Final answer:
The nurse should instruct the client to swallow the capsules whole to ensure proper absorption in the small intestine for the treatment of a duodenal ulcer.
Step-by-step explanation:
The nurse should instruct the client to swallow the capsules whole. Omeprazole is a proton pump inhibitor that works best when absorbed in the small intestine rather than in the stomach, which is why it should not be taken with food or dissolved. It's often recommended to take omeprazole before eating, usually in the morning, to effectively decrease the amount of acid made in the stomach. This aids in healing the duodenal ulcer and managing symptoms. However, for specific prescription guidelines including timing, the patient should follow their physician's advice, as directions may vary based on individual medical history and the overall treatment plan.