Pharmacology Xanthines

1
Pharmacology - Xanthines

• By Jim Clarke

2
Why Use Xanthines?

• Used as bronchodilators for asthma and COPD
  patients
• Not as widely used in the 90s 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 5 and
  20 mcg/ml
• Levels gt 30 mcg/ml can cause cardiac arrhythmias
• Levels gt 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 its use in treatment
  of exacerbations of COPD
• Can cause severe gastric upset

11
End of Presentation