Pharm

Doxycycline

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Doxycycline, Vibramycin, Monodox, Doryx

  • See Also
  • Precautions
  1. AAP now approves Doxycycline for ANY age up to 21 day duration (esp. Tick Borne Illness)
  • Formulations
  1. Capsule (Doxycycline Monohydrate)
    1. Strengths: 50,75,100,150 mg (generics available)
  2. Tablet (Doxycycline Monohydrate)
    1. Strengths: 50,75,100,150 mg (generics available)
  3. Tablet (Doxycycline Hyclate)
    1. Strengths: 20,50,75,100,150 mg (generics available)
  4. Doxycyline Hyclate Delayed-Release (Doryx MPC)
    1. Expensive ($10/pill) formulated to by-pass the esophagus for less side effects
    2. Alternatively, take the doxycyline with 8 oz water and food
    3. (2016) Presc Lett 23(11)
  • Dosing
  • Adults (weight >45 kg)
  1. Typical dose: 100 mg orally twice daily
  2. Low doses, such as 50 mg daily, are often as effective for Acne Vulgaris
  3. Avoid substituting low-dose Doxycycline (Periostat, Oracea) products for systemic infections
  4. May substitute other Doxycycline salts
    1. Doxycycline hyclate (Vibramycin, Doryx)
    2. Doxycycline monohydrate (Monodox)
    3. (2013) Presc Lett 20(5):26
  • Pregnancy
  1. All Trimesters - Category D
  • Adverse Effects
  1. Photosensitivity
    1. Use sun protection (e.g. Sunscreen)
  2. Pill Esophagitis
    1. Take with 8 ounces fluid
  3. Drug-Induced Tooth Staining
    1. Compared with Tetracycline, Doxcycyline is unlikely to cause tooth staining in children, even under age 8 years.
    2. Frequency: Uncommon to rare
  4. Abdominal Pain
  5. Diarrhea
  • Drug Interactions
  1. Doxycycline Decreases Absorption Of Other Substances
    1. Antacid
    2. Calcium Supplementation
  2. Doxycycline Level Decreased By Other Substance
    1. Barbiturate
    2. Carbamazepine
    3. Rifampin
    4. Phenytoin
  • Pharmacokinetics
  1. Absorption: Not affected by food or milk intake (unlike Tetracycline)
  2. Peak Activity: >2.6 hours
  3. Half Life: 18-22 hours
  4. Primary Elimination: Renal (>40%)
  5. Other Elimination: Hepatic