1294
A 7-year-old boy developed a severe unilateral grand mal seizure at the age of 5 years (phenobarbitone therapy); 1.5 years later valproate (2-propylpentanoic acid, VPA) was added to the therapy.
 potential therapeutic event: therapy.
Please tell me event type and its trigger word from given type options. Output format is "type: trigger".  Option: adverse event, potential therapeutic event 
Text: {0} 
Answer:
 potential therapeutic event: therapy.