Famvir (Famciclovir) Dosage and Side Effects
FAMVIR is used to treat herpes zoster (shingles). FAMVIR is used to treat or prevent recurrence of the viral infections which cause genital herpes.
Proper Use of this medication
How do I use FAMVIR?
You should take FAMVIR only as directed by your doctor. Do not take more of it, do not take it more often and do not take it for a longer period of time than your doctor ordered.
Be sure to take FAMVIR regularly as prescribed. Try to take your tablets at the same time each day. You should continue to take your medicine even if you do not feel better, as it may take a few days for your medicine to work.
If your kidneys are not working very well, your doctor will probably have you take this medicine less often, check with your doctor if you have kidney problems.
FAMVIR will work whether or not you take it with food. You should swallow the tablets whole, with water. Do not chew them.
How long do I use FAMVIR?
The usual adult dose is one FAMVIR tablet three times a day for shingles. Follow your doctor’s instructions about how and when to take your tablets. Start taking them as soon as you can for the best effect.
Most people take one tablet when they get up in the morning, one in the middle of the afternoon and one before going to bed at night.
Finish all the tablets you have been given even if you start to feel better. The treatment lasts for seven days.
Treating an outbreak of recurrent genital herpes:
If you have had herpes infections of the genitals before (called recurrent genital herpes), your doctor may decide to treat the outbreak. You will likely be told to take 125 mg twice a day for 5 days or if you are HIV-positive, 500 mg twice a day for 7 days. Most people with recurrent genital herpes take one tablet when waking, and one tablet just before going to bed. FAMVIR should be taken as soon as possible after the early symptoms (pain, burning, blisters, itching, tingling) begin to appear.
Preventing outbreaks of recurrent genital herpes:
If you have had herpes infections of the genitals before (called recurrent genital herpes), then your doctor may decide to prevent future outbreaks. Your doctor will likely tell you that you should continually take 250 mg twice a day. Most people with recurrent genital herpes take one tablet when waking, and one tablet just before going to bed.
In case of drug overdose, contact a healthcare practitioner (doctor), hospital emergency department or regional poison control centre, even if there are no symptoms, Bring your pack of tablets with you.
Taking too much of any type of medicine is risky.
Taking too much FAMVIR may affect the kidneys. In people who already have kidney problems it may, rarely, lead to kidney failure if their dose is not correctly lowered.
Important: Your doctor may give you different instructions better suited to your specific needs. If you need more information on how to take FAMVIR properly, double-check with your doctor or pharmacist.
If you miss taking a FAMVIR tablet, don’t worry. Take it as soon as you remember. Take your next tablet at the normal time. However, do not take two doses within a time interval of less than 1 hour, in that case you should skip the missed dose. Carry on as normal until you have finished all the tablets. It is important that you finish all the tablets you have been given, unless your doctor tells you to stop taking them. Do not double-dose.
Any medicine can cause side effects. With FAMVIR, some people may feel sick or get a headache, or experience confusion or dizziness. Other side effects include drowsiness (usually in older people), hallucinations (seeing or hearing things that are not really there), vomiting, yellowing of the skin and/or eyes, abnormal liver function test results, palpitations (signs of abnormal heart beat), skin rash, itching or blistering, diarrhea, tiredness and abdominal pain. If you get these or any other problems while you are taking FAMVIR, tell your doctor or pharmacist.
Warnings and Precautions
Before you take FAMVIR, talk to your doctor if:
- You have an intolerance to some sugars, galactose intolrance, a severe lactase deficiency or glucose-galactose malabsorption, then you should not take FAMVIR, as this product contains latose
- You have an allergy (including itching) or other unwanted (side) effects when previously taking FAMVIR
- You are pregnant, planning to become pregnant or breastfeeding when using FAMVIR
- You have a past history or current kidney disease
- You have severe liver problems
- You have other medical conditions
It is important to tell your doctor, dentist or pharmacist if you are taking other medication, as combining drugs can sometimes result in a change from the expected drug effects, or cause harmful effects.
Interactions with this medication
Always tell your doctor about other medical conditions you have or any medicines you are taking. This means medicines you bought for yourself as well as medicines on prescription. Your doctor or pharmacist will know if it is safe to take FAMVIR as well.
It is particularly important that you tell your doctor or pharmacist if you are taking any of the following medicines:
Probenecid (used to treat high blood levels of uric acid associated with gout and to increase blood levels of penicillin-type antibiotics), or any other medicine that can affect your kidneys.
Raloxifene (used to prevent and treat osteoporosis).
You can take FAMVIR with or without food.