Pharm

Doxycycline

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Doxycycline, Vibramycin, Monodox, Doryx

  • See Also
  1. Tetracyclines
  • Indications
  1. Skin disorders
    1. Methicillin-Resistant Staphylococcus aureus (MRSA) Skin Infections
    2. Acne Vulgaris
    3. Acne Rosacea
  2. Gastrointestinal disorders
    1. Helicobacter Pylori (part of quadruple therapy protocol)
  3. Tick Borne Illness
    1. Lyme Disease
    2. Human Granulocytic Anaplasmosis (Human Granulocytic Ehrlichiosis)
    3. Rocky Mountain Spotted Fever
    4. Ehrlichiosis
  4. Miscellaneous disorders
    1. Community Acquired Pneumonia
    2. Acute Exacerbation of Chronic Bronchitis
    3. Malaria Prophylaxis
    4. Anthrax
  5. Sexually Transmitted Disease
    1. Chlamydia trachomatis
    2. Lymphogranuloma venereum
    3. Pelvic Inflammatory Disease
  • Contraindications
  1. Pregnancy
  • Mechanism
  1. See Tetracyclines
  • Precautions
  1. AAP now approves Doxycycline for ANY age up to 21 day duration (esp. Tick Borne Illness)
  • Medications
  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
  • 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
  6. Pseudotumor Cerebri
    1. Rare Tetracycline class effect
  • Safety
  1. Pregnancy Category D (all trimesters)
  2. Unknown safety in Lactation
  • 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
  3. Food Related
    1. Doxycycline can be taken with milk or food (unlike Tetracycline)
    2. Take with a full glass of water (risk of Pill Esophagitis)
  4. Warfarin
    1. Increases INR
  • 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
  • Resources
  1. DailyMed (accessed 10/3/2021)
    1. https://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=712965e2-c089-46c3-9a86-d3f61673b25d
  2. DailyMed (accessed 10/3/2021)
    1. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=3e7cf78f-3b48-4614-9fa4-c6d1e0c05a35