Antibiotics and Their Types By WeTheDoctors Antibiotics are medications used to treat bacterial infections. They work by either killing bacteria (bactericidal) or stopping their growth (bacteriostatic). They do not work against viruses. Types of Antibiotics 1. Penicillins Example: Amoxicillin, Penicillin G Mechanism: Inhibit bacterial cell wall synthesis Common Uses: Strep throat, syphilis, dental infections 2. Cephalosporins Example: Ceftriaxone, Cephalexin Mechanism: Also inhibit cell wall synthesis; broader spectrum than penicillins Common Uses: Pneumonia, UTIs, skin infections 3. Macrolides Example: Azithromycin, Erythromycin Mechanism: Inhibit bacterial protein synthesis Common Uses: Respiratory infections, STIs, pertussis 4. Tetracyclines Example: Doxycycline, Tetracycline Mechanism: Inhibit protein synthesis Common Uses: Acne, chlamydia, malaria prophylaxis 5. Fluoroquinolones Example: Ciprofloxacin, Levofloxacin Mechanism: Inhibit DNA gyrase and topoisomerase Common Uses: UTIs, GI infections, bone/joint infections 6. Aminoglycosides Example: Gentamicin, Amikacin Mechanism: Disrupt bacterial protein synthesis (bactericidal) Common Uses: Severe gram-negative infections, sepsis 7. Sulfonamides Example: Co-trimoxazole (Trimethoprim-Sulfamethoxazole) Mechanism: Inhibit folic acid synthesis Common Uses: UTIs, Pneumocystis pneumonia, MRSA 8. Carbapenems Example: Meropenem, Imipenem Mechanism: Very broad-spectrum; inhibit cell wall synthesis Common Uses: Multidrug-resistant infections, hospital-acquired infections