Aciclovir 400mg tablets

Aciclovir 400mg tablets

Aciclovir is the medical name for the active ingredient in the tablets. Aciclovir is an antiviral medicine which stops Herpes viruses from multiplying and spreading. For essential information about cold sores and their treatment read our medical information page.

Aciclovir tablets come in various strengths, 200mg, 400mg, and 800mg. A 5-day course of 200mg strength tablets is the recommended course for cold sore treatment. Various brands of tablets are available and produced by different drug companies, including Boots, GSK (Zovirax brand), and Actavis. All have the same active ingredient. The shelf life of the medication is several years, which means that people who are prone to cold sores can keep a stand-by supply at home for use as needed.

If you get repeated outbreaks (more than 6 a year) you may want to consider taking treatment to try and suppress these outbreaks by taking a 400mg tablet twice daily for 6-12 months.

How to take for outbreaks
Take one 200mg tablet 5 times a day at 4 hourly intervals for 5 days, swallowed whole, with or without food. Alternatively, dissolve the tablet in a glass of water and stir before drinking. Start tablets as soon as possible after the first signs of a cold sore. It is best to start at the stage when there is tingling and burning, even before the sore is visible. Tablets will still have an effect if started later, but results are best with early treatment. Continue for the full 5-day course. If a tablet is missed, take the next as soon as remembered. Do not take extra tablets to make up for missed doses. Avoid dehydration and drink plenty of water during treatment.

How to take for suppression
Take one 400mg tablet twice a day for 6-12 months, swallowed whole or dissolved in water. Remember to drink plenty of water to avoid dehydration.

When to consult a doctor
Most people who suffer from repeated cold sores are familiar with their symptoms and can safely self-treat. People who have not previously had sores on their lips or have sores that have not healed after 10 days should consult a doctor. Cold sores are often painful and are sometimes associated with mild symptoms of unwellness. They do not spread out across the face or cause fever and other symptoms of infections.

Aciclovir may not be suitable for people with a history of seizures or kidney disease. Aciclovir can interact with some prescribed medicines such as probenecid used to treat gout and cimetidine for acid indigestion, and also increase the dose received of theophylline and aminophylline sometimes used for asthma. These and other more theoretical interactions with mycophenolate, ciclosporin, and zidovudine are unlikely to be significant at the dose used to treat cold sores. You may need to discuss taking aciclovir alongside these medications with your doctor. Checks are carried out during the online consultation.

Aciclovir 400mg tablets side effects
Not everybody gets side effects. The most common, occurring in less than 1 in 10, are dizziness, headache, irritation, rash, itching skin, tiredness, nausea and sickness, diarrhoea, stomach pain, fever, and skin reaction after exposure to light (photosensitivity). See the manufacturer’s leaflet for a full list of side effects. If there is a very rare allergic-type reaction with swelling of the lips, face, or eyelids, or shortness of breath with wheezing, stop taking tablets and seek immediate medical assistance.

Pregnancy and breastfeeding
The risks are unknown, therefore, do NOT take aciclovir whilst pregnant or breastfeeding without first consulting a doctor.

See BUMPS use of medicines in pregnancy factsheet – Aciclovir.