Tetracyclines

Mechanism of Action and Pharmacology

• Tetracyclines work by inhibiting protein synthesis in bacteria.
• They bind to metallic ions, such as calcium, magnesium, and iron, to form insoluble complexes.
• This binding leads to chelation and drug-binding, which can affect absorption and efficacy.

Spectrum of Activity

• Tetracyclines are effective against a wide range of bacteria, including Gram-positive and Gram-negative bacteria, as well as some protozoa and rickettsiae.

Indications and Uses

• The most common drug in the tetracycline class is doxycycline (Vibramycin).
• Tetracyclines are indicated for treating a variety of infections, including urinary tract infections, respiratory tract infections, and sexually transmitted infections.
• Doxycycline is commonly used to treat acne, rosacea, and Lyme disease.

Adverse Effects

• A significant adverse effect of tetracyclines is related to calcium, as they can bind to calcium and lead to skeletal and dental deformities in fetuses, children, and nursing infants.
• Tetracyclines can also cause superinfections, which can lead to alterations in intestinal flora.
• Patients taking tetracyclines should avoid taking antacids, calcium supplements, and iron preparations, as they can reduce the absorption of the antibiotic.

Nursing Implications

• Tetracyclines can increase the risk of photosensitivity, so patients should avoid sunlight exposure and use sunscreen and protective clothing.
• Nurses should monitor patients for signs of superinfection, such as diarrhea or vaginal itching, and report any changes to the healthcare provider.