Final answer:
The nurse should monitor the liver function tests (LFTs) which include the aspartate aminotransferase (AST).
Step-by-step explanation:
The nurse should monitor the liver function tests (LFTs) which include the aspartate aminotransferase (AST) or formerly SGOT. Gemfibrozil (Lopid) is known to affect liver function, so monitoring liver enzymes like AST is crucial to ensure the medication is not causing any liver damage or dysfunction.