1 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Chapter 29 PENICILLINS AND CEPHALOSPORINS

2 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Infection Pathophysiology  Disease-producing organisms  Bacteria Gram +, gram –, viruses, fungi Bacterial cell wall differs in structure  Bacilli: elongated, or rod-shaped  Cocci: spherical Single-cell microorganisms  Viruses Smallest pathogen, toughest  Fungi Yeasts or mold, infect skin or subcutaneous tissue

3 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Antibacterials  Antibiotics  Bacteriostatic drugs Inhibit growth of bacteria  Bactericidal drugs Kill bacteria

4 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Antibacterials (cont’d)  Pharmacodynamics  Inhibition of bacterial cell wall synthesis  Alteration of membrane permeability  Inhibition of protein synthesis  Inhibition of synthesis of bacterial RNA and DNA  Interference with metabolism within the cell

5 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Antibacterials (cont’d)  Body defenses  Age  Nutrition  Immunoglobulins  Circulation, WBCs  Organ function  Resistance to antibacterials  Natural or inherent resistance  Acquired resistance  Nosocomial infections  Cross-resistance

6 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Antibacterials (cont’d)  Antibiotic combinations  Effects Additive: effect is doubled Potentiative: one potentiates effect of other Antagonistic: if one bactericidal and one bacteriostatic, desired effect is diminished

7 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Antibacterials (cont’d)  General adverse reactions  Mild allergic reaction Rash, pruritus, hives  Severe allergy: anaphylactic shock Bronchospasm, laryngeal edema Vascular collapse, cardiac arrest  Treatment Antihistamine Epinephrine Bronchodilator

8 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Antibacterials (cont’d)  General adverse reactions  Superinfection Secondary infection: normal flora killed Sites: mouth, skin, respiratory tract, vagina, intestines Usually occurs when treated more than 1 week  Organ toxicity Ear Liver Kidney

9 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Antibacterials (cont’d)  Spectrum  Narrow spectrum Primarily effective against one bacteria type Examples: penicillin, erythromycin  Broad spectrum Effective against gram + and gram – Examples: tetracycline, cephalosporins

10 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Penicillins  Structure of penicillins  Beta-lactam ring  Basic penicillins  Introduced to kill Staphyloccus  Inhibit bacterial cell wall synthesis  Narrow-spectrum  Examples: penicillin G Na/K, penicillin G procaine, penicillin V

11 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Penicillins (cont’d)  Broad-spectrum penicillins  Against gram + and gram – Escherichia coli Salmonella Influenzae  Bactericidal  Also known as aminopenicillins Examples:  Amoxicillin (Amoxil)  Ampicillin (Omnipen)

12 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Penicillins (cont’d)  Penicillinase-resistant penicillins  Against most gram + Staphylococcus  Bactericidal  Also known as antistaphylococcal penicillins Examples: dicloxacillin (Dynapen)

13 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Penicillins (cont’d)  Extended-spectrum penicillins  Against gram – Pseudomonas aeruginosa, Proteus, Klebsiella pneumoniae  Treat bone, joint, skin, soft tissue, respiratory tract, urinary tract infections  Bactericidal  Antipseudomonal penicillins Examples:  Piperacillin (Pipracil)  Ticarcillin (Ticar)  Carbenicillin (Geopen)

14 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Penicillins (cont’d)  Beta-lactamase inhibitors  Not given alone Combined with penicillinase-sensitive penicillin  Examples: Clavulanic acid Sulbactam Tazobactam Ticarcillin

15 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Penicillins (cont’d)  Beta-lactamase inhibitors  Inhibits bacterial beta-lactamase enzyme Amoxicillin-clavulanate (Augmentin)  Given orally  Combination intensifies effect of amoxicillin Piperacillin-tazabactam (Zosyn) Ticarcillin-clavulanate (Timentin) Ampicillin-sulbactam (Unasyn)  Given parenterally  Combination extends spectrum

16 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Penicillins (cont’d)  Nursing interventions  Check culture and sensitivity before drugs are given.  Monitor for bleeding.  Monitor closely during first dose.  Increase fluids.  Take 1 hour before or 2 hours after meals.  Check for superinfection.  Consider safety issues.

17 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Cephalosporins  Cephalosporins  Beta-lactam structure  Semi-synthetic  Inhibit bacterial cell-wall synthesis  Bactericidal  Treat Respiratory, urinary, skin, bone, joint, and genital infections

18 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Cephalosporins (cont’d)  Generations of cephalosporins  First-generation Cephalexin (Keflex), cefazolin (Kefzol)  Second-generation Cefaclor (Ceclor), cefoxitin (Mefoxin)  Third-generation Cefoperazone (Cefobid), ceftriaxone (Rocephin)  Fourth-generation Cefepime (Maxipime)

19 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Cephalosporins (cont’d)  Generations of cephalosporins  First-generation Gram + bacteria: E. coli, Klebsiella  Second-generation Gram + and –: Neisseria gonorrhorae,Haemophilus influenzae, Neisseria meningitidis  Third-generation Gram + and –: Psuedomonas aeruginosa  Fourth-generation Gram + and –: Streptococci, staphylococci

20 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Cephalosporins (cont’d)  Pharmacokinetics  Some oral; others IM, IV  Side effects/adverse reactions  Weakness  Pruritus  GI distress  With high doses Increased bleeding Seizures Nephrotoxicity

21 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Cephalosporins (cont’d)  Drug interactions  Alcohol: may cause flushing, dizziness, HA, nausea, vomiting, muscular cramps  Uricosurics: decrease cephalosporin excretion  Nursing interventions  Assess for allergy.  Perform C & S before therapy.  Assess renal and liver function.  Administer IV over 30 min b.i.d.-q.i.d.  Monitor for superinfection.  For safety, keep out of reach of children.

22 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Case Study A client develops a staphylococcal infection and is prescribed a cephalosporin, cefepime (Maxipime). Critical Thinking 1. Which generation of cephalosporins is cefepime? Give an example drug from each of the other generations. 2. Differentiate the actions of the four generations of cephalosporins.

23 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Practice Question #1 Which nursing intervention is a higher priority for the client who is taking cefepime (Maxipime)? A. Wait until culture results are received before initiating antibiotic. B. Monitor the client for signs and symptoms of a superinfection. C. Administer IV cephalosporins over 2 hours to prevent phlebitis. D. Instruct the client to take the drug for 5 days only.

24 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Practice Question #1 (cont’d) Answer: B Rationale: Superinfection is a common adverse effect of antibiotics. The nurse should culture the infected area before initiating antibiotics and may begin drug therapy before culture results are received. IV cephalosporins should be administered over 30 to 45 minutes, not 2 hours. Cephalosporins are usually given 10 days for a full regimen.

25 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Practice Question #2 A client is taking piperacillin-tazobactam (Zosyn). Which nursing interventions are most appropriate for this drug? (Select all that apply.) A.Usually given with an aminoglycoside. B.Spend specimen to lab for C&S before antibiotic therapy is started. C.Instruct client to take entire prescribed drug. D.Instruct client to restrict fluid intake. E.Monitor for symptoms of superinfection including stomatitis and vaginitis.

26 Copyright © 2012, 2009, 2006, 2003 by Saunders, an imprint of Elsevier Inc. Practice Question #2 (cont’d) Answer: B, C, E Rationale: An extended-spectrum penicillin is not given with an aminoglycoside, as it may inactivate the aminoglycoside. Before any antibiotic, a C & S should be done. One should take the entire prescribed drug to avoid drug resistance. Clients should increase fluid intake, not restrict it. Symptoms of superinfection should always be monitored for all antibiotics.