Why is Valtrex prescribed?
Valtrex is used to treat certain herpes infections, including herpes
zoster (the painful rash known as shingles), genital herpes, and herpes
cold sores on the face and lips.
Most important fact about Valtrex
Valtrex should not be used by anyone with a weak immune system, such
as those with HIV infection or those who have undergone a bone marrow or
kidney transplant. Valtrex can cause serious side effects, including
death, in such people.
How should you use Valtrex?
If you are taking Valtrex for shingles, you should start using it as
soon as possible after your doctor has made a diagnosis. It's best to
see a doctor and start the drug within 48 hours of first noticing the
rash. If you wait more than 72 hours after you first get a herpes zoster
rash, Valtrex may not be effective.
If you are using Valtrex for genital herpes, begin taking it at the
first sign of an attack. The medication may not be effective if you wait
longer than 72 hours after the first attack or 24 hours after a later
attack.
If you are taking Valtrex for cold sores, you should start using it
at the earliest signs of infection, such as tingling, itching, or
burning. If you wait until the cold sore develops, Valtrex might not
work.
You may take Valtrex with or without food.
--If you miss a dose...
Take it as soon as you remember. If it is almost time for your next
dose, skip the one you missed and go back to your regular schedule. Do
not take 2 doses at the same time.
--Storage instructions...
Store at room temperature.
Valtrex side effects
Side effects cannot be anticipated. If any develop or change in
intensity, inform your doctor as soon as possible. Only your doctor can
determine if it is safe for you to continue using Valtrex.
Why should Valtrex not be prescribed?
Avoid Valtrex if you are sensitive to it or the similar drug
acyclovir (Zovirax).
Special warnings about Valtrex
High doses of Valtrex have proved dangerous in people whose immune
system is compromised because of HIV infection, bone marrow transplant,
or kidney transplant.
If your kidneys are not functioning properly, or you are taking drugs
that may damage the kidneys such as Neomycin or Streptomycin, Valtrex
can make your condition worse or affect your central nervous system
(brain and spinal cord).
Effects on the central nervous system are more common in older
adults, leading to such symptoms as agitation, confusion, and
hallucinations. Their kidneys are also more likely to be affected; and
those with kidney problems need a smaller dose. In addition, older
adults tend to suffer the pain of shingles for a longer time after
healing has begun.
Valtrex relieves the symptoms of genital herpes, but it is not a
cure. There's also no evidence that it will prevent transmission of the
disease. To avoid spreading the infection, don't have sexual intercourse
during a flare-up.
Valtrex is not intended for use in children.
Possible food and drug interactions when taking Valtrex
If you are taking Valtrex with certain other drugs, the effect of
either drug could be increased, decreased, or altered. Check with your
doctor before combining Valtrex with cimetidine (Tagamet) and/or
probenecid (Benemid).
Special information if you are pregnant or breastfeeding
The effects of Valtrex during pregnancy and breastfeeding have not
been adequately studied. If you are pregnant or plan to become pregnant,
notify your doctor immediately. If you are nursing and need to use
Valtrex, your doctor may advise you to discontinue breastfeeding while
using Valtrex.
Recommended dosage for Valtrex
SHINGLES
The usual dose is 1 gram 3 times a day for 7 days.
GENITAL HERPES
The usual dose for the first attack is 1 gram twice a day for 10
days. For later attacks, the dose is 500 milligrams twice a day for 3
days. To keep the condition from returning, the dose is 1 gram once a
day. If you've had less than 10 infections per year, your doctor may
prescribe 500 milligrams once a day. The safety and effectiveness of
Valtrex treatment beyond 1 year have not been studied.
Patients with kidney problems or HIV infection may need a reduced
dosage.
COLD SORES
The recommended dosage is 2 grams twice a day for 1 day, taken about
12 hours apart. Valtrex should not be taken for more than 1 day. The
elderly and people with kidney problems may need a reduced dosage.
Overdosage
When taken by people with kidney disorders, excessive doses of
Valtrex have been known to cause psychological problems and kidney
failure. If you suspect an overdose, check with your doctor immediately.
