If any of the following side effects occur, stop taking Valtrex immediately and contact a doctor for these may be signs of a severe allergic reaction (anaphylaxis):

• Swelling of the face, mouth, throat, or neck, causing trouble breathing
• Severe itchy skin rash and reddening of the skin
• Lowering of blood pressure that may lead to collapse

The most common side effects may include:

• Headache 
• Nausea 
• Dizziness 
• Diarrhea
• Vomiting
• Skin rash 
• Itchy skin
• Reddening of the skin after sun exposure (photosensitivity)

Not all side effects are listed here. For further information regarding potential side effects, refer to the manufacturer’s product insert with this medication.

Consult a doctor or healthcare provider before taking any medication.

Valtrex is indicated for the treatment of viral infections caused by the following viruses: 

• Herpes simplex
• Varicella zoster
• Cytomegalovirus

These viruses may appear in different forms of infection and can be treated with Valtrex at the first sign of outbreak:

• Infection of the eye in adults with a weakened immune system (ophthalmic zoster)
• Shingles in adults
• Herpes infection of the skin, genitals, or eyes
• Recurrent herpes infections
• Cytomegalovirus infection after organ transplant

Valtrex may be used as a long-term treatment to prevent recurring infections or as a short-term treatment as soon as symptoms appear.