| Aminophylline Pharmacology |
| Aminophylline |
| About Aminophylline |
| Theophylline Ethylenediamine, Bronchodilator. |
| Mechanism of Action of Aminophylline |
| Aminophylline is a complex of Theophylline and Ethylenediamine. Aminophylline is converted to Theophylline in aqueous solution and this Theophylline exerts therapeutic effect by inhibiting phosphodiesterase enzyme and blocking adenosine receptors. Inhibition of phosphodiesterase enzyme will dilate the bronchial smooth muscle. Inhibition of cyclic nucleotide phosphodiesterase will lead to accumulation of cyclic AMP and cyclic GMP and increases signal transduction through these pathways. Aminophylline relaxes muscles in lungs and chest to allow more air in, decreases the sensitivity of lungs to allergens and other substances that cause inflammation, and increases the contractions of diaphragm to draw more air into the lungs. Aminophylline is used to treat the symptoms of asthma, bronchitis, and emphysema Theophylline is a competitive antagonist at adenosine receptors and produce bronchodilation in asthma patients. |
| Pharmacokinets of Aminophylline |
| Absorption: Aminophylline is absorbed well after oral administration. Distribution: It is distributed to extracellular fluid and all tissues except fatty tissues. Metabolism: It is initially converted to active Theophylline and then to inactive compounds. Excretion: It is excreted mainly in urine. |
| Onset of Action for Aminophylline |
| Oral: 15 – 60 minutes, IV: 15 minutes |
| Duration of Action for Aminophylline |
| N/A |
| Half Life of Aminophylline |
| N/A |
| Side Effects of Aminophylline |
| 1. Nausea 2. Vomiting 3. Diarrhea 4. Abdominal pain 5. Headache 6. Dizziness 7. Insomnia 8. Tremor 9. Anxiety 10. Decreased appetite 11. Weight loss 12. Restlessness 13. Flushing 14. Irritability 15. Nervousness 16. Increased urination 17. Hypotension |
| Contra-indications of Aminophylline |
| 1. Hypersensitivity to Aminophylline and other Xanthine compounds 2. Epilepsy 3. Infection of the rectum or lower colon (rectal suppositories) |
| Special Precautions while taking Aminophylline |
| 1. Hepatic impairment 2. Renal impairment 3. Heart failure 4. Hypertension 5. Chronic obstructive pulmonary diseases (COPD) 6. Hyperthyroidism 7. Diabetes mellitus 8. Peptic ulcer 9. Severe hypoxemia |
| Pregnancy Related Information |
| Use with caution |
| Old Age Related Information |
| Use with caution |
| Breast Feeding Related Information |
| Use with caution |
| Children Related Information |
| Use with caution NEONATES: contraindicated |
| Indications for Aminophylline |
| 1. Bronchospasm, 2. Acute asthma, 3. Respiratory stimulant, |
| Interactions for Aminophylline |
| Benzodiazepines: Sedative effects may be antagonized. Beta agonists: Additive effect. Halothane: Catecholamine induced arrhythmias may occur. Tetracyclines: Theophylline adverse reaction may be enhanced. |
| Typical Dosage for Aminophylline |
| Adult: Oral: 100 – 300 mg 6-8 hours daily should be taken after meals. IV infusion: 5 mg/kg body weight as IV infusion over 20 minutes. Children: IV infusion: 5 mg/kg body weight as IV infusion over 20 minutes |
| Schedule of Aminophylline |
| H |
| Storage Requirements for Aminophylline |
| Store at room temperature. Protect from heat and light. |
| Effects of Missed Dosage of Aminophylline |
| Take the missed dose as soon as noticed and if it is the time for next dose then skip the missed dose. Continue the regular schedule. Do not double the dose. |
| Effects of Overdose of Aminophylline |
| Give supportive measures and symptomatic treatment. Drug can be removed from the body by inducing emesis and the absorption of the drug can be reduced by administration of activated charcoal. Arrhythmia can be treated with Lidocaine and seizure with IV benzodiazepines. |