chapter 40 fall 2012

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins

Chapter 40Antibiotics Affecting Protein

Synthesis

Chapter 40Antibiotics Affecting Protein

Synthesis


Aminoglycosides Aminoglycosides

• The aminoglycosides have been in use since 1944.

• Effective antibiotics for treating severe infections.

• General use is limited because of the potential for serious adverse effects which are :

Ototoxicity and nephrotoxicity

• Prototype drug: gentamicin.

• Usually given intravenously : onset rapid

duration 6- 8 hrs.


Gentamicin: Core Drug Knowledge Gentamicin: Core Drug Knowledge

• Pharmacotherapeutics

– Serious infections (such as urinary tract infections, peritonitis, endocarditis, sepsis, osteomyelitis)

– Effective against gram negative bacilli

• Pharmacokinetics

– Distribution: throughout the body (except CSF).

– Higher concentration in kidneys than serum.

• Pharmacodynamics

– Affects protein synthesis within the cell


Gentamicin: Core Drug Knowledge (cont.)Gentamicin: Core Drug Knowledge (cont.)

• Contraindications

– Pregnancy and lactation

Precautions – known allergy to any aminoglycoside

renal or hepatic disease, pre-existing hearing loss

• Adverse effects

– Neurotoxicity, nephrotoxicity, & ototoxicity

• Drug interactions

– Acyclovir, amphotericin B, cephalothin, cisplatin, cyclosporine, loop diuretics, and vancomycin


Gentamicin: Core Patient Variables Gentamicin: Core Patient Variables

• Health status

– Past medical and any kidney problems.

• Life span and gender

– Ototoxic to fetus, assess pregnancy status.

• Lifestyle, diet, and habits

– Assess the nutritional status of the patient. Dehydrated patients have an risk of nephrotoxicity

• Environment

– Assess environment where drug will be given.


Gentamicin: Nursing Diagnoses and Outcomes Gentamicin: Nursing Diagnoses and Outcomes

• Risk for Injury related to potential drug-related allergic reactions or suppression of bone marrow function

– Desired outcome: the patient will remain free of injury and will contact the prescriber if unusual adverse effects occur.

• Diarrhea related to drug effects

– Desired outcome: the patient will avoid dehydration, maintain fluid intake, and contact the prescriber if diarrhea persists.

• Excess Fluid Volume related to potential nephrotoxicity

– Desired outcome: the patient will report any weight gain exceeding 3 lb to the health care prescriber.


Gentamicin: Planning & InterventionsGentamicin: Planning & Interventions• Maximizing therapeutic effects

– Make sure that patients receive the full course as prescribed at around-the-clock intervals.

– Do not give at the same time as some forms of penicillin (space the drugs 2 hrs. apart )

• Minimizing adverse effects

– Maintain blood levels of gentamicin within a therapeutic margin that is very narrow.

– Monitor for signs of ototoxicity and nephrotoxicity.

– Monitor peak and trough blood levels


Peak and Trough LevelsPeak and Trough Levels

• Certain drugs require peak and trough levels

• These measure the amount of drug within the blood

• Peak levels are those that are the highest levels in the blood

• Peak levels are drawn 30 minutes after the completion of a 30 minute IV administration of Gentamycin

• Peak levels are drawn 30- 60 minutes after completion of IV administration of Vancomycin

• Trough Level is the lowest level of the drug in the blood

• Trough Levels are drawn just before the next dose of the drug is to be administered


Gentamicin: Teaching, Assessment & EvaluationsGentamicin: Teaching, Assessment & Evaluations• Patient and family education

– Patient should not take drug if pregnant or breastfeeding.

– Teach patients how to identify, report, and manage signs and symptoms of allergic reaction and adverse effects.

– If pt. has experienced an allergic reaction , they should not take any drug that has “micin” in it.

• Ongoing assessment and evaluation

– Discuss the addition of other potentially nephrotoxic or ototoxic drugs


QuestionQuestion

• Gentamicin is effective against what organism(s)?

– A. Pseudomonas aeruginosa

– B. Proteus mirabilis

– C. Klebsiella

– D. Enterobacter

– E. All of the above


RationaleRationale

• Gentamicin is effective against what organism (s)?

– E. All of the above

– Gentamicin is effective in managing infections caused by gram-negative bacilli.

