressive behavior;
  • seizures;
  • agitation;
  • coma;
  • shaky movements;
  • encephalopathy (brain degeneration);
  • increased heart rate;
  • hallucinations.

If you are pregnant, talk to your healthcare provider about possible risks and benefits, since there are no conclusive studies regarding its safe use during this time.

Drug Interactions

It may interact with other medicines, including – cancer medicines, antiviral medicines, lithium, IV antibiotics, drugs used to prevent organ transplant rejection, methotrexate, medicines used to treat ulcerative colitis, and arthritis medicines.


It is the generic name for Zovirax, an antiviral medication that is useful against genital herpes (herpes simplex), herpes simplex 1 (cold sores), the cytomegalovirus (also referred as CMV), and herpes zoster virus (shingles).

The medicine works by preventing viruses from multiplying and dividing. In 1980, the Food and Drug Administration approved it for medical use to treat the above conditions.


It is typically used to treat and prevent reoccurrence of the herpes simplex virus and to treat shingles and chickenpox.

Other uses of this medicine include the prevention of cytomegalovirus infections (more than 50% of adults in the US have had this infection by age 40) following severe complications of Epstein-Barr virus infection and transplant.


The dose will depend upon the type of infection a patient has, hence, it is recommended to use it precisely as the healthcare provider instructs. The usual dose ranges from 200 to 800 mg, taken either 3, 4, or 5 times per day.

For the treatment of herpes zoster:

  • children up to 12 years of age – the dose must be determined by a healthcare professional;
  • children 12 years of age and older and adults should take 800 mg 5 times per day for 7 to ten days.

For maximum benefits, the treatment should be started within 48 hours of the onset of rash, however, the use of this drug may be started as late as 72 hours after lesions start to form.

Notethis medication doesn’t heal herpes zoster, but it can help the rash to heal more quickly.

Side Effects And Precautions Of Zovirax

Common side effects may include:

  • hair loss;
  • upset stomach;
  • dizziness;
  • vomiting;
  • joint pain;
  • changes in vision;
  • agitation;
  • tiredness;
  • diarrhea.

Rare side effects may include:

  • itching;
  • hives;
  • weakness;
  • blisters;
  • difficulty sleeping;
  • pale skin;
  • problems swallowing;
  • difficulty breathing;
  • aggressive behavior;
  • swelling of the throat, face, tongue, lips, feet, eyes, hands, or ankles;
  • decreased urination;
  • hoarseness;
  • difficulty speaking;
  • fast heartbeat;
  • tingling in the arms or legs;
  • a cough;
  • chills;
  • a sore throat;
  • fever;
  • seizures;
  • unusual bruising;
  • loss of consciousness;
  • a shaking of a part of the body;
  • confusion;
  • hearing voices that do not exist;
  • bloody diarrhea;
  • stomach cramps;
  • blood in the urine.

This medicine should be used with caution in:

  • individuals who wear contact lenses;
  • individuals at risk of dehydration;
  • individuals with abnormalities in the nervous system;
  • individuals with kidney problems.

Pregnancy & Breastfeeding

There are no clinical studies regarding its safe use by pregnant or lactating women.

Valacyclovir vs Acyclovir – Which Is The Best Drug For Shingles?            

Both medicines target the same viruses, however, valacyclovir provides a longer duration of action. Note – how long it takes for this medication to work depends on a few factors, like – how quickly you take it and the severity of the outbreak, hence, doses can be considerably fewer.

Both drugs have similar adverse effects.

Natural Remedies For Shingles

#1 Geranium Essential Oil

It reduces pain due to post-herpetic neuralgia following a herpes zoster outbreak.

#2 Apple Cider Vinegar

Topical use of apple cider vinegar on the skin can cure varicose veins, plaque, as well as reduces inflamed skin. In addition, the oral consumption of ACV speeds up the healing process of rashes.

#3 Oatmeal Baths

It helps calm your itching. For even better results, add colloidal oatmeal, which is produced from oats that have been ground to a fine powder.

#4 Nutrition

A weakened immune system worsens this condition. Vegetables rich in calcium and beta-carotene can boost immune function. In addition, onions and garlic also help enhance immune function due to their high content of allicin.

#5 St. John’s Wort

Due to its active constituents (like – hyperforin and hypericin), this herb has potent anti-inflammatory, nerve restorative, and nerve protective properties.

Images credit – @Getty & Shutterstock

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