Which statement indicates that a client needs further education regarding theophylline use?

The statement indicating that a client needs further education regarding theophylline use is that the client takes cimetidine rather than omeprazole for heartburn. Theophylline is a bronchodilator used mainly for respiratory conditions such as asthma and COPD. It has a narrow therapeutic index, which means that small changes in its concentration can significantly affect its effectiveness and potential for toxicity.

Cimetidine, an H2 receptor antagonist used to treat gastric acid conditions, can interfere with the metabolism of theophylline, increasing the risk of toxicity since it inhibits the liver enzymes (particularly CYP1A2) responsible for metabolizing theophylline. Omeprazole, a proton pump inhibitor, does not have the same significant interaction with theophylline and is generally a safer choice in this context.

Therefore, taking cimetidine instead of omeprazole suggests a lack of understanding about how certain medications can affect theophylline levels in the body and the importance of selecting medications that will not lead to increased toxicity or reduced efficacy. This highlights a need for further education on drug interactions and safe medication practices related to theophylline therapy.