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Pharmacologic class: Tetracycline
Therapeutic class: Anti-infective
Pregnancy risk category D
Unclear. Thought to inhibit bacterial protein synthesis at 30S and 50S ribosomal subunit and to alter cytoplasmic membrane of susceptible organisms.
Capsules: 50 mg, 100 mg, 150 mg
Capsules (coated pellets): 40 mg, 75 mg, 100 mg
Powder for injection: 100 mg, 200 mg
Powder for oral suspension: 25 mg/5 ml
Syrup: 50 mg
Tablets: 20 mg, 50 mg, 75 mg, 100 mg
Indications and dosages
Adults: 40 mg P.O. daily in the morning
➣ Infections caused by various organisms, including Mycoplasma, Chlamydia, and Rickettsia organisms, and Borrelia burgdorfer
Adults and children weighing more than 45 kg (99 lb): 100 mg P.O. q 12 hours on first day, followed by 100 to 200 mg P.O. once daily; or 50 to 100 mg P.O. q 12 hours; or 200 mg I.V. once daily; or 100 mg I.V. q 12 hours on first day, followed by 100 to 200 mg I.V. once daily; or 50 to 100 mg I.V. q 12 hours
Children weighing 45 kg (99 lb) or less: 2.2 mg/kg P.O. q 12 hours on first day, followed by 2.2 to 4.4 mg/kg/day P.O. once daily; or 1.1 to 2.2 mg/kg P.O. q 12 hours; or 4.4 mg/kg I.V. once daily; or 2.2 mg/kg I.V. q 12 hours on first day, followed by 2.2 to 4.4 mg/kg I.V. once daily; or 1.1 to 2.2 mg/kg I.V. q 12 hours
➣ Gonorrhea in penicillin-allergic patients
Adults and children weighing more than 45 kg (99 lb): 100 mg P.O. q 12 hours for 7 days; or 300 mg P.O. initially, followed by another 300 mg P.O. 1 hour later
➣ Lyme disease
Adults and children weighing more than 45 kg (99 lb): 100 mg P.O. b.i.d. for 10 to 30 days
Adults and children weighing more than 45 kg (99 lb): 20 mg P.O. b.i.d. for up to 9 months
Adults and children weighing more than 45 kg (99 lb): 100 mg P.O. b.i.d. for 60 days; or 100 mg I.V. q 12 hours for 60 days, changing to oral route when appropriate
Children weighing 45 kg (99 lb) or less: 2.2 mg/kg P.O. b.i.d. for 60 days; or 100 mg I.V. q 12 hours for 60 days, changing to oral route when appropriate
➣ Prevention of malaria caused by Plasmodium falciparum in short-term travelers (less than 4 months)
Adults: 100 mg/day P.O. starting 1 to 2 days before travel begins and continuing during and for 4 weeks after travel
Children: 2 mg/kg/day P.O., up to adult dosage of 100 mg/day, starting 1 to 2 days before travel begins and continuing during and for 4 weeks after travel
• Traveler's diarrhea
• Pleural effusion
• Hypersensitivity to drug, other tetracyclines, or bisulfites (with some drug products)
Use cautiously in:
• renal disease, hepatic impairment, nephrogenic diabetes insipidus, cachexia
• pregnant or breastfeeding patients
• children younger than age 8.
• Obtain specimens for culture and sensitivity testing, as ordered, before first dose.
☞ Don't give in conjunction with methoxyflurane anesthetic. Severe or fatal kidney damage may result.
• Reconstitute powder for injection with dextrose 5% in water, normal saline solution, lactated Ringer's solution, or dextrose 5% in lactated Ringer's solution.
• Don't infuse solutions with concentrations above 1 mg/ml.
• Infuse 100-mg dose over at least 1 hour.
• Complete infusion within 12 hours of dilution, unless diluted with lactated Ringer's solution or dextrose 5% in lactated Ringer's solution; in this case, complete infusion within 6 hours.
☞ Don't give during last half of pregnancy or to children under age 8 unless other drugs are likely to be ineffective or are contraindicated. Drug may retard bone growth and cause tooth discoloration and malformation.
• Be aware that capsules with coated pellets contain immediate- and delayed-release pellets.
CNS: paresthesia, pseudotumor cerebri
CV: phlebitis, thrombophlebitis, pericarditis
EENT: vestibular reactions, hoarseness, pharyngitis
GI: nausea, vomiting, diarrhea, esophagitis, epigastric distress, enterocolitis, anogenital lesions or inflammation, glossitis, oral candidiasis, black hairy tongue, pancreatitis
GU: dark yellow or brown urine, vaginal candidiasis
Hematologic: hemolytic anemia, neutropenia, thrombocytopenia
Musculoskeletal: bone growth retardation (in children younger than age 8)
Skin: photosensitivity, maculopapular or erythematous rash, hyperpigmentation, urticaria
Other: tooth enamel defects, increased appetite, phlebitis at I.V. site, superinfection, hypersensitivity reactions including anaphylaxis
Drug-drug. Adsorbent antidiarrheals; antacids; calcium, iron, and magnesium preparations: decreased doxycycline absorption
Barbiturates, carbamazepine, hormonal contraceptives containing estrogen, phenytoin, rifamycin: decreased doxycycline efficacy
Cholestyramine, colestipol: decreased oral absorption of doxycycline
Methoxyflurane: increased nephrotoxicity
Penicillin: decreased penicillin activity
Sucralfate: prevention of doxycycline absorption from GI tract
Warfarin: enhanced warfarin effects
Drug-diagnostic tests. Alkaline phosphatase, alanine aminotransferase, amylase, aspartate aminotransferase, bilirubin, blood urea nitrogen (BUN), eosinophils: increased levels
Hemoglobin, neutrophils, platelets, white blood cells: decreased levels
Urine catecholamines: false elevations
Drug-food. Calcium-containing foods: decreased drug absorption
Drug-behaviors. Alcohol use: decreased anti-infective effect of doxycycline
Sun exposure: increased risk of photosensitivity
• Evaluate I.V. site regularly. Apply cool compresses as needed.
☞ Monitor for hypersensitivity reactions, including anaphylaxis.
• Monitor hepatic profile, CBC, BUN, and creatinine levels.
• Assess for hypercoagulability in patients taking warfarin concurrently.
• Monitor for digoxin toxicity in patients taking digoxin concurrently.
• Advise patient to take with 8 oz of water to ensure passage into stomach.
• Tell patient to take on empty stomach at least 1 hour before meals or 2 hours afterwards.
• Instruct patient to take at least 1 hour before bedtime to prevent esophagitis.
☞ Tell patient to immediately report painful swallowing, abdominal pain, easy bruising or bleeding, or signs of hypersensitivity (such as rash).
• Advise female patient to tell prescriber if she is pregnant.
• Instruct patient to avoid alcohol use and large amounts of calcium-containing foods (such as dairy products and some green leafy vegetables, such as spinach).
• Stress importance of good oral hygiene.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, foods, and behaviors mentioned above.