Bronchodilators - Theophylline

Question 1

Theophylline - classification

Answer 1

Methylxantine drug.

Question 2

Methylxantine drugs

Answer 2

Theophylline
Caffeine
Theobromine

Question 3

Theophylline - effects

Answer 3

Bronchodilation
CNS stimulation
Diuresis
Immunosuppressant
Antiinflammatory

Question 4

Theophylline - MOA

Answer 4

Nonspecific inhibition of phosphodiesterase isoenzymes in bronchial smooth muscle and inflammatory cells. Increases cAMP.
Blockade of adenosine receptors.
Inhibition of Ca influx.
Enhancement of catecholamine secretion.
Impairs release of cationic basic protein and eosinophil-derived neurotoxin.

Question 5

Theophylline - adm

Answer 5

Orally

Question 6

Theophylline - interactions

Answer 6

Metabolized by CYP1A2.
Inducers: cigarette smoke.
Inhibitors: Cimetidine, erythromycin (significant if theophylline is in the high therapeutic range)
Others that increase theophylline levels: Fluoroquinolones, isoniazid, verapamil.

Question 7

Theophylline - duration of action

Answer 7

Normal adults: 8 hours.

Smoking adults and children 1-9 years: 4.5 hours.

Question 8

Important consideration during treatment with theophylline

Answer 8

Narrow margin of safety - monitor levels.

Question 9

Theophylline - indications

Answer 9

COPD (when β2-agonist or muscarinic antagonists are not enough).
Asthma (if other drugs are not enough).
Recurrent neonatal apnea.
Obstructive sleep apnea (may reduce sleep bec of CNS stimulation, tho)

Question 10

Theophylline - beneficial effects in respiratory disorders

Answer 10

Reduced dyspnea and fatigue
Increased diaphragmatic contractility and exercise performance.
Increase central respiratory drive.
Reduced pulmonary artery pressure and vascular resistance. Increased ventricular ejection fractions.
Increased mucociliary clearance and airway inflammation

Question 11

Caffeine - indications

Answer 11

The reason I get up every morning.

Recurrent apnea in premature infants.

Question 12

Methylxantine drugs - MOA in treatment of recurrent neonatal apnea

Answer 12

Block adenosine receptors. Increases sensitivity of respiratory centers to carbon dioxide.

Question 13

Theophylline - adverse effects

Answer 13

GI distress (less when adm with food/antacids/full glass of fluids).
Headache, anxiety, restlessness, insomnia, dizziness, seizures.
Hypotension, bradycardia, premature ventricular contractions, tachycardia.

Question 14

When do serious adverse effects of theophylline occur?

Answer 14

Seizures and serious arrhythmias occur at high serum concentrations (above the safe limit).