Tetracyclines

Nursing pharmacology study reference (NCLEX-style monograph). Numeric values are standard teaching ranges for study and must be verified against current manufacturer labeling before clinical use. This is educational content, not prescribing guidance.

Tetracyclines — Antibacterial; Tetracycline.

Identification

• Therapeutic class: Antibacterial.
• Pharmacologic class: Tetracycline.

Pharmacology

• Mechanism of action: Bind the 30S ribosomal subunit to inhibit protein synthesis (bacteriostatic).
• Onset / peak / duration: Rapid; once or twice daily.
• Half-life / therapeutic level: Doxycycline about 18 hours; no routine level.

Clinical use

• Indications: Respiratory infections, acne, tick-borne diseases (Rocky Mountain spotted fever, Lyme), chlamydia, malaria prophylaxis (doxycycline).
• Usual dose, route, frequency: Doxycycline PO once or twice daily; IV available.
• Maximum dose / adjustments: Avoid in children under 8 and in pregnancy.

Safety

• Contraindications: Pregnancy, lactation, children under 8 (tooth staining and bone effects), hypersensitivity.
• Black box warning: None.
• Interactions: Dairy, antacids, iron, and calcium bind the drug and reduce absorption (separate doses); warfarin, oral contraceptives, isotretinoin (intracranial hypertension).
• Pregnancy / lactation: Contraindicated.
• High-alert: No.

Adverse effects

• Common side effects: Photosensitivity, GI upset, esophageal irritation.
• Serious effects to report: Severe sunburn, esophageal ulceration, intracranial hypertension (headache, vision changes), C. difficile colitis.
• Antidote / reversal: Supportive care.

Nursing process

• Assessment before administration: Allergy, pregnancy status, age, photosensitivity risk.
• Interventions during therapy: Take with a full glass of water and remain upright; avoid dairy and binders around dosing.
• Monitor: Skin, GI tolerance, infection resolution.
• Evaluation / expected outcome: Resolution of infection or acne improvement.

Patient teaching

• Patient teaching: Use sun protection; do not lie down right after a dose; avoid dairy, antacids, and iron near dosing; backup contraception.
• Notify provider if: Severe headache or vision changes, painful swallowing, severe sunburn.
• Administration tips: Full glass of water, stay upright; separate from dairy and mineral binders by 2 hours.