Antiviral Medications
Antiviral medications target specific viruses by interfering with their replication cycle. They are used for herpes simplex, varicella-zoster, influenza, HIV, hepatitis B and C, and emerging viral infections. Treatment is led by a clinician.
Overview
Antivirals are a heterogeneous group of medications that act selectively on viral replication, including viral entry, nucleic acid synthesis, protein processing and viral release. They differ from antibiotics, which act on bacteria, and require precise diagnosis of the causative virus. According to international guidelines, antivirals are prescribed for documented or strongly suspected viral infections such as herpes simplex, varicella-zoster, influenza, respiratory syncytial virus, HIV and viral hepatitis. Misuse contributes to viral resistance.
Common treatments
Pharmacological options include nucleoside analogues such as acyclovir and valacyclovir for herpes infections; neuraminidase inhibitors such as oseltamivir for influenza; combination antiretroviral therapy for HIV; direct-acting antivirals for hepatitis C; nucleotide analogues for hepatitis B; and broad-spectrum agents emerging from research into respiratory viruses. Antivirals are most effective when started early in the course of acute infection.
When to consult
Severe or unusual viral symptoms, immunocompromise, suspected new or recurrent herpes lesions, exposure to influenza in high-risk groups and confirmed positive testing for chronic viral infections all require medical evaluation. According to clinical guidelines, the first consultation should establish the specific virus, immune status and any contraindications. Self-medication with online products is discouraged because it bypasses this assessment and may worsen resistance.
Medications
Frequently asked questions
Can antivirals cure viral infections? ▾
Some antivirals can clear specific infections, such as direct-acting antivirals for hepatitis C, while others suppress replication without elimination, such as antiretroviral therapy for HIV or aciclovir for recurrent herpes. According to international guidelines, the goal of antiviral therapy depends on the virus: cure for hepatitis C, sustained viral suppression for HIV, faster healing of acute episodes for herpes, and reduction of complications for influenza.
How is acyclovir different from valacyclovir? ▾
Both are nucleoside analogues active against herpes simplex and varicella-zoster viruses. Valacyclovir is a prodrug of acyclovir with much higher oral bioavailability, allowing less frequent dosing (typically two or three times daily) compared with five times daily for oral acyclovir. Clinical efficacy is comparable at equivalent acyclovir exposures. According to clinical guidelines, valacyclovir is preferred when adherence is a concern, with the choice made by the prescriber.
When is oseltamivir recommended for influenza? ▾
According to international guidelines, oseltamivir is recommended for adults and children with confirmed or strongly suspected influenza who are at high risk of complications, who require hospitalisation, or who have severe progressive disease. Treatment is most effective when started within 48 hours of symptom onset. Routine use in low-risk patients with mild influenza is more controversial and should be discussed with the prescriber.
Can antivirals be used preventively? ▾
Yes, in selected situations. Antivirals are used as pre-exposure prophylaxis for HIV in high-risk individuals, as suppressive therapy for recurrent genital herpes, and post-exposure for influenza in high-risk contacts during outbreaks. According to clinical guidelines, prophylaxis is individualised based on the specific virus, exposure risk and patient factors, and should be decided after evaluation by a clinician.
Is online purchase of antivirals safe? ▾
Buying antivirals from unverified online sources is associated with documented risks: counterfeit tablets, sub-therapeutic doses contributing to resistance, and absence of medical review. This is particularly important for chronic antiviral therapy in HIV and viral hepatitis, where treatment failure can be life-threatening. Regulatory bodies recommend purchasing only from licensed pharmacies and only after evaluation by a qualified clinician.
The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.