Cephalosporins and Penicillins Overview

Cephalosporins

• Multiple generations of cephalosporins exist: First, Second, Third, and Fourth
• First generation cephalosporins are most effective against gram-positive organisms, like staphylococci and streptococci
• Second generation are more potent, resistant to beta-lactamase, and have a broader spectrum against gram-negative organisms
• Third generation have an even broader spectrum against gram-negative bacteria than the second generation
• Fourth generation effective against organisms resistant to earlier cephalosporins

Penicillins and Penicillinase-Resistant Antibiotics

• One of the first antibiotics used clinically, major antibacterial drug
• Major adverse reactions are hypersensitivity reactions
• Anaphylactic reactions are a concern, with symptoms like bronchospasm, wheezing, fainting, and chest tightness
• Other hypersensitivity reactions include serum sickness and skin rashes
• Oral penicillins can cause adverse GI reactions, including oral candidiasis, nausea, vomiting, and diarrhea
• Probiotics like yogurt or buttermilk can help normalize GI flora

Sulfonamides

• Can cause Steven Johnson syndrome, a rare and serious disorder of the skin and mucous membranes. It begins with flu-like symptoms and progresses to a painful rash that spreads and blisters.

Nitrofurantoin

• Used to treat acute and chronic urinary tract infections, affecting both gram-positive and gram-negative organisms
• Can cause hypersensitivity reactions, including anaphylaxis, skin rashes, pruritus, and reactions involving the lungs, blood, and liver

Tetracyclines

• Cross the placenta and pass into breast milk
• Contraindicated in pregnancy, lactation, and children under 8 years old
• Contraindicated in individuals with known allergies to tetracyclines or tartrazine, renal or hepatic dysfunction, and those taking penicillin G or oral contraceptives
• Can cause superinfection, hepatotoxicity, GI disturbance, photosensitivity, renal toxicity, tooth discoloration, and impaired fetal skeletal development

Clindamycin

• Primarily bacteriostatic at therapeutic concentrations
• Potent against aerobic gram-positive organisms, including staphylococci, streptococci (except Enterococcus faecalis), and pneumococci
• Used to treat anaerobic intra-abdominal, pleural, or pulmonary infections caused by Bacteroides fragilis.
• Monitor patients for signs and symptoms of Clostridium difficile-Associated Diarrhea/pseudomembranous colitis

Macrolides

• Can cause QT interval prolongation on Cardiac Monitor, due to blockage of ion channels causing delayed repolarization
• Check ECG monitor/Cardiac monitor regularly

Vancomycin

• Absorbed poorly from GI tract, must be administered intravenously for systemic infections
• Increases risk of nephrotoxicity and ototoxicity when used with aminoglycoside, amphotericin B, bacitracin, and colistin
• Only administered intravenously, intramuscular administration is not recommended due to pain and tissue necrosis
• Can cause ototoxicity and nephrotoxicity
• Rapid intravenous infusion can lead to severe hypotensive reaction and erythematous rash/flushing (RED MAN SYNDROME). Slow down or regulate the infusion if this occurs.

Antimycobacteria/ Antitb Drugs

• Used in combination to treat mycobacterial infections, specifically Mycobacterium tuberculosis
• Treatment regimens involve two or more drugs to prevent bacterial resistance and require prolonged treatment (6-12 months)
• Used for treatment and prevention of tuberculosis
• Goal of treatment: eliminate infection, prevent relapse, prevent drug-resistant organisms, control symptoms, and prevent progression of the disease
• Isoniazid (Laniazid) is the primary agent for treatment and prophylaxis
• Rifampin (Rifadin) is a first-line drug for pulmonary tuberculosis

This quiz explores the classifications and key characteristics of cephalosporins and penicillins. It covers the generations of cephalosporins, their effectiveness against different bacteria, and the adverse reactions associated with penicillins. Test your knowledge on these crucial antibiotics and their clinical implications.