Always take the complete course of treatment, as advised by your doctor even if you feel better. Drink plenty of water while on treatment with Cyclovir 200 mg Tablet. This helps to prevent kidney stone and kidney damage. Inform your doctor if you have ever been diagnosed with kidney or liver problems. A dose of your medicine may need to be adjusted. You should not have sex if you have genital sores or blisters. If you are taking Cyclovir 200 mg Tablet for herpes, you should use barrier methods (condoms) when you're having sex since you can still pass it on to other people, even if you are taking the medication. Inform your doctor if you are pregnant or planning to conceive or breastfeeding.Common side effects include Headache, Nausea, Vomiting, Dizziness, Fatigue, Diarrhoea, Abdominal pain, Skin rash, Fever. The following information is an educational aid only. It is not indicated as medical advice or treatment. Consult your Doctor on safety and effectiveness.