Doxycycline is a broad-spectrum tetracycline antibiotic used to treat:
- Bacterial infections (UTIs, respiratory, skin, sexually transmitted infections like chlamydia and gonorrhea)
- Acne and rosacea
- Gum disease (periodontitis)
- Lyme disease, malaria prevention
Dosage & Administration
- Take with food and a full glass of water to prevent stomach/esophageal irritation.
- Standard dose:
- Adults: 100 mg twice daily or 200 mg once daily (varies by infection).
- Children ≥9 years: Weight-based dosing (consult doctor).
- Do not crush or chew delayed-release capsules.
- Avoid dairy, antacids, or iron supplements within 2-3 hours of taking doxycycline (reduces absorption).
- Shake oral suspension well before use; measure with dosing spoon.
Precautions
- May cause tooth discoloration in children <9 years.
- Increases sun sensitivity—avoid prolonged UV exposure (use sunscreen).
- Long-term use requires monitoring:
- Liver/kidney function
- Blood cell counts
- Not for use in:
- Pregnancy (2nd/3rd trimester)
- Breastfeeding mothers
- Severe liver disease
Contraindications
Do not use if you have:
- Allergy to doxycycline or tetracyclines
- Porphyria, severe liver disease
- Leukopenia (low white blood cells)
Possible Side Effects
Common:
- Nausea, diarrhea, stomach upset
- Sun sensitivity, mild rash
- Vaginal yeast infection (women)
Serious (seek medical help):
- Severe headache, blurred vision (intracranial pressure risk)
- Yellow skin/dark urine (liver problems)
- Severe diarrhea (C. difficile infection)
- Allergic reaction (swelling, difficulty breathing)
Drug Interactions
Avoid or space out:
- Antacids (calcium, magnesium, aluminum)
- Iron supplements
- Bismuth subsalicylate (Pepto-Bismol)
- Warfarin (increased bleeding risk)
- Seizure meds (phenytoin, carbamazepine)
Missed Dose & Overdose
- Missed dose: Take as soon as remembered. Skip if close to next dose.
- Overdose symptoms: Severe nausea, vomiting, diarrhea → Seek medical help.
Storage
- Keep at 15-25°C (59-77°F) in a dry, dark place.
- Keep away from children and pets.
- Discard expired medication.
Note: Always complete the full course, even if symptoms improve. Consult your doctor before combining with other medications.