Tetracycline
Mechanism :
The tetracyclines are primarily bacteriostatic and are thought to exert their antimicrobial effect by the inhibition of protein synthesis. The tetracyclines, including minocycline, have similar antimicrobial spectra of activity against a wide range of gram-positive and gram-negative organisms. Cross-resistance of these organisms to tetracyclines is common.
Indication :
- Acne
- Chlamydia
- Non-gonococcal urethritis
- Trachoma
- Lymphogranuloma venereum
- Plague
Contraindications :
This drug is contraindicated in persons who have shown hypersensitivity to any of the tetracyclines, in children <8 years. Avoid in complete renal failure. Use with caution in patients with hepatic dysfunction.
Dosing :
Oral:
>8 years:
25-50 mg/kg/day orally divided every 6 hours. Max: 3 g/day.
Adverse Effect :
Fever and discoloration of secretions, anorexia, nausea, vomiting, diarrhea, dyspepsia, stomatitis, glossitis, dysphagia, enamel hypoplasia, enterocolitis, pseudomembranous colitis, pancreatitis, inflammatory lesions, hyperbilirubinemia, autoimmune hepatitis, alopecia, erythema nodosum, hyperpigmentation of nails, pruritus, toxic epidermal necrolysis, and vasculitis. bone discoloration, exacerbation of systemic lupus erythematosus and pulmonary infiltrates with eosinophilia hemolytic anemia, thrombocytopenia, leukopenia, neutropenia, pancytopenia, brown-black microscopic discoloration of the thyroid gland (on prolonged use). Tooth discoloration in children less than 8 years of age.
Interaction :
Anticoagulant therapy: May require downward adjustment of their anticoagulant dosage.
Penicillin: May interfere with the bactericidal action of penicillin, it is advisable to avoid giving tetracycline-class drugs in conjunction with penicillin.
Antacids: Absorption of is impaired by antacids containing aluminium, calcium, or magnesium, and iron-containing preparations.
Oral Contraceptives: Concurrent use of tetracyclines with oral contraceptives may render oral contraceptives less effective.
Renal Dose :
Dose in Renal Impairment GFR (mL/min)
20-50 | Dose as in normal renal function |
10-20 | Dose as in normal renal function |
<10 | 250 mg 4 times a day |
Dose in Patients undergoing Renal Replacement Therapies
CAPD | Not dialysed. Dose as in GFR<10 mL/min |
HD | Not dialysed. Dose as in GFR<10 mL/min |
HDF/High flux | Unknown dialysability. Dose as in GFR<10 mL/min |
CAV/VVHD | Unlikely to be dialysed. Dose as in GFR=10–20 mL/min |
Hepatic Dose :
Dose adjustment may be required, in patients with pre-existing hepatic impairment due to increased risk of hepatotoxicity.