Pharm

Theophylline

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Theophylline, Methylxanthine, Aminophylline

  • Precautions
  1. Theophylline is listed here for completeness, not for recommended use
  2. In the developed world, Theophylline and its adverse effects are largely supplanted by better agents
    1. Limited roles may be found in refractory cases under specialty care, and in underdeveloped world regions
  • Indications
  1. Limited utility where standard of care Asthma Management is available
  • Preparations
  • Methylxanthines
  1. Aminophylline
  2. Caffeine
  3. Pentoxifylline (Trental)
  4. Theophylline
  • Mechanism
  1. Xanthines are isolated from plants Camellia sinensis and Coffea arabica
  2. Activity: Xanthines and Methylxanthines in general
    1. Xanthines inhibit phosphodiesterase and prostaglandin production
    2. Moderate cellular calcium
    3. Block Adenosine
  3. Effects: Theophylline
    1. Bronchial smooth muscle relaxation (high doses of Theophylline)
    2. Peripheral vasodilation (not central)
    3. CNS and cardiac stimulant
    4. Diuretic
    5. Anti-inflammatory (at low doses of Theophylline)
  • Dosing
  1. Theophylline 150 to 300 mg twice daily
  • Adverse Effects
  1. Serum Theophylline Level <20 mg/L
    1. Headache
    2. Insomnia
    3. Nausea
    4. Vomiting
  2. Serum Theophylline Level >20 mg/L
    1. Arrhythmias
    2. Seizures
  • Drug Interactions
  1. Agents that increase Theophylline serum concentrations
    1. Alcohol
    2. Ciprofloxacin
    3. Diltiazem
    4. Erythromycin
    5. Oral Contraceptives
    6. Propranolol (very strong effect, doubles the Theophylline concentration)
    7. Verapamil
  2. Agents that decrease Theophylline serum concentrations
    1. Phenytoin (Dilantin)