Dosing and uses of Tetracycline
Adult dosage forms and strengths
capsule/tablet
- 250mg
- 500mg
syrup (extemporaneously prepared)
- 125mg/5mL
Chronic Bronchitis, Acute Exacerbation
500 mg PO q6hr
Acne
250-500 mg PO q12hr
Ehrlichiosis
500 mg PO q6hr for 7-14 days
Vibrio Cholera
500 mg PO q6hr for 3 days
Malaria, Severe Treatment (Unlabeled)
500 mg PO q6hr for 7 days with quinidine gluconate
Dosage modifications
Renal impairment
- CrCl 50-80 mL/min: Dose frequency q8-12hr
- CrCl 10-50 mL/min: Dose frequency q12-24hr
- CrCl <10 mL/min: Dose frequency q24hr
Dosing Considerations
Susceptible organisms
- Acinetobacter spp, Actinomyces israelii, Afipia felis, Bacillus anthracis, Bacteroides spp, Bartonella bacilliformis, Bartonella quintana, Bordetella pertussis, Borrelia recurrentis, Brucella spp, Capnocytophaga canimorsus, Campylobacter jejuni, Chlamydia spp, Citrobacter spp, Coxiella burnetii, Eikenella corrodens, Escherichia coli, Francisella tularensis, Leptospira interrogans, Helicobacter pylori, Klebsiella spp, Listeria monocytogenes, Moraxella catarrhalis, Mycoplasma pneumoniae, Neisseria gonorrhoeae, Propionibacterium acnes, Rickettsiae, Shigella spp, Staphylococcus aureus, Streptococcus pneumoniae, Treponema pallidum, Ureaplasma urealyticum, Vibrio cholerae, Yersinia pestis, Yersinia enterocolitica, Yersinia pseudotuberculosis
Pediatric dosage forms and strengths
capsule/tablet
- 250mg
- 500mg
syrup
- 125mg/5mL
General Dosing Guidelines
<8 years: Not recommended; tooth discoloration and enamel hypoplasia may occur with use in young children
>8 years: 25-50 mg/kg/day PO divided q6hr; not to exceed 3 g/day
Malaria, Severe Treatment (Unlabeled)
<8 years: Not recommended; tooth discoloration and enamel hypoplasia may occur with use in young children
>8 years: 25-50 mg/kg/day PO divided q6hr, not to exceed 250 mg/dose q6hr for 7 days with quinidine gluconate
Vibrio Cholera
Single dose: 25 mg/kg PO; not to exceed 1 g/dose
Multiple dose: 40 mg/kg/day PO divided q6hr for 3 days; not to exceed 2 g/day
Administration
Take on empty stomach; do not take with dairy products
Tetracycline adverse (side) effects
>10%
Discoloration of teeth and enamel hypoplasia (young children)
1-10%
Diarrhea
Nausea
Photosensitivity
<1%
Anorexia
Abdominal cramps
Antibiotic-associated pseudomembranous colitis
Bulging fontanels in infants
Diabetes insipidus syndrome
Esophagitis
Exfoliative dermatitis
Incr ICp
Pericarditis
Pseudotumor cerebri
Pancreatitis
Pruritus
Pigmentation of nails
Vomiting
Warnings
Contraindications
Documented hypersensitivity
Severe hepatic dysfunction
Cautions
Photosensitivity may occur with prolonged exposure to sunlight or tanning equipment
Reduce dose in renal impairment
Consider drug serum level determinations in prolonged therapy
Tetracycline use during tooth development (last half of pregnancy through age 8 years) can cause permanent discoloration of teeth
Fanconilike syndrome may occur with outdated tetracyclines
IV/IM no longer commercially available
Pregnancy and lactation
Pregnancy category: D (systemic), C (periodontal fiber)
Lactation: Enters breast milk; some manufacturers say do not nurse; however, AAP considers nursing compatible due to calcium chelation of drug and prevention of its absorption (long-term safety of prolonged exposure unknown)
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Tetracycline
Mechanism of action
Inhibits bacterial protein synthesis by binding with 30S and possibly 50S ribosomal subunit(s)
Absorption
Absorption: 75% (PO)
Peak plasma time: 2-4 hr (PO)
Distribution
Small amount appears in bile; relative diffusion from blood into CSF: good only with inflammation (exceeds usual MICs) CSF: blood level ratio: inflamed meninges: 25%
Protein bound: 65%
Elimination
Half-life: 8-11 hr (normal renal function); 57-108 hr (end-stage renal disease)
Excretion: Urine (60% as unchanged drug); feces (as active form)
