What is a primary concern when prescribing theophylline?

The primary concern when prescribing theophylline is the need for regular blood level monitoring. Theophylline is a bronchodilator often used in the management of asthma and chronic obstructive pulmonary disease (COPD). However, it has a narrow therapeutic index, meaning the difference between an effective dose and a toxic dose is small. Therefore, serum theophylline levels must be monitored regularly to ensure they remain within the therapeutic range, generally between 10 to 20 mcg/mL.

Monitoring is critical because elevated levels can lead to adverse effects such as nausea, vomiting, diarrhea, insomnia, and even more serious complications like seizures or arrhythmias. It is also important to consider factors that can affect theophylline levels, such as changes in the patient's condition, drug interactions, and variations in metabolism due to lifestyle factors. Regular monitoring helps to fine-tune dosages and improve safety and efficacy in treatment.

While the other concerns listed, such as potential for abuse, development of tolerance, and renal impairment, are valid considerations in the use of many medications, they are not as critical to the management of treatment with theophylline as the necessity for ongoing blood level monitoring.