Doxycycline
Vibramycin
Tetracycline antibiotic (bacteriostatic)
Binds 30S ribosomal subunit → blocks protein synthesis. Broad atypical/intracellular coverage. Also used for chemical pleurodesis.
Indications
- •Atypical pneumonia, tick-borne illness, MRSA (SSTI), malaria prophylaxis
- •Pleurodesis (sclerosant)
Dosing
| Context | Adult | Pediatric |
|---|---|---|
| Typical | 100 mg IV/PO q12h | — |
| Pleurodesis | 500 mg in the pleural space (very painful — needs intrapleural LA) | — |
Pharmacokinetics
Half-life ~18 h. Hepatic/biliary — no renal adjustment.
Side effects
- !Esophagitis (take upright with water)
- !Photosensitivity
- !Tooth discoloration (children <8, pregnancy)
- !Severe pain with pleurodesis
Contraindications
- ×Pregnancy
- ×Children <8 years
Clinical pearls
- ★Anesthesia crossover: doxycycline pleurodesis is intensely painful — plan intrapleural local anesthetic + systemic analgesia.
- ★No renal dose adjustment (unlike most tetracyclines' reputation).
Other drugs in Antibiotics
- Cefazolin
β-lactam — inhibits bacterial cell wall PBPs.
- Vancomycin
Inhibits cell wall synthesis (binds D-Ala-D-Ala). Active against MRSA + gram-positives.
- Clindamycin
Binds 50S ribosomal subunit, blocks peptide-bond formation. Bacteriostatic against most organisms; bactericidal against susceptible streptococci. Excellent activity against anaerobes and gram-positive cocci including community-acquired MRSA.
- Gentamicin
Binds 30S ribosomal subunit, causes misreading of mRNA → defective bacterial protein synthesis. Bactericidal, concentration-dependent killing. Synergy with cell-wall agents (β-lactams, vancomycin) for gram-positive endocarditis.
- Cefuroxime
β-lactam — inhibits cell-wall synthesis (PBP binding). 2nd-gen: gram-positive + expanded gram-negative.
- Cefepime
β-lactam cell-wall inhibitor. Broad gram-negative (incl. Pseudomonas) + gram-positive coverage.
- Cefotetan
β-lactam; adds anaerobic (B. fragilis) coverage → colorectal/gynecologic prophylaxis.
- Cefotaxime
β-lactam cell-wall inhibitor. Broad gram-negative + CNS penetration.
Browse all classes: /reference/drugs
Suggested reading
- •Miller's Anesthesia, 9e
- •FDA package insert
