Nausea, vomiting and indigestion are the most commonly reported side effects at the initiation of therapy. These effects are usually transient and rarely require discontinuation of therapy. Diarrhea, abdominal cramps and constipation have also been reported. Anorexia with some weight loss and increased appetite with some weight gain have also been observed. Sedative effects have been noted in patients receiving valproic acid alone, but are found most often in patients on combination therapy.
Sedation usually disappears upon reduction of other antiepileptic medication.
Rare cases of coma have been reported in patients receiving valproic acid alone or in conjunction with phenobarbital. Transient increases in hair loss have been observed. Skin rash and petechiae have rarely been noted. There have been reports of irregular menses and secondary amenorrhea in patients receiving valproic acid. Emotional upset, depression, psychosis, aggression, hyperactivity and behavioural deterioration have been reported.