Categories: All - effects - absorption - resistance - interactions

by kathleen stephenson 5 years ago

217

Antibiotic part 2

Quinolones, also known as fluoroquinolones, are antibiotics with excellent oral absorption, though their efficacy can be diminished by antacids. They are effective against a range of gram-negative and some gram-positive bacteria.

Antibiotic part 2

Antibiotic part 2

Miscellaneous Antibiotics

Clindamycin (Cleocin) >Used for chronic bone infections, genitourinary infections, intraabdominal infections, other serious infections >may cause pseudomembranous colitis (also known as antibiotic associated colitis, Clostriiu difficile diarrhea, or c. diff infection) >Potential interaction with vecuronium
Linezolid (Zyvox) -New class: oxazolidinomes >used to treat vancomycin-resistant (Enterococcus faecium)VRE hospital acquired, and skin structure infections, including those with MRSA >may cause hyptension, serotonin syndrome if taken with selective serotonin reuptake inhibitors (SSRIs) and reactions if taken with tyramine-containing foods

Metronidazole (Flagyl) -used for aanaerobic organisms -Intraabdominal and gynecologic infections -Protozoal infections -Several drug interactions

Nitrofuantoin (macrodantin) -Primarily used for UTIs -use carefully if renal function is impaired -Drug concentrates in the urine -May cause fatal hepatotozicity

Quinupristin dalfopristin (synercid) -

Quinolones

-also called fluoroquinolones -Excellent oral absorption -Absorption reduced by antacids -Effective against gram-negative organisms and some gram positive organisms
Medications: -ciprofloxacin (Cipro) -norfloxacin (noroxin) -levofloxacin (Levaquin) -moxifloxacin (avelox) -Gemifloxacin (factive)

mechanism of action: -Bactericidal -Alter DNA of bacteria, causing death -Do not affect human DNA -Used to treat S. aureus, Serratia marcescens, and Mycobacterium fortuitum -Bacterial resistance to quinolone antibiotics: family that includes E. coli

Indications: -Gram negative bacteria such as Pseudomonas -Complicated urinary tract, respiratory, bone and joint, GI, skin, and sexually transmitted infections -Anthrax (ciprofloxacin)

Interactions: -oral quinolones: antacids, calcium, magnesium, iron, zinc preparations, or sucralfate -Patients need to take the interacting drugs at least 1 hour before or after taking quinolones. -Dairy products -Enteral tube feedings -Probenecid -Nitrofuraantoin -Oral anticoagulants

Adverse Effects: CNS; headache, dizziness, insomnia, depression, restlessness, convulsions GI: Nausea, vomiting, diarrhea, constipation, thrush, increased liver function study results, others Cardiac: Prolonged QT interval Integumentary: Rash, pruritus, urticaria, flushing Other: Ruptured tendons, tendonitis, fever chills, blurred vision, tinnitus

Aminoglycosides

-natural and semisyntheric -Produced from Steptomyces spp -Poor oral absorption; no oral forms (exception: neomycin) -very potent antibiotics with serious toxicities -Bactericidal; prevent protein synthesis -Kill mostly gram-negative bactericidal; prevent protein synthesis -Kill mostly gram-negative bacteria; some gram-positive bateria
Drugs: -Gentamicin -Neomycin (Neo-Fradin) -tobramycin (ToBI) -amikacin

Used to kill gram-negative bacteria, such as pseudomonas spp Escherichia coli, proteus spp, klebsiella spp, Serratia spp -often used in combination with other antibiotics for synergistic effects (beta- lactams or vancomycin) -Used for certain gram-positive infections that are resistanct to other antibiotics -Aminoglycosides are poorly absorbed through the GI tract and are given parenterally. -Exception: neomycin >given orally to decontaminate the GI tract before surgical procedures >Also used as an enema for this purpose >Used to treat hepatic encephalopathy

Adverse Effects -Cause serious toxicities >Nephrotoxicity (renal damage) >Ototoxicity (auditory impairment and vestibular impairment (8th cranial nerve) -Must monitor drug levels to prevent toxicities -Minimum inhibitory concentration (MIC) -Therapeutic drug monitoring -Ototoxicity and nephrotoxicity are the most significant -Headache -Paresthesia -Fever -Superinfections -Vertigo -Skin rash -Dizziness

Therapeutic Drug Monitoring -Serum levels measured to prevent toxicity -Serum level needs to be at least eight times higher than the MIC -Time dependent killing -Concentration dependent killing -Peak: highest drug levels for once daily regimens -Trough: lowest to ensure adequate renal clearance of the drug and avoid toxicity -Postantibiotic effects -Resistance -Drug interactions