doxycycline
(dox i sye' kleen)
Adoxa, Apo-Doxy (CAN), Doryx, Doxy 100, Doxy 200, Doxycin (CAN), Monodox, Novo-Doxylin (CAN), Nu-Doxycycline (CAN),Periostat, Vibra-Tabs, Vibramycin
Pregnancy Category D
Drug classes
Antibiotic
Tetracycline antibiotic
Therapeutic actions
Bacteriostatic: Inhibits protein synthesis of susceptible bacteria, causing cell death.
Indications
· Infections caused by rickettsiae; M. pneumoniae; agents of psittacosis, ornithosis, lymphogranuloma venereum and granuloma inguinale; B. recurrentis; H.ducreyi; P. pestis; P. tularensis; B. bacilliformis; Bacteroides; V. comma; V. fetus; Brucella; E. coli; E. aerogenes; Shigella; A. calcoaceticus; H.influenzae; Klebsiella; D. pneumoniae; S. aureus
· When penicillin is contraindicated, infections caused by N. gonorrhoeae, T. pallidum, T. pertenue, L. monocytogenes, Clostridium, B. anthracis, Chlamydia psittaci, C. trachomatis
· Oral tetracyclines used for acne, uncomplicated adult urethral, endocervical, or rectal infections caused by C. trachomatis
· Acute intestinal amebiasis
· Reduction of incidence and progression of disease following exposure to anthrax
· Prophylaxis for malaria due to Plasmodium falciparum for short-term use in travelers
· Treatment of periodontal disease as an adjunct to scaling and root planing
· Unlabeled use: Prevention of "traveler's diarrhea" commonly caused by enterotoxigenic E. coli
Contraindications and cautions
· Contraindicated with allergy to tetracyclines.
· Use cautiously with renal or hepatic dysfunction, pregnancy, lactation.
Available forms
Tablets—50, 75, 100 mg; capsules—50, 100 mg; coated pellets, capsules—75, 100 mg; powder for oral suspension—25 mg; syrup—50 mg; powder for injection—100, 200 mg
Dosages
ADULTS
200 mg IV in one or two infusions (each over 1–4 hr) on the first treatment day, followed by 100–200 mg/day IV, depending on the severity of the infection, or 200 mg PO on day 1, followed by 100 mg/day PO.
· Primary or secondary syphilis: 300 mg/day IV for 10 days; or 100 mg q 12 hr PO on the first day, followed by 100 mg/day as one dose or 50 mg q 12 hr PO.
· Acute gonococcal infection: 200 mg PO, then 100 mg hs, followed by 100 mg bid for 3 days; or 300 mg PO followed by 300 mg in 1 hr.
· Primary and secondary syphilis: 300 mg/day PO in divided doses for at least 10 days.
· Traveler's diarrhea: 100 mg/day PO as prophylaxis.
· Malaria prophylaxis: 100 mg PO daily.
· Anthrax prophylaxis: 100 mg PO bid for 60 days.
· CDC recommendations for STDs: 100 mg bid PO for 7–10 days.
· Periodontal disease: 20 mg PO bid, following scaling and root planing.
PEDIATRIC PATIENTS
> 8 yr and < 100 lb: 4.4 mg/kg, IV in one or two infusions, followed by 2.2–4.4 mg/kg/day IV in one or two infusions; or 4.4 mg/kg, PO in two divided doses the first day of treatment, followed by 2.2–4.4 mg/kg/day on subsequent days.
> 8 yr and > 100 lb: Use adult dosage.
· Malaria prophylaxis: 2 mg/kg/day PO, up to 100 mg/day.
· Anthrax prophylaxis: 2.2 mg/kg PO bid for 60 days.
GERIATRIC PATIENTS OR PATIENTS WITH RENAL FAILURE
IV doses of doxycycline are not as toxic as other tetracyclines in these patients.
Pharmacokinetics
Route | Onset | Peak |
Oral | Varies | 1.5–4 hr |
IV | Rapid | End of infusion |
Metabolism: T1/2: 15–25 hr
Distribution: Crosses placenta; enters breast milk
Excretion: Feces, urine
IV facts
Preparation: Prepare solution of 10 mg/mL, reconstitute with 10 mL (100-mg vial): 20 mL (200 mg vial) of sterile water for injection; dilute further with 100–1,000mL (100-mg vial) or 200–2,000 mL (200-mg vial) of sodium chloride injection, 5% dextrose injection, Ringer's injection, 10% invert sugar in water, lactated Ringer's injection, 5% dextrose in lactated Ringer's, Normosol-M in D5W, Normosol-R in D5W, or Plasma-Lyte 56 or 148 in 5% Dextrose. If mixed in lactated Ringer's or 5% dextrose in lactated Ringer's, infusion must be completed within 6 hr after reconstitution; otherwise, may be stored up to 72 hr if refrigerated and protected from light, but infusion should then be completed within 12 hr; discard solution after that time.
Infusion: Infuse slowly over 1–4 hr.
Adverse effects
· Dental: Discoloring and inadequate calcification of primary teeth of fetus if used by pregnant women, discoloring and inadequate calcification of permanent teeth if used during period of dental development
· Dermatologic: Phototoxic reactions, rash, exfoliative dermatitis (more frequent and more severe with this tetracycline than with any others)
· GI: Fatty liver, liver failure, anorexia, nausea, vomiting, diarrhea, glossitis, dysphagia, enterocolitis, esophageal ulcer
· Hematologic: Hemolytic anemia, thrombocytopenia, neutropenia, eosinophilia, leukocytosis, leukopenia
· Local: Local irritation at injection site
· Other: Superinfections, nephrogenic diabetes insipidus syndrome
Interactions
Drug-drug
· Decreased absorption with antacids, iron, alkali
· Decreased therapeutic effects with barbiturates, carbamazepine, phenytoin
· Increased digoxin toxicity with doxycycline
· Increased nephrotoxicity with methoxyflurane
· Decreased activity of penicillins
Drug-food
· Decreased effectiveness of doxycycline if taken with food, dairy products
Drug-lab test
· Interference with culture studies for several days following therapy
Nursing considerations
Assessment
· History: Allergy to tetracyclines, renal or hepatic dysfunction, pregnancy, lactation
· Physical: Skin status, R and sounds, GI function and liver evaluation, urinary output and concentration, urinalysis and BUN, LFTs, renal function tests; culture infected area before beginning therapy
Interventions
· Administer the oral medication without regard to food or meals; if GI upset occurs, give with meals; patients being treated for periodontal disease should receive tablet at least 1 hr before morning and evening meals.
· Protect patient from light and sun exposure.
· Take drug throughout the day for best results; if GI upset occurs, take drug with food. If being treated for periodontal disease, take at least 1 hour before morning and evening meals.
· Avoid pregnancy while using this drug; using barrier contraceptives is advised.
· You may experience these side effects: Sensitivity to sunlight (wear protective clothing, use sunscreen), diarrhea.
· Report rash, itching, difficulty breathing, dark urine or light-colored stools, pain at injection site.
Adverse effects in Italic are most common; those in Bold are life-threatening.
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