Tetracycline

A first-generation tetracycline antibiotic with broad-spectrum activity.

What is Tetracycline?

Tetracycline is a broad-spectrum antibiotic effective against Gram-positive, Gram-negative, and atypical bacteria.

It was one of the earliest antibiotics used worldwide.

History & Background

Tetracycline was introduced in the 1950s and became widely used due to its broad antibacterial coverage and oral availability.

Chemical Structure & Properties

• IUPAC name: (4S,4aR,5S,5aR,6S,12aS)-4-(dimethylamino)-1,4,4a,5,5a,6,11,12a-octahydro-3,6,10,12,12a-pentahydroxy-6-methyl-1,11-dioxo-2-naphthacenecarboxamide
• Molecular formula: C₂₂H₂₄N₂O₈
• Molar mass: 444.43 g/mol
• Functional groups: Amide, phenolic OH, tertiary amine

Mechanism of Action

Tetracycline inhibits bacterial protein synthesis by:

• Binding to the 30S ribosomal subunit
• Preventing attachment of aminoacyl-tRNA
• Stopping bacterial growth (bacteriostatic)

Pharmacokinetics

• Absorption: Moderate oral absorption
• Peak plasma time: 2–4 hours
• Half-life: 6–12 hours
• Metabolism: Minimal
• Excretion: Urine and bile

Medical Uses

• Acne vulgaris
• Respiratory tract infections
• Chlamydial infections
• Rickettsial infections

Dosage Guidelines

Adults: 250–500 mg every 6 hours

Duration: As prescribed

⚠️ Take on an empty stomach for best absorption.

Side Effects

• Nausea
• Vomiting
• Photosensitivity
• Tooth discoloration

Warnings & Precautions

• Not recommended in pregnancy
• Avoid in children under 8 years
• Can permanently discolor teeth

Drug Interactions

• Milk and dairy products
• Antacids and iron supplements
• Oral contraceptives

Frequently Asked Questions

Is tetracycline still used? – Yes, but less than newer agents.

Can it cause yellow teeth? – Yes.

Does food affect absorption? – Yes.

Is it safe long-term? – Only with monitoring.

⚠️ Educational content only. Not a substitute for professional medical advice.