Which antibiotic should not be given to a patient taking theophylline?

Erythromycin is the antibiotic that should not be given to a patient taking theophylline due to its potential to significantly increase the levels of theophylline in the blood. Erythromycin is a macrolide antibiotic that is known to inhibit the metabolism of theophylline in the liver, specifically through inhibition of the cytochrome P450 enzyme system. This interaction can lead to elevated theophylline levels, increasing the risk of toxicity and associated side effects such as nausea, vomiting, seizures, or cardiac arrhythmias.

In contrast, the other antibiotics listed, such as amoxicillin, clindamycin, and cefadroxil, do not have a significant interaction with theophylline metabolism and are better choices for patients receiving this medication. Therefore, when managing patients who are on theophylline, it is crucial for clinicians to avoid prescriptions of erythromycin to prevent adverse effects stemming from increased theophylline levels.