2519
Recent studies have shown that under experimental conditions ferrous sulfate may reduce the gastrointestinal absorption of orally administered levothyroxine sodium in patients with primary hypothyroidism.
 adverse event: reduce 
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:
 adverse event: reduce 