Tetracycline

SUMYCIN

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

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

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

Pregnancy Undefined

Lactation Undefined

NO BOXED WARNINGS

Principal riskFour-times-daily on an empty stomach; cations block it

Cost, est. cash$20–$1,500/dose or month

Generic entry1985

Therapeutic safety burden1 / 4

Overdose danger1 / 4

Weight-gain liability0 / 4

Sedation liability0 / 4

QT / Torsades0 / 4

Direct muscarinic antagonism0 / 4

Embryofetal risk2 / 4

Legacy pregnancy categoryD

Defining liabilityAllergy, gastrointestinal effects and agent-specific renal, hepatic, hematologic or interaction risks.

no kinetic interactions