Acyclovir

How it works

     * Acyclovir is an antiviral drug that has activity against herpes
       simplex virus types 1 (HSV-1), 2 (HSV-2), and varicella-zoster
       virus (VZV).
     * Acyclovir works in a number of different ways to prevent these
       viruses from replicating. Activity against HSV is greater than
       activity against VZV.
     * Acyclovir belongs to the class of medicines called antivirals.

Upsides

     * Acyclovir may be used in the treatment of herpes zoster virus
       (shingles). Acyclovir does not completely rid the body of the
       herpes zoster virus.
     * Acyclovir may be used to treat initial and recurrent episodes of
       genital herpes. Acyclovir does not cure genital herpes or
       completely rid the body of the herpes virus.
     * Acyclovir may be used in the treatment of varicella (chickenpox).
     * Acyclovir is available in a number of different formulations
       including a tablet, capsule, suspension, buccal tablet, cream, and
       injection.
     * Generic acyclovir is available.

Downsides

   If you are between the ages of 18 and 60, take no other medication or
   have no other medical conditions, side effects you are more likely to
   experience include:
     * Nausea, vomiting, diarrhea, headache, and a general unwell feeling.
       Buccal tablets may cause mouth pain. Rarely, acyclovir may affect
       your kidneys or cause a bleeding disorder.
     * May not be suitable for some people, including those with kidney
       problems, who are immunosuppressed, taking certain medications, or
       in those who are dehydrated.
     * Acyclovir is usually dosed five times daily.
     * May interact with a number of other medications including
       probenecid, other antivirals, medications for bowel disease,
       injectable osteoporosis medications, and analgesics.

   Notes: In general, seniors or children, people with certain medical
   conditions (such as liver or kidney problems, heart disease, diabetes,
   seizures) or people who take other medications are more at risk of
   developing a wider range of side effects. For a complete list of all
   side effects, [84]click here.

Bottom Line

   Acyclovir is an antiviral drug that helps treat chickenpox, genital
   herpes, and shingles infections. It is most effective when started
   within 48 hours of symptom onset.

Tips

     * Acyclovir treatment is best started within 72 hours of symptom
       onset (ie, rash, blisters, tingling, burning) and most effective if
       started within 48 hours of symptom onset.
     * Take acyclovir for the exact time prescribed by your doctor, even
       if your symptoms improve. Although acyclovir treats viruses, it is
       not effective against the flu or the common cold.
     * Shake acyclovir oral suspension well before using. Use a proper
       dosing syringe or medicine cup to correctly measure dosage, not a
       kitchen teaspoon.
     * If you have been prescribed buccal tablets to treat a cold sore,
       place the flat side of the buccal tablet against your upper gum,
       behind your lip and in front of your canine tooth on the same side
       of your mouth as the cold sore. Close your mouth and gently press
       on the outside of your lip to hold the tablet in place for 30
       seconds. Allow the tablet to slowly dissolve; eating and drinking
       may continue as normal while the buccal tablet is in place, but
       avoid brushing your teeth, chewing gum, or wearing an upper
       denture.
     * If you are taking acyclovir long-term and your weight changes, let
       your doctor know as acyclovir dosages are based on weight.
     * Try to maintain good hydration when taking acyclovir.
     * If you have a shingles rash or a cold sore, try and keep it as
       clean and dry as possible; although you must be careful not to
       transfer the virus to others, so always use disposable tissues or a
       separate towel that is washed by itself. Wearing loose clothing may
       help prevent irritation of a shingles rash.
     * Seek urgent medical advice if you have any signs of an allergic
       reaction (such as hives; difficulty breathing; facial or throat
       swelling), easy bruising or bleeding or difficulty urinating,
       swelling in your feet, or shortness of breath.
     * Herpes infections are highly contagious and you should cover your
       rash and avoid intimate contact. Also, avoid touching the rash and
       then your eyes. Wash hands frequently.
     * If you are taking acyclovir for genital herpes, it will not prevent
       you from passing the infection to your sexual partner. Sexual
       intercourse should be avoided while you have lesions or the first
       symptoms of an outbreak. Even if you have no symptoms, transmission
       of genital herpes may still occur.
     * Talk to your doctor or pharmacist before buying any medication over
       the counter to check that it is compatible with acyclovir,
       including vitamins or herbal products.
     * Acyclovir may make your skin more sensitive to the sun and more
       likely to burn. Wear at least an SPF 30+ sunblock and
       sun-protective clothing when you need to go outside.

Response and Effectiveness

     * May take up to two hours to reach peak plasma concentrations after
       oral acyclovir administration.
     * May take up to three days for symptom reduction; however, acyclovir
       should be taken until the course prescribed is completed. Acyclovir
       works best when started within 48 hours of symptom onset.
     * In herpes zoster (shingles) infections, acyclovir shortened to time
       it took lesions to scab over and decreased the time needed for the
       rash to heal and become pain-free. Adults older than 50 gained the
       most benefit from taking acyclovir.
     * In varicella infections (chickenpox), acyclovir shortened the time
       to 50% healing, reduced the number of lesions and vesicles, and
       decreased rates of fever and tiredness by day 2.

References