My Husband Has Advanced Stage Cholangiocarcinoma. He Is On A

My husband has advanced stage cholangiocarcinoma. He is on a Fentanyl patch 25mcg. Yesterday he had 6 liters of fluid removed due to his ascites. He was complaining of severe constipation this morning, so I suggested he take an Amitiza capsule to see if it would help. He is more miserable than before. Nausea, feels like he could vomit but has not, still constipated....did I make an error in judgment?