Antibiotics Affecting the Bacterial Cell Wall (Pharmacology Ch 44)

Question 1

Bactericidal antibiotics

Answer 1

• antibiotics that affect the cell wall
  1) penicillins
  2) cephalosporins
  3) carbapenems
  4) monobactams

Question 2

Penicillins

Answer 2

• destroy bacteria by weakening the bacterial cell wall

- select prototype = penicillin G potassium (Pfizerpen)–narrow-spectrum med for IM or IV use

Question 3

Other penicillin medications

Answer 3

• narrow-spectrum
  1) penicillin G benzathine (Bicillin)–IM use
  2) penicillin V (Veetids)–oral use
• broad-spectrum
  1) amoxicillin-clavulanate (Augmentin)–oral use
  2) ampicillin (Principen)–oral or IV use
• antistaphylococcal
  1) nafcillin (Unipen)–IM or IV use
• antipseudomonas
  1) ticarcillin-clavulanate (Timentin)–IV use
  2) piperacillin tazobactam (Zosyn)–IV use

Question 4

Penicillins: therapeutic uses

Answer 4

1) med of choice for gram-positive cocci such as Streptococcus pneumoniae (pneumonia and meningitis), Streptococcus viridans (infectious endocarditis), and Streptococcus pyogenes (pharyngitis)
2) med of 1st choice for meningitis caused by gram-negative cocci Neisseria meningitides
3) med of choice for treatment of syphilis caused y Spirochete treponema pallidum
4) extended-spectrum penicillin (piperacillin, ticarcillin) is effective against Pseudomonas aeruginosa, Enterobacter species, Proteus, Bacteroides fragilis, and Klebsiella
5) used as prophylaxis against bacterial endocarditis in at-risk clients prior to dental and other procedures

Question 5

Penicillins:

adverse effects and nursing interventions/client education

Answer 5

1) allergies/anaphylaxis – interview clients for prior allergy; advise clients to wear allergy ID bracelet; observe client for 30 min following administration of parenteral penicillin
2) renal impairment – monitor kidney function; monitor I&O
3) hyperkalemia/dysrhythmias (high doses of penicillin G potassium) and hypernatremia (IV ticarcillin) – monitor cardiac status and electrolyte levels

Question 6

Penicillins: contraindications/precautions

Answer 6

1) contraindicated in clients w/ severe hx of allergies to penicillin, cephalosporin, and/or imipenem
2) use cautiously in clients who have or are @ risk for kidney dysfunction (acutely ill clients, older adults, young children)
3) clients allergic to one penicillin should be considered cross-allergic to other penicillins and at risk for cross allergy to cephalosporin

Question 7

Penicillins: interactions

Answer 7

1) penicillin inactivates aminoglycosides when mixed in the same IV solution
2) probenecid (Probalan) delays excretion of penicillin

Question 8

Penicillins: nursing administration

Answer 8

1) instruct clients that penicillin V, amoxicillin, and amoxicillin-clavulanate may be taken w/ meals. All others should be taken w/ full glass of water 1 hr before meals or 2 hr after
2) instruct clients to report signs of allergic response (skin rash, itching, and/or hives)
3) IM injection should be performed cautiously to avoid injection into a nerve or artery
4) advise clients to complete entire course of therapy regardless of presence of symptoms

Question 9

Cephalosporins

Answer 9

• beta-lactam antibiotics, similar to penicillins, that destroy bacterial cell walls causing destruction of micro-organisms
• select prototype = cephalexin (Keflex)–1st generation

Question 10

Cephalosporins: other medications

Answer 10

• 1st generation: cefazolin (Ancef)
• 2nd generation: cefaclor (Ceclor), cefotetan (Cefotan)
• 3rd generation: ceftriaxone (Rocephin), cefotaxime (Claforan)
• 4th generation: cefepime (Maxipime)

Question 11

Cephalosporins are grouped into 4 generations. Each subsequent generation is:

Answer 11

• more likely to reach cerbrospinal fluid
• less likely to be destroyed by beta-lactamase
• more effective against gram-negative organisms and anaerobes

Question 12

Cephalosporins: therapeutic uses

Answer 12

-broad-spectrum bactericidal medications with a high therapeutic index that treat UTIs, postoperative infections, pelvic infections, and meningitis.

