> Western Medicines > Theophylline


Chinese name:

What is Theophylline for?

Theophylline belongs to a class of medications called phosphodiesterase (PDE) inhibitors. It is a bronchodilator which can relax the muscles of the airways and open up the airways in the lungs making breathing easier. 


It is most commonly used to treat asthma, chronic obstructive pulmonary disease (COPD), and bronchoconstriction by relieving symptoms of shortness of breath like breathlessness, coughing and wheezing.

How to use it?

Theophylline is taken by mouth in the form of syrup, conventional tablet or sustained-release tablets / capsules. 


If you are taking the sustained-release (SR tablets/capsules, you should swallow whole and do not crush or chew them. 


The doses of Theophylline vary with different brands. The usual adult doses of Theophylline are 175-500 mg every 12 hours. Consult your doctor or pharmacist for more details before using Theophylline.


Long-term treatment with Theophylline usually requires regular monitoring of your Theophylline blood levels.

What are the side effects of Theophylline?

Common side effects of Theophylline include nausea, vomiting, headache, insomnia, tremor, restlessness, and irregular heartbeats.

Who should not take Theophylline?

  • People who are allergic to Theophylline or any component of the formulation.

Pharmacist Tips:

  • Do not break, chew or open sustained-release preparations. Swallow whole with water.

Common dosing schedule: 

  • You can take Theophylline with or without food. However, keep it consistent.

This schedule is for reference only, adjustments may be made according to individual needs.

Some common medications Theophylline may interact with:

Theophylline can interact with a number of other medications, please notify your doctor or pharmacist of other concurrent medications you are taking, dosage adjustments might be needed.

Where to buy Theophylline in Hong Kong?

In Hong Kong, Theophylline is pharmacy only medicines and can be purchased without a prescription in a pharmacy by speaking with the pharmacist. It can also be obtained from doctors. To find a pharmacy near you, refer to the list of pharmacies (“Authorized Sellers of Poisons”) from the Hong Kong Department of Health.


For more information about drug names and ingredients, you can visit Hong Kong’s Drug Office at https://www.drugoffice.gov.hk

Need more information?

For detailed information about the use of Theophylline in children, pregnancy and breastfeeding, and for questions about drug interactions, please check with your pharmacist or doctor.

Disclaimer: our goal is to provide you with the most relevant drug information and common dosage for Hong Kong. This information does not constitute medical advice. For specific treatment recommendations and advice, always discuss with your doctor or pharmacist, and follow the instructions included with your specific medicine.

Brands in Hong Kong
Available dosage
  • 50mg / 100mg / 250mg (Capsules)
  • 80mg/15ml (Syrup)
  • 125mg / 200mg / 250mg / 300mg (Tablets)
Drug class
Sub class
Phosphodiesterase Inhibitors
Other drugs in same class
Used for: Prevention of thromboembolic events
Chinese name:
Used for: Erectile dysfunction, Pulmonary arterial hypertension, Benign Prostatic Hyperplasia (BPH)
Chinese name:
Used for: Prevention of thromboembolic events
Chinese name: