Theophylline ER 300 mg typically means an extended-release theophylline tablet containing 300 mg of theophylline per tablet. It’s a prescription bronchodilator with a narrow therapeutic index, so dosing is individualized and usually monitored with blood levels.
Here’s some general info:
- What it’s used for: Help open airways in asthma or COPD. It’s less commonly used now as first-line therapy because it can interact with many drugs and foods.
- How it’s taken: The “ER” (extended-release) formulation is designed to release the drug slowly. Dosing is usually once or twice daily, for example 300 mg every 12 hours or 600 mg once daily, depending on the product and your doctor’s plan. Always follow the exact instructions on your prescription.
- Monitoring: Blood levels are often checked (therapeutic range about 5–15 ng/mL, though exact targets can vary by condition and guidelines). Levels can be affected by smoking, age, liver function, and interactions with other medicines.
- Common side effects: Nausea, vomiting, upset stomach, headaches, tremor, jitteriness, sleep problems, or fast/irregular heartbeat. Higher levels can cause serious issues like seizures or arrhythmias.
- Important interactions and cautions:
- Many antibiotics (e.g., ciprofloxacin, erythromycin, clarithromycin) and antifungals (e.g., ketoconazole) can raise theophylline levels.
- Cimetidine, certain other medicines, and caffeine can also increase effects.
- Smoking can lower theophylline levels.
- Alcohol and liver disease can affect metabolism.
- Do not crush or chew ER tablets; swallow whole unless your clinician says otherwise.
If you want, tell me:
- Are you asking what the 300 mg means, how to dose it, or about specific side effects or drug interactions?
- Are you taking any other medicines (prescription, OTC, or supplements) or have any health conditions (like liver or kidney issues, smoking status)?
I can tailor the information to your situation.