Valtrex is used in the treatment of genital herpes
infections, and shingles (herpes zoster). It works by inhibiting the
reproduction of the herpes virus. Valtrex (valacyclovir) does not
cure herpes, but decreases the number of outbreaks and helps sores
Valtrex treatment should begin within 24 hours of the
first signs of a genital herpes outbreak, and within 48
hours of a shingles outbreak for maximum effectiveness. If
you wait more than 72 hours to start treatment Valtrex may not be effective. Individuals with recurrent
genital herpes are sometimes prescribed daily doses to
decrease the number of outbreaks. If daily Valtrex treatment is
undertaken for recurrent outbreaks, treatment should be
re-evaluated after a year.
Your doctor may
advise kidney function tests while you are taking Valtrex, use only as directed.
Valtrex 500 mg, brand name Virval manufactured by Novagl, comes in multiples of 10 tablets.
Common Valtrex Side Effects: Abdominal pain, dizziness, headache,
nausea, and vomiting.
Less Common or Rare Valtrex Side Effects: Acne, aggression, agitation, allergic
reaction, confusion, depression, diarrhea, fatigue, hair loss,
hallucinations, hepatitis, high blood pressure, increased heart
rate, insomnia, joint pain, mania, menstrual problems, muscle
cramps, nervousness, and swelling of the face. Contact your doctor
immediately if side effects are severe.
Cautions: Valtrex may not be a suitable treatment
for all individuals. Speak to your doctor if any of the
following conditions apply to you, as altered dosage,
additional monitoring, or alternative treatments may be
- Allergy: Notify your doctor and pharmacist of
any drug allergies. Do not take Valtrex if you are allergic
to it or if you are allergic to allopurinol.
- Bone Marrow Transplant: Do not use Valtrex if you have
had a bone marrow transplant. It may lead to serious side effects or
- Dehydration: Avoid dehydration while taking Valtrex.
- HIV Infection: Do not take Valtrex if you have an HIV
infection. May lead to severe side effects and fatality.
- Intercourse: Valtrex treats symptoms, but does not cure
herpes. To decrease the chance of spreading the virus, avoid sexual
intercourse while sores are present.
- Kidney Damage or Disease: Notify your doctor of kidney
problems. You may need a dosage adjustment.
- Kidney Transplant: If you have had a kidney transplant,
you should not take Valtrex. May result in acute side effects and
- Liver Cirrhosis: Do not take Valtrex if you have
cirrhosis of the liver.
- Nervous System Disorders: Discuss nervous system
disorders with your doctor.
- Weak Immune System: Do not take Valtrex if you have
problems with your immune system. It may lead to serious side
effects and death.
- Zovirax (acyclovir): Do not take Valtrex if you have
sensitivity to Zovirax.
Certain drugs react with Valtrex. Your doctor may adjust the
dosage of one of the medications, or may indicate that they should
not be taken together. Always consult your doctor
about potential drug interactions.
- Alcohol - May increase dizziness.
- Zidovudine - May cause lethargy and acute fatigue.
- Probenecid - If you are taking probenecid, notify your
doctor before taking Valtrex.
- Fosphenytoin -
Valtrex may decrease the effectiveness of fosphenytoin.
- Meperidine - May cause neurological problems when
- Depakote (valproic acid) - Valtrex may lower the effectiveness
- Dilantin (phenytoin) - Valtrex may decrease the effectiveness of
- Neomycin - Combining Valtrex with Neomycin may damage kidneys or
affect central nervous system.
- Cyclosporine - May increase risk of kidney
- Streptomycin - May cause kidney damage or affect the central
nervous system when combined with Valtrex.
- Cimetidine - If you take cimetidine, notify your doctor
before taking Valtrex.
- Varicella vaccine - Valtrex may lower the effects of
- Allopurinol - If you are allergic to allopurinol, you
may have an allergic reaction if you take Valtrex.
guidelines for adults are as follows:
- Shingles (herpes zoster); Usually 1 gram 3 times per day for
- Genital Herpes Outbreak; for the first outbreak the usual dosage
is 1 gram two times per day for 10 days. For subsequent outbreaks
the usual dose of Valtrex is 500 mg two times a day for 3 days. Suppressive
Therapy; May be 500 mg or 1 g per day for up to one year followed by
Your doctor may suggest a different dosage or frequency of use.
Always follow the instructions on your prescription, taking Valtrex as often, and for as long, as suggested
by your doctor.
If you have kidney function problems, your doctor may prescribe a
reduced dose or direct you to discontinue Valtrex treatment. Signs of
overdose include psychological problems and kidney failure.
Start Valtrex treatment as soon as possible, preferably within one day,
of a herpes or shingles outbreak. If you miss a dose, take it as
soon as you remember. If it is nearly time for your next dose, skip
the missed dose and resume your regular schedule. Do not take double
doses, or change your dose without permission from your doctor.
Valtrex may be taken with or without food.
Take Valtrex for as long as your doctor recommends, even
if you begin to feel better. Viral infections may still linger even
if the obvious symptoms have gone away. Still, you should not
continue treatment for any longer than your doctor suggests. If you
see no improvement towards the end of your treatment, contact your
doctor for further instructions.
Store Valtrex away from direct light and heat. Store tablets at
room temperature in a dry location; avoid storing them in the
bathroom, near sinks, or other areas where the container may become
damp. Do not use Valtrex after the expiration date.
Keep Valtrex away from children; both when storing it, and when
discarding any unused medication.
Notify your doctor if you are pregnant or plan to become
pregnant. The effects of Valtrex on the fetus are not known. The use
of Valtrex during pregnancy should be discussed with a
doctor, and only undertaken if the benefits of treatment outweigh
the possible risks to the infant.
Valtrex appears in breast milk. Discuss the risks with
Valtrex is not recommended for use in children.
Seniors should avoid dehydration while taking Valtrex. Your
doctor may prescribe a lower dose if you have kidney problems.
This document is provided for information only. It is not a
substitute for consultation with a physician, either to diagnose
symptoms or prescribe treatment. Any dosages mentioned are general
guidelines only, please follow the directions of your doctor exactly when taking
Valtrex. We have made every effort
to ensure that this information is accurate, but only your doctor can say if Valtrex, or a drug combination, is safe for you. It
should not be construed to indicate that to order and use
Valtrex is safe, appropriate, or effective for you. Consult
your healthcare professional before you order Valtrex online.