What side effect can be caused by theophylline derivatives?

Theophylline derivatives, commonly used as bronchodilators in the treatment of asthma and COPD, are known to have a variety of side effects due to their mechanism of action, which involves the inhibition of phosphodiesterase and adenosine receptor antagonism. Nervousness is a notable side effect that can occur with theophylline use. This is primarily due to the stimulation of the central nervous system, leading to increased alertness and potentially causing anxiety or nervousness in some patients.

Theophylline's stimulant effects can also lead to increased heart rate and restlessness, contributing to an overall feeling of nervousness. This side effect can be particularly concerning if patients have a pre-existing anxiety disorder or if they are sensitive to stimulants. Thus, the presence of nervousness aligns directly with the pharmacological properties and side effect profile of theophylline derivatives.