Along with its needing effects, a drug may cause some unwanted effects. Although not all of these side effects may occur, if they do they may need medical attention.
Check with your family doctor as soon as possible if the following side effect occurs:
Less common
Painful menstruation, including abdominal cramps, diarrhea, or nausea
Rare
Black, tarry stools; chest pain; chills; cough; decreased frequency/output of urine; fever; flu-like symptoms; headache; lower back/side pain; reduced mental alertness; shortness of breath; unusual tiredness; yellow eyes or skinFrequency not determined
Back, leg or stomach pains; changes in behavior, especially in interactions with other people; difficulty breathing or swallowing; fast, pounding, or irregular heartbeat; high blood pressure; itching; lightheadedness when getting up from a lying or sitting position; redness of skin; seeing, hearing, or feeling things that are not there; skin rash; swelling or puffiness of face, hands, legs, or feet; wheezingSymptoms of overdose with intravenous acyclovir
Note:Because the information on valacyclovir overdose is limited, information on intravenous acyclovir overdose is provided. In the body, valacyclovir is converted into acyclovir.
Anxiety; convulsions - seizures; decrease in urine output; decreased frequency of urination; dry mouth; hallucinations - seeing, hearing, or feeling things that are not there; irritability; loss of consciousness; lower back/side pain; nervousness; restlessnessMore common side effects may occur that usually do not need medical attention. These side effects may go away during treat as your body adjusts to the drug. However, check with your family doctor if any of these side effects continue or are bothersome:
More common
Headache; nausea
Less common
Constipation; diarrhea; dizziness; joint pain; loss of appetite; stomach pain; unusual tiredness or weakness; vomiting
Frequency not determined
Anxiety; dry mouth; irritability; mood or mental changes; nervousness; restlessnessMore common side effects not listed above may also occur in some diseaseds. If you notice any other problems, check with your family doctor.