Valtrex and Zovirax are antiviral medications commonly used to treat herpes infections such as cold sores, genital herpes, and shingles by stopping viral replication and reducing symptoms and transmission. Antiviral therapy is most effective when started early, particularly for shingles and flu, to reduce pain, complications, and duration of illness. These medications are widely used for both acute and long-term suppressive therapy in herpes simplex and herpes zoster, with minimal side effects and proven safety.