• Susceptible organisms include Pseudomonas aeruginosa, Proteus mirabilis, Escherichia coli; Klebsiella, Enterobacter, Serratia, and Citrobacter species; and staphylococci.

• Gentamicin must be transported across the cell membrane in order to enter the cell and disrupt protein synthesis.

• This process requires oxygen; therefore, gentamicin and other aminoglycosides are ineffective against anaerobes.


Clindamycin: Core Drug Knowledge Clindamycin: Core Drug Knowledge


– Aerobic gram-positive cocci and several anaerobic gram-negative and gram-positive organisms.


– Varies with route of administration.

– Metabolized: liver. Excreted: bile and urine.


– Enters the bacterial cell and binds to bacterial ribosomes, suppressing protein synthesis.


Clindamycin: Core Drug Knowledge Clindamycin: Core Drug Knowledge

• Contraindications

pregnancy, and lactation

hypersensitivity

renal or hepatic dysfunction

• Adverse effects

– Pseudomembranous colitis{Black Box warning} maculopapular rash, erythema, and pruritus , nausea and vomiting

• Drug interactions are numerous

• Very toxic drug


Clindamycin: Core Patient Variables Clindamycin: Core Patient Variables

• Health status

– Assess for allergy to medication.


Used in pregnancy only if benefit outweighs the risk

– Assess the growth and developmental level of the child or infant ( use cautiously in infants and children)


– Assess lifestyle to ensure that drug will be given properly.

• Environment



Clindamycin: Nursing Diagnoses and Outcomes Clindamycin: Nursing Diagnoses and Outcomes

• Risk for Injury related to allergic reactions

– Desired outcome: the patient will stop drug therapy and immediately report symptoms of allergic reaction to the prescriber.

• Diarrhea related to drug effects

– Desired outcome: the patient will avoid dehydration and report persistent diarrhea to the provider.

• Risk for Injury related to possible blood dyscrasias

– Desired outcome: the patient will remain injury free throughout drug therapy.


Clindamycin: Planning & InterventionsClindamycin: Planning & Interventions

• Maximizing therapeutic effects

– Make sure that the patient receives the full course of clindamycin as prescribed.

– Coordinate the administration of drugs to decrease potential undesired interactions.


– Clindamycin should be administered on an empty stomach with a full glass of water.

– Report diarrhea to the provider immediately.

– Always check that C & S reports indicate sensitivity to Clindamycin


Clindamycin: Teaching, Assessment & EvaluationsClindamycin: Teaching, Assessment & Evaluations

• Patient and family education

– Advise patients to contact the prescriber immediately if they experience diarrhea.

– Teach patients to recognize and report symptoms of allergic reaction and superinfection.


– Monitor the patient for the onset of diarrhea.


QuestionQuestion

• What is the most serious adverse reaction of clindamycin administration?

– A. Respiratory arrest

– B. Pseudomembranous colitis

– C. Ventricular tachycardia

– D. Ototoxicity

Answer : B


Macrolide Antibiotics Macrolide Antibiotics

• The macrolide antibiotics have been in use since 1952.

• They are characterized by molecules made up of large-ring lactones.

• Macrolides are bacteriostatic or bactericidal in susceptible bacteria.

• Prototype drug:

erythromycin ( E-mycin, Erythrocin Stearate)


Erythromycin: Core Drug Knowledge Erythromycin: Core Drug Knowledge Pharmacotherapeutics

• More effective against gram positive organisms

• Used for patients that are allergic to penicillin

– Treating Legionnaire disease, Mycoplasma pneumoniae pneumonia, diphtheria,and chlamydial infections


– Drug is easily inactivated by gastric acid ( various formulations are available to prevent this)

– Peak 1–4 hours ( orally) : 1 hour ( intravenously)

– Metabolized: liver.

– Excreted: urine & bile.


Erythromycin: Core Drug Knowledge (cont.)Erythromycin: Core Drug Knowledge (cont.)


– Inhibiting protein synthesis

• Contraindications and precautions

– Allergy to medication

• Adverse effects

– GI symptoms, urticaria, maculopapular rash, erythema, and interstitial nephritis


Erythromycin: Core Patient Variables Erythromycin: Core Patient Variables

• Health status

– Assess medical history and allergies.


