Aciclovir Medications

Aciclovir Info

Understanding Aciclovir

Aciclovir is an antiviral medicine that belongs to the nucleoside analogue class. It works by stopping certain viruses from copying themselves, which helps the body control the infection. In Hong Kong, aciclovir appears in several brands and forms, including tablets, capsules, creams and ointments.

Medications with Aciclovir

In the local market you will find aciclovir in both generic and branded products. Common options include:

• Zovirax® tablets - usually 200 mg or 400 mg strengths, taken by mouth.
• Zovirax® cream - a 5 % topical preparation applied to the skin.
• Zovirax® ointment - a similar concentration for use on sensitive areas.
• Generic aciclovir tablets - sold under the name “Aciclovir” in pharmacies, matching the same strengths as the brand.

These formulations are regulated by Hong Kong’s Pharmacy and Poisons Board and are available by prescription for systemic use, while the topical creams and ointments may be obtained over the counter for mild cases.

What Does Aciclovir Treat?

Aciclovir is used for a range of viral infections caused by the herpes family of viruses. Typical conditions include:

• Cold sores (herpes simplex labialis) - small blisters around the mouth that appear during a flare-up.
• Genital herpes (herpes simplex genitalis) - painful sores in the genital area that may recur.
• Shingles (herpes zoster) - a painful rash that follows a nerve pathway, usually on one side of the body.
• Severe primary herpes infections - such as a first-time oral or genital outbreak that may need stronger treatment.

The drug helps to shorten the duration of symptoms, reduce the severity of lesions, and may lower the chance of the virus spreading to others.

How Aciclovir Works

Aciclovir mimics a building block that viruses need to make new DNA. When the virus tries to use aciclovir, it becomes trapped and can no longer multiply. This blockage slows the infection, giving the immune system a better chance to clear the virus. Effects can be seen within a day or two, although full improvement may take several days depending on the infection.

Safety Information

Common Side Effects

• Mild stomach upset or nausea.
• Headache or feeling light-headed.
• Minor skin irritation where a cream or ointment is applied.

These reactions are usually short-lived and resolve without medical treatment.

Serious Reactions

• Allergic signs such as swelling of the face, lips or throat, or a rash that spreads quickly.
• Severe skin reactions, including blistering or peeling.
• Unusual changes in urine colour or amount.

If any of these occur, seek urgent medical help.

Who Should Be Cautious

• Pregnant or breastfeeding individuals should discuss the use of systemic aciclovir with a health professional, as safety data are limited.
• People with kidney problems may need special attention because aciclovir is cleared through the kidneys.
• Individuals who have experienced a hypersensitivity reaction to aciclovir or any of its ingredients should avoid it.

Interaction Awareness

• Certain medicines that affect kidney function, such as some non-steroidal anti-inflammatory drugs, can increase aciclovir levels.
• Alcohol does not directly interact with aciclovir, but excessive drinking can worsen dehydration and kidney strain.
• Topical aciclovir can be used together with other skin preparations, but avoid mixing with irritant products that may increase local discomfort.

For a full list of possible interactions, refer to the specific product’s information sheet.

What to Know Before Using

Store tablets and capsules in a cool, dry place, away from direct sunlight. Creams and ointments should be kept at room temperature and the cap tightened tightly after each use. Treatment length varies: short courses are typical for cold sores, while shingles or genital herpes may require a longer regimen. Always follow the directions that come with your particular medication, as strengths and dosing schedules differ between products.

Key Terms

Antiviral: A drug that stops viruses from growing or spreading.

Herpes simplex virus: The virus that causes cold sores and genital herpes.

Herpes zoster: The virus that leads to shingles, usually re-activating later in life.

Topical: Applied directly to the skin or mucous membranes.

Systemic: Taken by mouth or injection, affecting the whole body.

Information Disclaimer

This article provides general educational information about aciclovir as an active substance used in various medicines. Its purpose is to help patients better understand the ingredient and the conditions it is used to treat. It is not a substitute for professional medical advice or for the specific instructions provided with individual products. Medicines containing aciclovir may differ in formulation, strength, and directions for use. Always consult the labeling of your particular medication and follow your healthcare provider’s guidance for complete information on proper use, dosage, and safety.