Product Information

Registration Status: Active

THEOLIN SR TABLET 250mg is approved to be sold in Singapore with effective from 1989-09-06. It is marketed by BEACONS PHARMACEUTICALS PTE LTD, with the registration number of SIN03147P.

This product contains Theophylline 250mg in the form of TABLET, FILM-COATED. It is approved for ORAL use.

This product is manufactured by BEACONS PHARMACEUTICALS PTE LTD in SINGAPORE.

It is a Prescription Only Medicine that can only be obtained from a doctor or a dentist, or a pharmacist with a prescription from a Singapore-registered doctor or dentist.



A methylxanthine derivative from tea with diuretic, smooth muscle relaxant, bronchial dilation, cardiac and central nervous system stimulant activities. Mechanistically, theophylline acts as a phosphodiesterase inhibitor, adenosine receptor blocker, and histone deacetylase activator. Theophylline is marketed under several brand names such as Uniphyl and Theochron, and it is indicated mainly for asthma, bronchospasm, and COPD.


For the treatment of the symptoms and reversible airflow obstruction associated with chronic asthma and other chronic lung diseases, such as emphysema and chronic bronchitis.

Mechanism of Action

Theophylline relaxes the smooth muscle of the bronchial airways and pulmonary blood vessels and reduces airway responsiveness to histamine, methacholine, adenosine, and allergen. Theophylline competitively inhibits type III and type IV phosphodiesterase (PDE), the enzyme responsible for breaking down cyclic AMP in smooth muscle cells, possibly resulting in bronchodilation. Theophylline also binds to the adenosine A2B receptor and blocks adenosine mediated bronchoconstriction. In inflammatory states, theophylline activates histone deacetylase to prevent transcription of inflammatory genes that require the acetylation of histones for transcription to begin.


Theophylline is rapidly and completely absorbed after oral administration in solution or immediate-release solid oral dosage form.
* 0.3 to 0.7 L/kg
Hepatic. Biotransformation takes place through demethylation to 1-methylxanthine and 3-methylxanthine and hydroxylation to 1,3-dimethyluric acid. 1-methylxanthine is further hydroxylated, by xanthine oxidase, to 1-methyluric acid. About 6% of a theophylline dose is N-methylated to caffeine. Caffeine and 3-methylxanthine are the only theophylline metabolites with pharmacologic activity.


* 0.29 mL/kg/min [Premature neonates, postnatal age 3-15 days] * 0.64 mL/kg/min [Premature neonates, postnatal age 25-57 days] * 1.7 mL/kg/min [Children 1-4 years] * 1.6 mL/kg/min [Children 4-12 years] * 0.9 mL/kg/min [Children 13-15 years] * 1.4 mL/kg/min [Children 16-17 years] * 0.65 mL/kg/min [Adults (16-60 years), otherwise healthy non-smoking asthmatics] * 0.41 mL/kg/min [Elderly (>60 years), non-smokers with normal cardiac, liver, and renal function] * 0.33 mL/kg/min [Acute pulmonary edema] * 0.54 mL/kg/min [COPD >60 years, stable, non-smoker >1 year] * 0.48 mL/kg/min [COPD with cor pulmonale] * 1.25 mL/kg/min [Cystic fibrosis (14-28 years)] * 0.31 mL/kg/min [Liver disease cirrhosis] * 0.35 mL/kg/min [acute hepatitis] * 0.65 mL/kg/min [cholestasis] * 0.47 mL/kg/min [Sepsis with multi-organ failure] * 0.38 mL/kg/min [hypothyroid] * 0.8 mL/kg/min [hyperthyroid]


Symptoms of overdose include seizures, arrhythmias, and GI effects.

Active Ingredient/Synonyms

1,3-dimethyl-7H-purine-2,6-dione | 1,3-dimethylxanthine | Theophyllin | Theophylline anhydrous | Theophylline, anhydrous | Theophylline |

Source of information: Drugbank (External Link). Last updated on: 3rd July 18. *Trade Name used in the content below may not be the same as the HSA-registered product.


  1. Health Science Authority of Singapore - Reclassified POM
  2. Drugbank