– Assess pregnancy and lactation status.

– ( excreted in breast milk at about 50% of maternal plasma concentrations which can cause diarrhea or superinfection in the infant)


– Avoid Grapefruit juice increases the serum concentration of erythromycin and may cause toxicity /side effects

– Take medication 1 hr. before or 2 hrs. after a meal


Erythromycin: Nursing Diagnoses and Outcomes Erythromycin: Nursing Diagnoses and Outcomes

• Risk for Injury related to possible allergic reactions

– Desired outcome: the patient will stop drug therapy and report any signs of allergic reaction immediately to the prescriber.

• Diarrhea related to drug-induced GI upset

– Desired outcome: the patient will avoid dehydration, maintain fluid intake, and contact the prescriber if diarrhea persists.

• Risk for Infection related to potential for superinfection following drug therapy

– Desired outcome: the patient will contact the provider if any signs of superinfection occur, for example, sore throat or fever.


Erythromycin: Planning & InterventionsErythromycin: Planning & Interventions


– Reconstitute IV Erythromycin with sterile water only.

– Prepared infusion solutions that are stored at room temperature must be used within 8 hours.


– Because erythromycin can be very irritating to veins, it is important to administer IV infusions over 30 to 60 minutes.


Erythromycin: Teaching, Assessment & EvaluationsErythromycin: Teaching, Assessment & Evaluations


– Encourage patients to take the complete course of antibiotics.

– Advise patients to take erythromycin on an empty stomach (unless GI distress is unbearable)


– Monitor for signs of allergic reactions, resolution of presenting signs and symptoms of infection, and signs of superinfection.


RationaleRationale

• Grapefruit juice will decrease the serum concentration of erythromycin.

- A. True

– B. False

Answer : B

– Instruct the patient to avoid grapefruit or grapefruit juice because it increases the serum concentration of erythromycin and may cause adverse effects or toxicity.


Chloramphenicol: Core Drug Knowledge Chloramphenicol: Core Drug Knowledge

• Antibiotic that also affects protein synthesis


– True broad-spectrum antibiotic (effective against gram negative and gram positive organisms; not fungi)


– Administered: oral and IV. Peak 1–3 hours.

– Passes through the blood brain barrier


– Inhibiting the protein synthesis of bacterial cells.


Chloramphenicol: Core Drug Knowledge Chloramphenicol: Core Drug Knowledge • Precautions

This drug is relatively toxic and has a Black Box Warning

To be used only in serious infections in which no other drug is effective or in patients with resistance or allergies

• Adverse effects

– Aplastic anemia, thrombocytopenia, and granulocytopenia ( depressed bone marrow function)

• Drug interactions

– Many different types of drugs


Chloramphenicol: Core Patient Variables Chloramphenicol: Core Patient Variables

• Health status

– Assess medical history. Establish baseline labs, CBC , hepatic and renal function


– Contraindicated in pregnancy since it can cause bone marrow depression or gray baby syndrome in the neonate.

• Environment



Chloramphenicol: Nursing Diagnoses and Outcomes Chloramphenicol: Nursing Diagnoses and Outcomes

• Risk for Injury related to drug-induced adverse effects, such as blood dyscrasias, gray baby syndrome, and CNS effects, including optic or peripheral neuritis, headache, depression, confusion, or delirium

– Desired outcome: regular and careful monitoring will protect the patient from permanent drug-related adverse effects.

• Risk for Impaired Skin Integrity, rash and pruritus, related to topical drug use

– Desired outcome: the nurse and patient will observe for and report signs of unusual skin reaction and contact the prescriber.


Chloramphenicol: Planning & InterventionsChloramphenicol: Planning & Interventions


– Oral chloramphenicol should be administered on an empty stomach 1 hour before or 2 hours after meals.


– Monitor plasma concentrations at least weekly or more often in patients with hepatic or renal impairment.


Chloramphenicol: Teaching, Assessment & EvaluationsChloramphenicol: Teaching, Assessment & Evaluations


– Explain the importance of completing therapy.

– Teach patients the importance of measuring fluid intake and output accurately.


– For patients receiving systemic therapy, coordinate serial monitoring of chloramphenicol plasma concentrations. ( peak and trough levels can be done)

chapter 40 fall 2012

Documents