I. Physiology and pharmacology

  1. A methylxanthine; increases release of catecholamines
  2. 1 cup of coffee typically has 150-300mg of caffeine
  3. 1 cup of caffeinated soda typically has 50-90mg of caffeine
  4. High-caffeine "energy drinks" may contain 9-33mg of caffeine per fluid ounce

II. Effect on various medical conditions

  1. Conditions that can be exacerbated by caffeine
    1. Gastroesophageal Reflux
    2. Reduced fetal growth in pregnant women
  2. Conditions that may be prevented or ameliorated by caffeine
    1. Type 2 diabetes mellitus

III. Therapeutic uses

  1. Treatment of Headache

IV. Clinical features of caffeine intoxication-Generally resolve within 4-6h of last consumption

  1. Tachycardia
  2. Electrolyte disturbances, particularly hypokalemia
  3. Restlessness and insomnia
  4. Facial flushing
  5. Diuresis
  6. Nausea, vomiting, abdominal pain
  7. Muscle fasciculation
  8. Sinus tachycardia; occasionally supraventricular tachycardia
  9. Hyperglycemia
  10. Seizures (in extreme cases)

V. Caffeine withdrawal

  1. Symptoms develop 12-24h after last use; peak 20-48h; may persist up to 1wk
  2. Headache, fatigue, poor concentration, muscle stiffness

(Sources include Core Content Review of Family Medicine, 2012)