Antimicrobials Flashcards
Which is dose-related, having a hypersensitive reaction or having issues with toxicity?
Toxicity has to do with dose (too much)
Hypersensitive (allergic) reaction does not depend on dose
When are surgical prophylactic antibiotics given?
Less than one hour before surgery
Is ampicillin or amoxicillin more likely to be given by mouth? Which of these drugs has a higher incidence of skin rash?
Amoxicillin is given by mouth more because it is more efficiently absorbed from the GI tract
Ampicillin has a highest incidence of skin rash among penicillins, used for H flu and E coli
**Note: these are both broad-spectrum, second generation penicillins
Are penicillins bactericidal or bacteriostatic? What organisms do they work against? How is it excreted?
Bactericidal
Penicillin against pneumococcal, meningococcal, streptococcal (gram pos), second generation against gram neg
Renal excretion
Adverse reactions to penicillins?
Hypersensitivity (more than the other antimicrobials)
Cross sensitivity between penicillin and cephalosporins (this is due to the beta-lactam ring in both)
Cephalosporin: broad or narrow spectrum? bacteriostatic or bactericidal? How is it excreted?
Broad spectrum
Bactericidal
Renal excretion
3 generations: 1-cefazolin (ancef), 2-cefoxitin, 3-cefotaxime
Adverse reactions of cephalosporins?
Allergic reactions (rash) Cross sensitivity between cephalosporins and penicillin
Why are cephalosporins used in orthopedic surgery?
They penetrate into the joints
Are aminoglycosides bactericidal/ bacteriostatic? Which organisms are they effective against? How is it excreted?
Bacteriocidal
Gram neg bacteria.. Narrow!
Renal excretion
What are side effects of aminoglycosides?
Ototoxicity: irreversible vestibular/cochlear destruction over time
Nephrotoxicity: reversible, accumulation in renal cortex can cause tubular necrosis (neomycin #1 nephrotoxic, monitor BUN/creatinine)
Skeletal muscle weakness: inhibit ACh release (myasthenia gravis are sensitive), also issue with reversing muscle relaxant, calcium can help
Prolongs neuromuscular blockade: potentiated, reappears in PACU
Why should use of Streptomycin and Kanamycin (aminoglycosides) be limited?
Why should plasma concentrations of Gentamycin by monitored?
Increased occurrence of vestibular damage with Streptomycin and Kanamycin
Gentamycin becomes toxic over 9 mcg/mL
Which aminoglycoside is used for hepatic comas? Hint: this is also the aminoglycoside that is most nephrotoxic.
Neomycin
Tetracyclines: Bactericidal or bacteriostatic? Uses? Where excreted?
Bacteriostatic
Used for acne treatment (decreases fatty acid content of sebum)
Excreted in urine and bile
Side effects of tetracyclines?
Permanent discoloration of teeth
Phototoxicity
Macrolides (Erythromycin/Zithromax): bacteriostatic or bactericidal? Broad or narrow spectrum? How is it metabolized/excreted?
Can be bacteriostatic or bacteriocidal (by inhibiting protein synthesis)
Narrow spectrum against gram +
Metabolized by cytochrome P-450 (smooth ER of liver), excreted by bile (so no need to alter dose for renal disease patients)
Macrolides (Erythromycin) adverse effects?
GI intolerance: N/V
increased gastric emptying
QT effects: prolongs cardiac repolarization, increased incidence of torsades de pointes
Thrombophlebitis
Lindomycins (Clindamycin): bacteriostatic/ bactericidal? Uses? Should dose be decreased for renal or liver disease?
Bacteriostatic
Used for serious infections in GI tract or female genital tract
Decrease dose with severe liver disease (metabolized in liver), elimination is only slightly prolonged with renal disease so this doesn’t require dose adjustment
Clindamycin side effects?
Pseudomembranous colitis (severe diarrhea), when patient gets diarrhea, this med should be discontinued Pre and post junctional effects at neuromuscular junction, not antagonized with anticholinesterases or calcium (not effective when reversing neuromuscular blocker), extended time of neuromuscular blockade
Vancomycin: bactericidal/bacteriostatic? What organisms is it effective against? Excretion?
Bactericidal
Effective against gram positive bacteria, staph infections, streptococcal/ enterococcal endocarditis.. Narrow!
Drug of choice against MRSA
Renal excretion, (extremely prolonged elimination with renal failure, check vanco levels)
Vancomycin surgeries?
Dose?
cardiac procedures
Orthopedic procedures with prosthetics
CSF and shunt infections
Dose: 10-15 mg/kg over 60 min (usually 1g/h), 1 gram mixed in 250 mL
Which two drugs are used in many surgical procedures when a patient has a beta-lactam allergy?
