Doxycycline

An antibiotic with anti-inflammatory properties commonly used for a variety of dermatologic conditions (e.g., acne, rosacea, inflammatory dermatoses) and certain infections.

Important Instructions

  • Take with food to reduce stomach upset (mild nausea/stomach upset common on an empty stomach).

  • Take with a full glass of water at least 1 hour before bed and remain upright for at least 30–60 minutes after taking.

    • This medication can cause esophagitis or esophageal ulceration if it lodges in the esophagus.

  • Avoid excessive sun exposure.

    • Doxycycline significantly increases sun sensitivity and can cause severe sunburn. Use sunscreen, protective clothing, and avoid tanning beds.

Common Things to Avoid

  • Mineral supplements (iron, calcium, magnesium, zinc, aluminum) within 2 hours before or after taking doxycycline
    → These can reduce absorption.

  • Dairy products within 2 hours of dosing
    → May reduce absorption (less than older tetracyclines, but still clinically relevant).

  • Alcohol
    → Not strictly contraindicated, but may worsen GI side effects.

  • Hormonal contraceptives
    → Evidence of reduced efficacy is limited, but a backup method (e.g., condoms) is often recommended during use as a precaution.

  • Antibiotics can increase the risk of yeast infections.

Contraindications

  • Pregnancy (risk to fetal bone and tooth development).

  • Children under 8 years old (permanent tooth discoloration and enamel effects).

Important Drug Interactions

  • Isotretinoin (Accutane)
    → Increased risk of pseudotumor cerebri (elevated intracranial pressure).

  • Warfarin
    → May increase INR and bleeding risk.

  • Methotrexate
    → May increase methotrexate levels and toxicity.

Note: Direct oral anticoagulants (e.g., apixaban, dabigatran) are not absolute contraindications, but caution is advised.

Serious Side Effects (Rare, but Important)

  • Esophagitis / Esophageal ulceration

    • Severe chest pain, painful swallowing, burning sensation, vomiting blood, dark or tarry stools.

  • Pseudotumor cerebri (increased intracranial pressure)

    • Persistent headache, visual changes, nausea, vomiting.

  • Severe skin reactions

    • Blistering or peeling rash.

  • Allergic reactions

    • Hives, swelling of face/lips/tongue, difficulty breathing.

  • Severe or persistent diarrhea

    • Possible C. difficile infection.