Antiviral drugs are medicines that cure or control virus infections. Antiviral family has several different drugs and each is used for specific of kind of viral infection. For example, acyclovir (Zovirax) is used to treat chickenpox, shingles, and the symptoms of herpes virus infections of the genitals, lips, mouth, skin, and brain. The medicine however, does not cure the infections, but it relieves the discomfort and speeds healing of sores, when they are present. Similarly, valacyclovir (Valtrex) and famciclovir (Famvir) can also be used to relieve the symptoms of shingles.
Other types of antiviral drugs, such as amantadine (Symmetrel) and rimantadine (Flumadine) are used to prevent or treat certain kinds of influenza (flu). They are given either alone or in combination with flu shots. These drugs will not work for common colds, other types of flu, or other virus infections, however.
Some people feel dizzy, confused, or lightheaded when using these drugs. The medicine may also cause blurred vision and problems with concentration. For these reasons, anyone who takes these drugs should not drive, use machines or do anything else that might be dangerous until they have found out how the drugs affect them.
Drinking alcoholic beverages while taking certain antiviral drugs may increase the chance of side effects. Anyone who takes these drugs should check with a physician before drinking alcohol or taking medicines that contain alcohol.
When taking an antiviral medicine for chickenpox, shingles, or herpes infection, start taking the medicine as soon as possible after the symptoms appear. Patients who are taking an antiviral drug for herpes should keep in mind that the medicine will not prevent them from spreading the infection to other people. They must still take these precautions to avoid passing the virus through sexual contact:
- Avoid any sexual activity if either partner has sores or other symptoms of herpes
- Use either a male or female condom at other times.
The most common minor side effects are diarrhea, nausea or vomiting, dizziness, lightheadedness, headache, sleep problems, concentration problems, and irritability or nervousness. These problems usually go away as the body adjusts to the drug and do not require medical treatment unless they do persist or they interfere with normal activities.
More serious side effects of antiviral drugs include:
- Pain, swelling, or redness at the place where the medicine was injected
- Severe pain in the stomach or abdomen
- Problems urinating
- Increased thirst
- Loss of appetite
Anti-viral drugs may interact with a number of other medicines. When this happens, the effects of one or both of the drugs may change or the risk of side effects may be greater. Anyone who takes antiviral drugs should let the physician know all other medicines he or she is taking. Antiviral drugs may interact with some of the following drugs
- Pain medicines such as Excedrin that contain acetaminophen combined with aspirin or other salicylates
- Other medicines for pain or inflammation (except narcotics)
- Cimetidine (Tagamet)
- Medicine for asthma, allergies, hay fever, or colds
- Anticancer drugs
The list above does not include all the drugs that may interact with Anti-viral drugs. One has to be make sure to check with a physician or pharmacist before combining Anti-viral drugs with any other (over-the-counter) medicine.