1. Pharmacology - Xanthines
By Jim Clarke

2. Why Use Xanthines?
Used as bronchodilators for asthma and COPD patients
Not as widely used in the 90’s as has been the case in the past
Now considered to be second or third-line drugs in treatment of asthma & COPD

3. Types of Xanthines Caffeine - limited bronchodilating effect
Theobromine - found in cocoa
Theophylline preparations
has been widely used as a bronchodilator
years ago used as a dieuretic

4. Physiological Effects of Xanthines
Central Nervous System stimulant
Stimulates cardiac muscle
Increases diuresis
Relaxes bronchial, vascular and uterine smooth muslce
Peripheral & coronary artery vasodilation
Cerebral vasoconstriction

5. How Theophylline Bronchodilates
Currently there are 3 theories;
Inhibition of Phosphodiestarase
Antagonism of Adenosine
Increases production of catecholamines
Theophylline preparations also may increase breathing muscle strength

6. How Theophylline is Given
I.V. Preparations -
Aminophylline
P.O. Preparations
Bronkodyl
Elixophylline
Slo-Phylline
Theo-Dur
Choledyl

7. Side Effects Nausea, vomiting, anorexia, diarrhea
Cardiac arrhythmias, hypotension
Tachypnea
Headache, restlessness, insomnia, anxiety
Seizures

8. Monitoring Blood Levels
Theophylline levels should be between and 20 mcg/ml
Levels > 30 mcg/ml can cause cardiac arrhythmias
Levels > 40 mcg/ml can cause seizures

9. Agents That Effect Theophylline Blood Levels
Decrease blood levels
Beta agonists
Cigarette smoking
Increase blood levels
Cirrhossis & hepatitis
Corticosteroids
Beta-blockers

10. Clinical Uses Not recommended as a first-line drug in asthma treatment
Only recommended in asthma when the more typical agents have not worked
ATS guidelines DO recommend it’s use in treatment of exacerbations of COPD
Can cause severe gastric upset

11. End of Presentation