CRNI Practice Exam Prep: Study Guide & Practice Questions

Theophylline is a widely used medication for respiratory diseases such as asthma and chronic obstructive pulmonary disease (COPD). It has a narrow therapeutic index, meaning that the difference between an effective dose and a potentially harmful dose is small. Certain classes of drugs can interact with Theophylline, either increasing or decreasing its levels in the body.

Antibiotics, particularly those in the fluoroquinolone class and certain macrolides, can inhibit the metabolism of Theophylline in the liver. This leads to increased plasma concentrations of Theophylline, potentially resulting in toxicity or adverse effects. The interaction happens because these antibiotics inhibit specific enzymes in the cytochrome P450 system, which is responsible for metabolizing Theophylline.

In contrast, antifungals can also impact Theophylline levels, but not as commonly as antibiotics. Antihistamines and analgesics do not have a significant interaction with Theophylline metabolism. This illustrates the importance of being aware of drug interactions when prescribing or administering Theophylline, especially in patients who may be on concomitant antibiotic therapy. Understanding these interactions helps healthcare providers optimize treatment plans to minimize the risk of toxicity and ensure effective management of respiratory conditions.