Antiviral medication: what they do and how to use them safely

Ever started an antiviral and wondered if you were using it right? Antiviral medicines treat infections caused by viruses, not bacteria. They can stop a virus from making copies of itself, shorten how long you feel sick, and prevent complications when used correctly. This short guide tells you which antivirals treat what, common side effects, and simple tips to keep treatment effective and safe.

Common antiviral drugs and what they're for

Here are the antiviral drugs you’ll see most often and the situations they help with.

Acyclovir, valacyclovir — used for herpes simplex (cold sores, genital herpes) and shingles. These work best when started early in an outbreak.

Oseltamivir — often prescribed for influenza. It helps most when started within 48 hours of symptoms.

Tenofovir, emtricitabine, lamivudine, efavirenz and others — part of HIV treatment. HIV meds are given as combinations to stop resistance and keep the virus suppressed.

Sofosbuvir and similar drugs — used for hepatitis C. Many are taken for a set number of weeks and can cure the infection in most people.

Remdesivir — an antiviral used in hospital settings for certain severe COVID-19 patients. Its use is guided by doctors based on condition and setting.

Practical tips: taking, side effects, and buying safely

Take the full course exactly as prescribed. Stopping early can let the virus rebound and may encourage resistance. If a pill says twice a day, try to keep the same gap between doses every day.

Watch for side effects. Common ones are nausea, headache, and tiredness. Some antivirals can affect kidneys or liver. If you have kidney or liver disease, tell your prescriber — doses may need adjusting and simple blood tests like creatinine or liver enzymes might be requested.

Avoid mixing with unnecessary remedies. Alcohol doesn't usually block antivirals directly, but it can worsen side effects or harm the liver. Also, don’t share your medicine with others or use someone else’s prescription.

Buying online? Use a licensed pharmacy and require a prescription. Avoid offers that sell prescription antivirals without asking for one or that look too-good-to-be-true. Look for clear contact info, a physical address, and verified reviews. When in doubt, call your local pharmacist or doctor first.

If you’re pregnant, breastfeeding, or immunosuppressed, check with your healthcare provider before starting any antiviral. Some are safe and necessary; others need extra caution. Got side effects or questions? Contact your prescriber — small issues can become big if left unchecked.

Antivirals work best when used properly. Pick a trusted source for your meds, follow instructions, and keep your healthcare team in the loop. That’s the shortest path to getting better and staying safer.