Aminoglycosides, Fluoroquinolones, Sulfonamides and Metronidazole Flashcards
Aminoglycosides
Streptomycin, Gentamicin (Garamycin), Kanamycin (Katrex), Tobramycin (Nebcin), Amikacin (Amikin), Neomycin
Aminoglycosides Spectrum of Action
Active against aerobic Gram- and some Gram+ bacteria
Aminoglycosides Mechanism of Action
Bactericidal (unique) but concentration-dependent, Bind to 16S rRNA of 30S subunit of ribosome to interfere with protein synthesis, Also cause misreading of mRNA (at low dose) producing abnormal proteins
Aminoglycosides Resistance
Plasmid-encoded production of transferase enzymes that induced metabolism of drug to inactive products (Enzymes - Acetyltransferases, Phosphotransferases and Adenyltransferases), Impaired entry of drug into cells by alteration of porins or other proteins needed for drug entry, Decrease binding of drug to 30S ribosome
Aminoglycoside + Penicillin
Enterococcal endocarditis
Aminoglycoside
Neutropenic fever (Pseudomonas) following chemotherapy, Medical emergency, Third choice adjuncts
Aminoglycoside + Beta lactam
Klebsiella, Staph. A, Pseudomonas, Meningitis due to Pseudomonas, Also for UTI
Neosporin (Neomycin, Polymyxin B, Bacitracin combination)
Topical skin infections, Sterilize bowel before bowel surgery
Paromomycin (Humatin)
Ameobiasis, Cestodiasis (Tapeworm infection) and Intestinal amebiasis, Hepatic coma, Leishmaniasis
Streptomycin
Bubonic plague, Tularemia, TB
Garamycin
Gram- rods, E.Coli, Pseudomonas, Salmonella, Shigella
Aminoglycosides Pharmacokinetics
Weak bases so may interact chemically with penicillins and cephalosporins if mixed in high concentration in parenteral administration (Chemical interaction), Administered IV as poor absorption from GI, Enters perilymph of inner ear (Toxic) also concentrate in renal cortex - Can be topically absorbed from burns and wounds when used in antibacterials
Aminoglycosides Adverse Effects
Renal damage, Eight nerve toxicity (Damage to vestibular or Cochlear sensitive hair cells) - Accumulate in endolymph and periplymph to damage hair cells - Can occur with fetal exposure in pregnancy; High conc. = Nondepolarizing neuromuscular blockade leading to respiratory paralysis (Compete with Ca++ at presynaptic sites resulting in release of Ach, fail of postsynaptic end plate to depolarize and muscle paralysis)
Fluoroquinolones
Ciprofloxacin (Cipro), Ofloxacin (Floxin), Levofloxacin (Levaquin), Sparfloxacin (Zagam)
Spectrum of Action
Active against aerobic Gram- bacteria, Some active VS Gram+ organisms; Levofloxacin and Sparfloxacin w/ good activity VS Gram+, Useful for URI by common pathogens like H.influenzae, M.cararrhails and Newer agents (Levofloxacin, Gatifloxacin, Trovofloxacin) active VS pneumonia (not Ciprofloxacin, Ofloxacin, Norfloxacin), Prophylaxis and treatment of neutropenic infections, Bone, joint and soft tissue infections, Ciprofloxacin was choice for post-exposure prophylaxis of inhalation anthrax terror attack (2001)