Tetracycline
SUMYCIN
Pronunciation: tet-ra-SYE-kleen
“Some mice Tetris cycling”
What it isInhibitor of the 30S ribosomal subunit; H. pylori regimens, rickettsial and atypical infection.
Why this oneIt remains part of bismuth quadruple therapy for resistant H. pylori.
What limits itFour-times-daily dosing on an empty stomach, and cations block absorption. Avoid in pregnancy and young children.
FDA-approved for
- bacterial infections (1953)
- acne (1953)
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Susceptible bacterial infections | Adults | 500 mg BID or 250 mg QID | 500 mg BID or 250 mg QID | 500 mg QID (severe/unresponsive infections) |
| Susceptible bacterial infections | Pediatric >8 yr | 25–50 mg/kg/day (10–20 mg/lb) divided QID | 25–50 mg/kg/day divided QID | 50 mg/kg/day |
| Acne (moderate–severe, adjunctive long-term) | Adults | 1 g/day in divided doses | Maintenance 125–500 mg/day | 1 g/day |
Renal Reduce total dosage in renal impairment (lower individual doses and/or extend dosing intervals)
Hepatic Undefined
Instructions
- Take with adequate fluid to reduce esophageal irritation/ulceration; avoid dosing at bedtime
- Avoid antacids (aluminum/calcium/magnesium), iron, zinc, sodium bicarbonate, food, and dairy — they impair absorption
- Avoid during tooth development (pregnancy through age 8) — permanent tooth discoloration
- For streptococcal infections continue therapy for 10 days
Available strengths
- cap 250, 500 mg
- tab 250, 500 mg
- sol 30 mg/mL
- ointment 30 mg/mL
- spray 30 mg/mL
Cautions
- Permanent tooth discoloration and enamel hypoplasia during tooth development
- Esophagitis and esophageal ulceration (esp. capsule taken at bedtime)
- Hepatotoxicity/liver failure, especially with renal impairment
- Photosensitivity
- Increased BUN (dose-related)
- Superinfection/Candida overgrowth
Adverse reactions
- Nausea
- Vomiting
- Diarrhea
- Epigastric distress
- Glossitis / dysphagia
- Rash
- Photosensitivity
- Tooth discoloration
Pregnancy Undefined
Lactation Undefined
Cost
Generic entry1985
NO BOXED WARNINGS
Principal riskFour-times-daily on an empty stomach; cations block it
Classes and tags
Clinical profile
Legacy pregnancy categoryD
Defining liabilityAllergy, gastrointestinal effects and agent-specific renal, hepatic, hematologic or interaction risks.
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