2154
We conclude that the presence of this metabolic defect combined with topical 5-FU ( a drug demonstrating a narrow therapeutic index ) results in the unusual presentation of life - threatening toxicity after treatment with a topical drug .
 adverse effect: life - threatening toxicity, 5-FU
Given options, please tell me the relationships of all the listed entity pairs.Output format is "relation1: word1, word2; relation2: word3, word4". 
Option: adverse effect 
Text: {0} 
 Entity Pairs:  life - threatening toxicity, 5-FU 
Answer:
 adverse effect: life - threatening toxicity, 5-FU