Medicines & Supplements A to Z > Valaciclovir


Last updated on 25/07/2021.

Overview   |   Dosage   |    Side Effects   |   Precautions  |   Tips  |   Where To Buy  

GENERIC NAME: Valaciclovir


BRAND NAME(S) IN HONG KONG: Valtrex 袪疹易, Valtra, Valajub

DRUG CLASS: Antivirals

SUB CLASS: Guanine nucleoside analogue

USED FOR: Herpes Simplex Virus Infection, Herpes zoster (Shingles)

– 500mg, 1g (tablets)

What is Valaciclovir for?

Shingles is caused by infection of varicella zoster virus (VZV). Patients will feel strong pain on the blisters formed as a group over their bodies. Shingles often takes place in older people who had chickenpox before. It can cause blindness if there are shingles near the eyes. Valaciclovir blocks the virus from replication by inhibiting DNA polymerase of viruses. Therefore, it is used to treat herpes simplex virus infection and shingles.

How to use it?

There are capsules and tablets for oral use. It does not differ much whether you take it with food or not. If GI upset occurs, administer with meals.

Herpes zoster infection
Take 1g 3 times daily for 7 days.
Immunocompromised adult
Take 1g 3 times daily for 7 days or more, continue for 2 days after crusting of lesions. 

Herpes simplex virus, first episode
Take 500mg twice daily for 5 days. Continue if healing incomplete or new lesions form.
Immunocompromised adult
Take 1g twice daily for 10 days.

Herpes simplex virus, recurrence
Take 500mg twice daily for 3-5 days.
Immunocompromised adult
Take 1g twice daily for 5-10 days.

Herpes simplex, suppression
Take 500mg daily in one or two doses. Reassess recurrence per 6-12 months. 

Genital Herpes (reduction of transmission)
Take 500mg daily by the infected partner.

Prophylaxis of cytomegalovirus disease
Adult after organ transplantation
Take 2g 4 times daily for 90 days, start by 72 hours after transplantation.

What are the side effects of Valaciclovir?

Common side effects of Valaciclovir include diarrhea, headache, nausea, vomiting and dizziness.

Who should not take Valaciclovir?

– Pregnant and breastfeeding women
– Patients who are allergic to Valaciclovir and any components in the formulation

Pharmacist Tips:

– Patients with declined liver or kidney function need dose reduction.
– People who are concerned about shingles may seek vaccination or re-vaccination of varicella vaccine.
– People never infected with VZV are more likely to have chickenpox first.

Common dosing schedule:
Take Valaciclovir 3 times daily for 7 days. It does not differ much whether you take it with food or not. If GI upset occurs, administer with meals.

This schedule is for reference only, adjustments may be made according to individual needs.

Some common medications Valaciclovir may interact with:
– Phenylacetic acids, e.g. Diclofenac, Aceclofenac
– Some antiretrovirals, e.g. Adefovir, Cidofovir
– 2-arylpropionic acid derivatives, e.g. Ibuprofen, Ketoprofen
– Cancer drugs, e.g. Imatinib, Cisplatin
– Immunosuppressants, e.g. Methotrexate, Mercaptopurine

Please notify your doctor or pharmacist if you are taking the above medication, dosage adjustments might be needed.

Where to buy Valaciclovir in Hong Kong?

In Hong Kong, Valaciclovir is a prescription only medicine, and requires a prescription from a doctor to be purchased in a pharmacy. It can also be obtained from doctors. To find a pharmacy near you, refer to the list of pharmacies (“Authorized Sellers of Poisons”) from the Hong Kong Department of Health.

For more information about drug names and ingredients, you can visit Hong Kong’s Drug Office at

Need more information?

For detailed information about the use of Valaciclovir in children, pregnancy and breastfeeding, and for questions about drug interactions, please check with your pharmacist or doctor.

Disclaimer: our goal is to provide you with the most relevant drug information and common dosage for Hong Kong. This information does not constitute medical advice. For specific treatment recommendations and advice, always discuss with your doctor or pharmacist, and follow the instructions included with your specific medicine.