Doxycycline
Forms
Doxycycline comes in 100mg capsules.
Dosage
- Adults: 100 mg daily with food and a large glass of water.
- Children: 2 mg/kg/day (maximum 100 mg) for children >8 years old. Not recommended for younger children.
Directions for prevention
Begin one day before travel and continue daily for duration of stay in malaria zone and for four weeks after leaving malaria zone.
Note: It is critical that this drug be taken faithfully every day. Missing even one day may lead to malaria symptoms.
Note: Travelers taking minocycline for other reasons should stop minocycline one or two days prior to departure, start doxycycline, and then resume minocycline after completing standard doxycycline malaria prevention program.
Adverse Effects
This medication can cause the following.
- Irritation of the stomach or esophagus (esophagitis, esophageal ulcers) and should always be taken in the middle of a meal and with a large glass of water.
- Vaginal yeast infections (candidiasis). Female travelers may want to carry a self treatment kit (canesten-monistat).
- Bone lesions and staining and deformity of teeth in children up to 8 years old and in newborns when given to pregnant women after the fourth month of pregnancy.
- Bad sunburns. To prevent this use a Titanium Dioxide containing sun blockers (Ombrelle Extreme)
Pregnancy
Use of doxycycline is contraindicated during pregnancy.
Interactions with Other Drugs
- Alcohol: Decreased absorption of doxycycline in alcoholics
- Antacids: Decreased doxycycline effect when taken at same time; take 3 hours apart
- Anticoagulants, oral (Coumadin, and others): Increased anticoagulant effect
- Barbiturates: Decreased doxycycline effect
- Bismuth subsalicylate (Pepto-Bismol): Decreased doxycycline effect
- Carbamazepine (Tegretol): Decreased doxycycline effect
- Contraceptives, oral: Decreased contraceptive effect
- Digoxin (Lanoxin, and others): Possible digoxin toxicity
- Lithium: Lithium toxicity due to decreased renal excretion
- Methotrexate (Rheumatrex, and others): Possible increased toxicity
- Molindone (Moban): Decreased doxycycline absorption; take at least 2 hours apart
- Phenformin: Lactic acidosis
- Phenytoin (Dilantin, and others): Decreased doxycycline effect
- Rifampin: Possible decreased doxycycline effect
- Theophylline: Possible theophylline toxicity
- Zinc: Decreased doxycycline effect.