Drugs that weaken the cell wall II: Cephalosporins and Vancomycin Flashcards
state the major differences in each of the five generations of cephalosporins.
generation 1: highly active against gram positive bacteria
generation 2: highly active against gram negative bacteria
generation 3: broad spectrum antimicrobial
generation 4: highly resistant to beta-lactamase
generation 5: broad spectrum but also effective against MRSA.
describe the absorption and the adverse effects of cephalosporin.
because of impaired GI absorption, many cephalosporins must be administered parenterally, that is IM or IV.
adverse effects:
allergic reactions: hypersensitivity reactions–maculopapular rash that develops after the onset of treatment is most common. Severe reactions are rare but if sx/sx start coming up (eg bronchospasm, anaphylaxis), dc IMMEDIATELY. ALSO NO GIVING CEPHALSPORINS TO PATIENTS WITH A HX OF A SEVERE REACTION TO PENICILLINS D/T POTENTIAL FOR FATAL ANAPHYALAXIS.
bleeding:
two cephalosporins can cause bleeding tendencies: cefotetan and ceftriaxone. patient should be monitored for pro-thrombin time, bleeding time or both along with signs of bleeding. if bleeding develops the cephalosporin should be withdrawn. caution should be exercised during concurrent use of anticoagulants or thrombolytic agents. Use NSAIDs with care d/t antiplatelet effects. Also caution in patients with hx of bleeding disorders.
thrombophlebitis: may develop during IV infusion, can be minimized by rotating the infusion site and by administering cephalosporins slowly and in dilute solution. if phlebitis develops, the infusion site should be changed.
hemolytic anemia: rare
if develops, cephalosporin should be discontinued and blood transfusions given as needed.
other: can cause pain at sites of injection,
can cause pseudomembranous colitis with C diff–if this happens dc immediately and give oral vancomycin if necessary.
with cefditoren–two concerns
avoid with patients with a milk-protein hypersecretion and contraindicated with patients with carnitine deficiency.
list symptoms for C diff infection, along with risk factors and efforts to control
symptoms: watery diarreha, belly pain, fever, pseudomembranous colitis, characterized by patches of severe inflammation and purulent drainage.
risk factors: treatment with antibiotics, especially among older adults, Gi surgery, serious illness, prolonged hospitalization, immunosuppression as a result of treatment of another disease.
efforts to control: use antibiotics judiciously, isolate C diff patients, wear gloves and a gown if entering C diff room and wash hands after contact with a patient with C diff, use disposable rectal thermometers, decontaminate surfaces with a cholrine-containing clean agent.
List important points on patient teaching for the cephalosporins and vancomycin.
Cephalosporins:
oral admin: advise patients to take oral cephalosporins with food if gastric upset occurs. instruct patients to refrigerate oral suspensions. instruct patients to complete the prescribed course even though they may feel better before it’s over.
instruct the patient to report any signs of allergy (skin rash, itching, hives).
advise patients about alcohol intolerance and instruct them not to drink alcoholic beverages.
vancomycin:
oral: instruct patients to complete the prescribed course even though they may feel better.
Differentiate vancomycin flushing syndrome or infusion reaction from anaphylaxis.
VFS consists of a pruritic, erythematous rash of the face, neck, and upper torso, which may also involve the extremities, though to a lesser degree. VFS is caused by vancomycin through the direct and non-immune-mediated release of histamine from mast cells and basophils. The amount of histamine release is generally related to the dosage of vancomycin infused and the rate of infusion. VFS is generally associated with more rapid infusion rates but can be seen following slower infusion rates and after several days of transfusion.
symptoms of VFS include: Erythematous rash on the face, neck, and upper torso Nausea, vomiting Pruritis Hypotension Fever, chills Weakness, dizziness Chest or back pain, trunk muscle spasms Angioedema Tachycardia Rash on the extremities may occur but is typically less severe than the rash on the face, neck, and upper torso
anaphylactic reaction, which is an immunoglobulin E-mediated response and caused larngyoedema, hives, and etc.
Using ceftriaxone (Rocephin) as an example of 3rd generation, state mechanism of action, therapeutic uses, adverse effects.
mechanism of action: bind to penicillin-binding proteins and disrupt cell wall synthesis along with activating autolysins and thereby causing death by lysis to the cell wall.
therapeutic uses:
meningitis caused by enteric, gram negative bacilli, nosocomial infections,
two agents (ceftriaxone and cefotaxime): are drugs of choice for infections caused by gonorrhea, influenza H, proteus, salmonella, klebsiella, and Serratia, and these drugs are also effects against meningitis caused by streptococcus pneumoniae (g +)
AE’s: allergic reactions, bleedings, thrombophlebitis, hemolytic anemia, pain at site of injection, pseudomembranous colitis, etc.
Regarding carbapenems (imipenem & meropenem), state mechanism of action, how it is given, therapeutic uses, adverse effects.
MOA: binds to PBPs causing weakening of the bacterial cell wall with subsequent cell lysis and death.
therapeutic uses: used widely, effective for serious infections caused by gram positive cocci, gram negative cocci, and anaerobic bacteria.
adverse effects: generally well tolerated. GI effects (nausea, vomiting diarrhea) most common. Superinfections and seizures rare. Hypersensitivity reactions have occurred.
how it is given: formulated in 1:1 fixed dosage combinations with cilastatin. marketed under the brand name parimaxin. supplied in powdered form and reconstituted according to manufacturer’s instructions.
Regarding vancomycin, describe route of absorption, therapeutic uses, and major adverse effects (some content is in small print).
route of absorptions: poor absorption from GI tract, so given parenterally by slow IV infusion. Oral admin only for infections of the intestine.
therapeutic uses: should be reserved for serious infections. drug of choice for infections caused by MRSA or staph epidermidis, drug of choice for severe CDI (not mild), also an alternative to cephalosporins and penicillin’s to teat severe infections in patients allergic to beta-lactam antibiotics.
major adverse effects:
renal failure–dose related risk, minimize by giving no more than needed
ototoxicity-rare and reversible
red man syndrome-flushing, rash, puritis, hives, tachycardia, hypotension, d/t rapid infusion, minimize by slowly infusing (over 60 mins
thrombophlebitis-minimize by administering in dilute solution and changing infusion site frequently
immune-mediated thrombocytopenia (rare)
