2025 – PAGE 297 – INFECTIOUS DISEASES
CEPHALOSPORINS
- FIRST GENERATION CEPHALOSPORINS: Cephalexin (Keflex – PO) and Cefazolin (Ancef – IV). These provide good activity against Staph and Strep but no activity against MRSA. In addition, there is good activity against some gram negatives (Proteus, E. coli, and Klebsiella).
- MNEMONIC: Coverage against PEcK.
- SECOND GENERATION CEPHALOSPORINS: Cefaclor, Cefuroxime, Cefotetan, and Cefoxitin. These are no good for gram positives but provide BETTER gram-negative coverage. They cover the above organisms and Haemophilus influenza, Enterobacter, and Neisseria.
- MNEMONIC: Coverage against HEN PEcK
- MNEMONIC: There are no “T’s” near the “F” of these names, except for cefoTeTan. Imagine two big mountains (or lady parts) called the grand TeTons to help remind you that it is a 2nd generation.
- THIRD GENERATION CEPHALOSPORINS: Ceftriaxone, Cefotaxime, Ceftazidime, and Cefpodoxime. These are also not very good for gram-positive coverage but provide even BETTER gram-negative coverage. They are good for hospital-acquired gram-negative infections and great for CNS infections, which is why we give CEFTRIAXONE for meningitis. Ceftazidime is a great drug for Pseudomonas.
(DOUBLE TAKE) PEARL: Ceftriaxone is still great for Streptococcus. When treating for meningitis, also give Vancomycin. The vancomycin is NOT being given for Staph aureus coverage. It’s being given for possible Strep that is RESISTANT to ceftriaxone!
-
- MNEMONIC: Most THREE generation drugs have a “T” within THREE letters of the “F.” cefpodoXime is the X-cepTion.
- MNEMONIC: cefTAZadime is good for pseudoMON Think of TAZ-MON-ian devil
- MNEMONIC IMAGE: www.pbrlinks.com/CEPHALOSPORINS1
- FOURTH GENERATION CEPHALOSPORINS: Cefepime. Extended spectrum agent with gram-positive coverage that’s just as good as the FIRST generation’s. Good CNS penetration and broader gram-negative coverage. More resistant to beta-lactamases.
MACROLIDES
Macrolides include azithromycin, clarithromycin, erythromycin… anything with a –THROMYCIN. A common side effect is increased GI motility.
MNEMONIC: Ever use erythromycin for diabetic gastroparesis? Maybe in med school?
CARBAPENEMS
Imipenem could be seen on the exam. Use carbapenems for extended-spectrum beta-lactamase (ESBL) producing organisms. EnteroBACTER (a gram-negative organism) is a common one.
ALBENDAZOLE & PYRANTEL PAMOATE
Albendazole and pyrantel pamoate are for WORM infections.
PEARL: For Enterobius (AKA PINWORMS), give the first dose and then repeat the dose after two weeks. For most worm infections, treatment requires multiple doses.
METRONIDAZOLE
Metronidazole is active against parasites and anaerobic infections. It is often used for intra-abdominal infections. Some of the commonly treated organism include Giardia, Entamoeba, Trichomonas, Bacteroides, Clostridium, and Gardnerella.
MNEMONIC: Commonly treated organisms = GET BCG! There is a women’s clothing line called BCG. There’s also a consulting firm called BCG. Imagine a woman traveling on an underground METRO to go and GET BCG clothing/consulting! It’s stuffy underground, and it feels like there’s not much air (anaerobes).