| Item |
Information |
|
Drug Groups
|
approved |
|
Description
|
A methyl xanthine derivative from tea with diuretic, smooth muscle relaxant, bronchial dilation, cardiac and central nervous system stimulant activities. Theophylline inhibits the 3',5'-cyclic nucleotide phosphodiesterase that degrades cyclic AMP thus potentiates the actions of agents that act through adenylate cyclase and cyclic AMP. [PubChem] |
| Indication |
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. |
| Pharmacology |
Theophylline, an xanthine derivative chemically similar to caffeine and theobromine, is used to treat asthma and bronchospasm. Theophylline has two distinct actions in the airways of patients with reversible (asthmatic) obstruction; smooth muscle relaxation (i.e., bronchodilation) and suppression of the response of the airways to stimuli (i.e., non-bronchodilator prophylactic effects). |
| Toxicity |
Symptoms of overdose include seizures, arrhythmias, and GI effects. |
| Affected Organisms |
| • |
Humans and other mammals |
|
| Biotransformation |
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. |
| Absorption |
Theophylline is rapidly and completely absorbed after oral administration in solution or immediate-release solid oral dosage form. |
| Half Life |
8 hours |
| Protein Binding |
40%, primarily to albumin. |
| Elimination |
Theophylline does not undergo any appreciable pre-systemic elimination, distributes freely into fat-free tissues and is extensively metabolized in the liver. Renal excretion of unchanged theophylline in neonates amounts to about 50% of the dose, compared to about 10% in children older than three months and in adults. |
| Distribution |
* 0.3 to 0.7 L/kg |
| Clearance |
* 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] |
| External Links |
|