1. TETRACYCLINES Target: 30S ribosomal subunit of bacteria. Action: Tetracyclines bind reversibly to the 30S subunit. They block the attachment of aminoacyl-tRNA to the mRNA-ribosome complex. This prevents addition of new amino acids to the growing peptide chain → Stops […]
1. Classification of Tetracyclines Tetracyclines are classified based on duration of action: Type Drugs Half-life Short-acting Tetracycline, Oxytetracycline 6–8 hours Intermediate-acting Demeclocycline 12–16 hours Long-acting Doxycycline, Minocycline 16–24 hours 2. Mechanism of Action Inhibit protein synthesis by binding to […]
Overview Fluoroquinolones are a class of broad-spectrum bactericidal antibiotics. Synthetic derivatives of nalidixic acid (a quinolone). Common drugs: Ciprofloxacin, Ofloxacin, Levofloxacin, Moxifloxacin, Norfloxacin. Participate in GPAT MOCK TEST 
Mechanism of Action Fluoroquinolones inhibit bacterial DNA topoisomerases, which are enzymes […]
Antibiotic Drug Resistance Definition: The ability of bacteria to withstand the effects of an antibiotic that would normally kill them or inhibit their growth. Causes: Overuse or misuse of antibiotics Incomplete antibiotic courses Use of antibiotics in livestock and agriculture […]
Cephalosporins are classified into generations (1st to 5th) based on their antimicrobial spectrum and chronological development. Generation Examples Spectrum / Key Features 1st Generation Cefazolin, Cephalexin Good Gram-positive coverage (e.g., Staph, Strep); limited Gram-negative 2nd Generation Cefuroxime, Cefaclor, Cefoxitin […]
Classification of Penicillins Class Examples Spectrum / Features Natural Penicillins Penicillin G (IV), Penicillin V (oral) Narrow spectrum – mainly Gram-positive cocci, anaerobes, spirochetes (e.g., Treponema) Penicillinase-Resistant Penicillins Methicillin, Nafcillin, Oxacillin, Cloxacillin Resistant to staphylococcal beta-lactamase; used for MSSA Aminopenicillins […]
Beta-lactamase Inhibitors Pharmacology Definition: Beta-lactamase inhibitors are drugs that inhibit the action of beta-lactamase enzymes produced by bacteria. Mechanism of Action: They bind irreversibly to beta-lactamase enzymes, preventing these enzymes from breaking down beta-lactam antibiotics (e.g., penicillins). Classification of Beta-lactamase […]
Overview of Beta-Lactam Antibiotics Definition: A class of antibiotics containing a beta-lactam ring in their molecular structure, effective against a wide range of bacteria. Examples: Penicillins, cephalosporins, carbapenems, monobactams. Target: Primarily Gram-positive and some Gram-negative bacteria. Key Feature: Bactericidal (kill […]
Cotrimoxazole Overview Cotrimoxazole is a combination antibiotic medication that contains two active ingredients: sulfamethoxazole and trimethoprim. It’s commonly used to treat a variety of bacterial infections, such as urinary tract infections, respiratory infections (like bronchitis or pneumonia), and certain types […]
Pharmacokinetics Absorption: Well-absorbed orally from the gastrointestinal tract. Peak plasma levels: 2-6 hours post-dose. Food may delay absorption but doesn’t reduce total amount absorbed. Distribution: Widely distributed in body fluids (e.g., pleural, peritoneal, ocular fluids). Crosses placenta and blood-brain barrier […]