Clindamycin or vancomycin
Vancomycin side effects?
Rapid infusion can cause profound hypotension/ cardiac arrest
Red man syndrome (histamine release)
Ototoxicity
Nephrotoxicity
Return of neuromuscular blockade noted rarely
Sulfonamides: bacteriostatic/ bactericidal? Uses? Metabolism/excretion?
Bacteriostatic
Used for UTIs
Hepatic metabolism
Renal excretion
Sulfonamides side effects?
Rash to anaphylaxis Drug fever Hepatotoxicity Acute hemolytic anemia Increased effect of po anticoagulants
Polymyxin B and Colistimethate: Bacteriostatic/ bactericidal? Uses? Elimination?
Bactericidal
Effective for gram negative bacteria: UTI’s, infections of skin, mucous membranes, eyes, ears.. Narrow!
Eliminated by kidneys (accumulation in renal failure)
Polymyxin B and Colistimethate: side effects?
Most potent antimicrobial at the neuromuscular junction (can produce skeletal muscle wekaness like a nondepolarizing neuromuscular blocker, neostigmine or calcium don’t antagonize this drug)
Highly nephrotoxic
Metronidazole (flagyl): bacteriostatic/ bactericidal? What organism does it work against? Uses?
Bactericidal
Anaerobic Gram negative bacilli
Useful for CNS, abdominal, pelvic, and pseudomembranous colitis
Fluoroquinolones (Ciprofloxacin, Moxifloxacin): broad or narrow spectrum? Bacteriostatic/ bactericidal? Uses? Excretion?
Broad spectrum, enteric against gram neg bacilli
Bactericidal
Used for GI/GU infections, Ciprofloxacin is useful in treating bone, soft tissue, and respiratory infections
Excreted by renal, can inhibit P450, E1/2t is 3-8 hours
Fluoroquinolones side effects?
Minimal (this is why it is used for GI/GU infections)
Rifampin: Bacteriostatic/ bactericidal? Uses? Which organisms does it fight against? Excreted?
Bactericidal for mycobacteria TB drug Gram positive and some gram negative.. BROAD spectrum Excreted in bile/urine Note: fat soluble, travels to CNS
Rifampin side effects?
Infrequent, in high doses: thrombocytopenia, aneia, hepatitis, fatigue, numbness, skeletal muscle weekness, induces P450 which will metabolism drugs (opioids, NM blockers, warfarin) quicker
Amphotericin B: what class? Given IV or po? How is it excreted?
Antifungal
Given IV
Slow renal excretion (impairs functioning in 80% of patients, monitor BUN/creatinine)
Antifungal side effects?
Fever, chills, dyspnea, hypotension during infusion Impaired hepatic and renal function Allergic reaction Seizure Anemia, thrombocytopenia
Are viruses intracellular or extracellular parasites? Why does this make it difficult to treat?
Intracellular parasites, hard to treat because you must kill your own cells to kill the virus
Viruses are composed of a nucleic acid core surrounded by a protein containing outer coat, genome has RNA or DNA, but never both
Uses for Acylovir and valacyclovir?
Antiviral for herpes viruses
Uses for Vidarabine?
Cytomegalic inclusion disease, herpes simplex encephalitis
Mutagenic and carcinogenic
Uses for famciclovir?
Acute herpes zoster
Uses for Ganciclovir?
Cytomegalovirus disease
Caution: hematologic toxicity
Uses for Amantadine?
Influenza A or parkinsons
How do Interferons work, what viruses can they be used for?
They bind to receptors on host cell to induce the production of enzymes that will inhibit replication, this will degrade viral mRNA. They also enhance tumoricidal activities of macrophages
Used for chronic Hep B, Hep C
Interferon side effects?
Flu like symptoms, depression, irritability, decreased concentration
Hematologic toxicity (leukopenia, get a CDC)
Development of autoimmune conditions
Rashes, alopecia
Changes in CV, thyroid, hepatic functioning
What are some HIV antivirals?
NRTIs: are imposters, the look like fake human cells
NNRTIs: inhibit enzyme function of virus
(Nuclease/Non-nuclease reverse transcriptase inhibitors)
Protease inhibitors: bind to HIV protease
What are side effects of HIV antivirals?
Many, varied responses Pancreatitis, hepatotoxicity, lactic acidosis, fat redistribution, increased cholesterol and TAGs, hypersensitivity Protease inhibitors (especially Ritonavir) inhibit P450 system (prolonging action of many drugs)
Which antimicrobials are bacterioSTATIC?
SECT.. Sulfonamides Erythromycin (macrolides).. both static and cidal Clindamycin Tetracycline
Which antimicrobials prolong neuromuscular blockade?
PACC.. Polymyxin B Aminoglycosides Clindamycin Colimethate
