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Tetracyclines

2 min read

Tetracyclines

Key Points

  • Tetracyclines are broad-spectrum bacteriostatic antibiotics that inhibit bacterial growth.
  • They bind the 30S ribosome and inhibit protein synthesis needed for bacterial cellular function.
  • Major safety concerns include photosensitivity, renal or hepatic impairment risk, and permanent tooth discoloration in young children.
  • Tetracyclines are contraindicated in pregnancy and in children younger than 8 years.
  • Absorption is reduced by dairy products, antacids, and iron products.
  • Expired tetracycline can become toxic and is linked to reversible nephrotoxicity (Fanconi syndrome).

Mechanism of Action

Tetracyclines penetrate the bacterial cell wall and bind the 30S ribosomal subunit, inhibiting protein synthesis and suppressing bacterial growth.

Clinical Use

  • Broad gram-positive and gram-negative bacterial infections.
  • Use may be limited by clinically significant side-effect burden.

Nursing Considerations

  • Check allergy history before administration.
  • Screen for contraindications: pregnancy and age younger than 8 years.
  • Use caution in renal or hepatic impairment.
  • For best absorption, give with a full glass of water on an empty stomach, at least 1 hour before or 2 hours after meals.
  • Avoid coadministration with milk/dairy products, antacids, or iron products because absorption is reduced.
  • Give at least 1 hour before bedtime to reduce esophageal irritation or ulceration risk.
  • Verify expiration date and do not administer expired tetracycline.
  • Monitor infection response: WBC trend, fever trend, infection-site findings, and culture data when available.

Side Effects and Adverse Effects

  • Common: GI upset, photosensitivity.
  • Infectious complications: oral candidiasis and C. diff.
  • Pediatric risk: permanent teeth discoloration and enamel defects in children younger than 8 years.
  • Neurologic warning: increased intracranial pressure with headache, blurred vision, diplopia, or vision loss.
  • Drug-effect interaction concern: reduced effectiveness of oral contraceptives.

Health Teaching

  • Avoid direct sunlight and use sunscreen/protective clothing.
  • Use backup contraception while taking tetracyclines if using oral contraceptives.
  • Stop medication and notify the provider immediately if pregnancy occurs.
  • Discard expired tetracycline immediately.
  • Report severe diarrhea, oral yeast symptoms, new severe headache, blurred vision, double vision, or vision loss promptly.

Self-Check

  1. Why should tetracyclines not be given with dairy products, antacids, or iron?
  2. Which symptoms suggest tetracycline-associated intracranial hypertension requiring urgent escalation?
  3. What is the safest nursing response if tetracycline is prescribed for a pregnant client or a child younger than 8 years?

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