Question 13

Cephalosporins:

adverse effects and nursing interventions/client education

Answer 13

1) allergic/hypersensitivity/anaphylaxis–if indications of allergy appear (urticaria, rash, hypotension, and/or dyspnea) stop cephalosporin immediately and notify provider.
2) possible cross-sensitivity to penicillin–question client carefully regarding past hx of allergy to penicillin or other cephalosporin, and notify provider if present
3) bleeding tendencies w/ use of cefotetan and ceftriaxone–avoid use in clients who have bleeding disorders and those taking anticoagulants; observe clients for signs of bleeding; monitor prothrombin time and bleeding time. Abnormal levels can require discontinuation of medication; administer parenteral vitamin K
4) thrombophlebitis w/ IV infusion–rotate injection sites; administer as a diluted intermittent infusion or, if a bolus dose is prescribed, administer slowly over 3-5 min and in a dilute solution
5) pain w/ IM injection–administer IM injection deep in large muscle mass
6) antibiotic-associated pseudomembranous colitis–observe clients for diarrhea and notify provider; medication should be discontinued

Question 14

Cephalosporins: contraindications/precautions

Answer 14

1) should not be given to clients w/ a hx of severe allergic reaction to penicillins
2) use cautiously in clients who have renal impairment or bleeding tendencies

Question 15

Cephalosporins: interactions

Answer 15

1) disulfiram reaction (intolerance to alcohol) occurs w/ combined use of cefotetan, cefazolin, cefoperazone, and alcohol–instruct clients not to consume alcohol while taking these cephalosporins
2) probenecid delays renal excretion–monitor I&O

Question 16

Carbapenems

Answer 16

• beta-lactam antibiotics that destroy bacterial cell walls, causing destruction of micro-organisms
• select prototype = imipenem-cilastatin (Primaxin)

Question 17

Carbapenems: other medications

Answer 17

-meropenem (Merrem IV)

Question 18

Carbapenems: therapeutic uses

Answer 18

1) broad antimicrobial spectrum is effective for serious infections such as pneumonia, peritonitis, and UTIs caused by gram-positive cocci, gram-negative cocci, and anaerobic bacteria
2) resistance develops when imipenem is used alone to treat Pseudomonas aeruginosa. A combination of antipseudomonal medications should be used to treat this micro-organism

Question 19

Carbapenems:

adverse effects and nursing interventions/client education

Answer 19

1) allergy/hypersensitivity–monitor clients for indications of allergic reactions, such as rashes or pruritus
2) possible cross-sensitivity to penicillin or cephalosporins–question clients carefully regarding past hx of allergy to a penicillin or other cephalosporin and notify provider if present
3) GI symptoms (nausea, vomiting, diarrhea)–observe clients for manifestations and notify the provider if they occur; monitor I&O
4) suprainfection–monitor for indications of colitis (diarrhea, oral thrush, and/or vaginal yeast infection)

Question 20

Carbapenems: interactions

Answer 20

-imipenem-cilastatin can reduce blood levels of valproic acid (Depakote). Breakthrough seizures are possible.–avoid using together. If concurrent use is unavoidable, monitor for increased seizure activity.

Question 21

Carbapenems: contraindications/precautions

Answer 21

1) imipenem-cilastatin is a pregnancy risk category C medication
2) use cautiously in clients who have renal impairment

Question 22

Other inhibitors

Answer 22

• this group of antibiotics destroys bacterial cell walls, causing destruction of micro-organisms
• select prototype medications:
  1) vancomycin (Vancocin)
  2) aztreonam (Azactam)–[classified as a monobactam]
  3) fosfomycin (Monurol)

Question 23

Other inhibitors: therapeutic uses

Answer 23

They are antimicrobials of choice for:

1) serious infections caused by methicillin-resistant Staphylococcus aureus, E. coli, or Staphylococcus epidermidis AND
2) antibiotic-associated pseudomembranous colitis caused by Clostridium difficile.

Question 24

Other inhibitors:

adverse effects and nursing interventions/client education

Answer 24

1) ototoxicity–assess for indications of hearing loss; instruct clients to notify the provider if changes in hearing acuity develop; monitor vancomycin levels
2) infusion reactions (rashes, flushing, tachycardia, and hypotension, sometimes called “red man syndrome”)–administer vancomycin slowly over 60 min
3) IV injection site thrombophlebitis–rotate injection sites; monitor the infusion site for redness, swelling, and inflammation
4) renal toxicity–monitor I&O and kidney function tests; monitor vancomycin trough levels

Question 25

Other inhibitors: interactions

Answer 25

1) increased risk for ototoxicity when vancomycin is used concurrently w/ another medication that also produces ototoxicity (loop diuretics and aminoglycoside antibiotics)–assess for hearing loss

Question 26

Other inhibitors: contraindications/precautions

Answer 26

1) contraindicated for clients who have allergy to corn/corn products or previous allergy to vancomycin
2) use cautiously in clients who have renal impairment, hearing impairment, or older adults