Final answer:
Tetracyclines have a broad spectrum of activity and inhibit bacterial protein synthesis, but they are not suitable for infections that require narrow-spectrum antimicrobial drugs due to potential side effects like phototoxicity, teeth discoloration, and liver toxicity.
Step-by-step explanation:
Tetracyclines are a class of antibiotics with a broad spectrum of activity, making them a drug of choice for numerous infections. They work by binding to the 30S ribosomal subunit of bacteria, blocking the binding of tRNA, which in turn inhibits protein synthesis. Thus, tetracyclines are effective against a variety of bacterial pathogens. Nevertheless, there are several side effects associated with tetracycline use. These include phototoxicity, permanent discoloration of developing teeth, and liver toxicity with high doses or in patients with kidney impairment. Due to these side effects, tetracyclines are not the first choice for certain conditions, for example, infections requiring a narrow-spectrum antimicrobial drug would be inappropriate for tetracycline treatment.