chapter 39: antibiotics part 2

with quinolones, if the patient needs to take calcium or magnesium when should they take it?

1 hour before or after the quinolone

quinolones should be infused over what amount of time?

1 to 1.5 hours

not only do serum levels needed to be monitored to prevent toxicity, but it has been shown for aminglycosides to be effective, the serum level needs to be what?

8 times higher than the MIC

The nurse is planning care for a client prescribed once-daily IV gentamicin (Garamycin) therapy. When should the nurse schedule a trough drug level to be drawn? A. 12 hours after completing the antibiotic infusion B. 18 hours after completing the antibiotic infusion C. 30 minutes after beginning the antibiotic infusion D. 60 minutes after beginning the antibiotic infusion

A. 12 hours after completing the antibiotic infusion Trough serum drug levels should be drawn at least 8 to 12 hours after the medication is infused.

When providing instructions to clients on use of antibiotics, which instructions would the nurse include in the teaching? (Select all that apply.) A. Complete the entire course of therapy. B. Increase fluid intake up to 3000 mL/day. C. Wash your hands before and after preparing food. D. Notify the provider of any possible reactions that occur. E. Save unused medication in a cool dry place for later use.

A. Complete the entire course of therapy. B. Increase fluid intake up to 3000 mL/day. C. Wash your hands before and after preparing food. D. Notify the provider of any possible reactions that occur. There should not be any leftover medication, but if there is, it needs to be discarded in the appropriate method. The health care provider typically only writes a prescription for the exact amount of medication needed by the client.

The client's culture has grown gram-positive cocci, and the health care provider prescribes two different antibiotics, one of which is gentamicin (Garamycin). To treat this type of infection, which type of antibiotic is typically prescribed together with gentamicin (Garamycin)? A. Penicillin B. Cephalosporin C. Fluoroquinolone D. Aminoglycoside

A. Penicillin In gram-positive cocci, gentamicin is usually given in combination with a penicillin antibiotic. The other antibiotics are not typically prescribed with gentamicin for this culture result.

When performing discharge teaching for a client prescribed oral linezolid (Zyvox) to treat methicillin-resistant Staphylococcus aureus (MRSA), the nurse should emphasize which important information? A. Stop the drug as soon as you feel better. B. Avoid ingestion of foods containing tyramine. C. Report any occurrence of constipation or facial flushing. D. Take the drug with an antacid to avoid gastrointestinal (GI) upset.

B. Avoid ingestion of foods containing tyramine. Hypertension may occur in clients consuming tyramine-containing foods such as aged cheese or wine, soy sauce, smoked meats or fish, and sauerkraut while taking linezolid. Linezolid causes diarrhea, not constipation, and should be taken with food to decrease GI distress. An antacid would interfere with absorption.

For a client receiving an intravenous (IV) infusion of gentamicin (Garamycin), the nurse would monitor which laboratory values? A. Hematocrit and hemoglobin B. Blood urea nitrogen (BUN) and creatinine C. Prothrombin time and partial thromboplastin time D. Serum glutamic-oxaloacetic transaminase and alanine transaminase

B. Blood urea nitrogen (BUN) and creatinine Gentamicin has a high potential for nephrotoxicity. Nephrotoxicity typically occurs in 5% to 25% of clients. Thus, the client's renal function test results for BUN and creatinine must be monitored closely throughout therapy.

A client who is prescribed metronidazole (Flagyl) for a gynecologic infection provides the nurse with a list of medications that are routinely taken. Which medication would lead the nurse to question the prescription for Flagyl? A. Ibuprofen (Advil) B. Lithium (Eskalith) C. Levothyroxine (Synthroid) D. Multivitamin (Thera-Tabs)

B. Lithium (Eskalith) Concomitant use of lithium and metronidazole may result in lithium toxicity. Thus, a client who reports taking lithium should alert the nurse to notify the health care provider because of the potential significant interaction.

The nurse would teach a client prescribed metronidazole (Flagyl) to avoid ingestion of which drink? A. Milk B. Wine C. Coffee D. Orange juice

B. Wine A disulfiram-like (Antabuse) reaction may occur with concurrent ingestion of metronidazole and alcohol, leading to facial flushing, tachycardia, palpitations, nausea, and vomiting

During intravenous quinolone therapy in an 88-year-old patient, which potential problem is of most concern when assessing for adverse effects? A) Hepatotoxicity B) Rhabdomyolysis C) Tendon rupture D) Nephrotoxicity

C) Tendon rupture This effect is more common in elderly patients, patients with renal failure, and those receiving concurrent glucocorticoid therapy (e.g., prednisone).

A group of office workers is concerned because a package was opened that contained a white powder substance. There is a concern that the white powder is anthrax. Which drug does the nurse anticipate being prescribed for the office workers? A) daptomycin (Cubicin) B) colistimethate (Coly-Mycin) C) ciprofloxacin (Cipro) D) quinupristin/dalfopristin (Synercid)

C) ciprofloxacin (Cipro)

The nurse should assess a client for nephrotoxicity and ototoxicity when administering which antimicrobial? A. Cefazolin (Ancef) B. Clindamycin (Cleocin) C. Gentamicin (Garamycin) D. Erythromycin

C. Gentamicin (Garamycin) Aminoglycoside antibiotics, including gentamicin, have a high risk for nephrotoxicity and ototoxicity.

Quinolones are a class of antibiotics known for several significant complications. Which are possible adverse effects with these drugs? (Select all that apply.) A. Ototoxicity B. Nephrotoxicity C. Tendon rupture D. Prolongation of the QT interval E. Abnormal cartilage development in children

C. Tendon rupture D. Prolongation of the QT interval E. Abnormal cartilage development in children Quinolones are not used in prepubescent children because of the risk of cartilage development issues. Quinolones may also cause a cardiac effect that involves prolongation of the QT interval on the electrocardiogram. The use of these medications can result in tendonitis or ruptured tendons in adults. Nephrotoxicity and ototoxicity are not associated with quinolones.

A 58-year-old man is receiving vancomycin as part of the treatment for a severe bone infection. After the infusion, he begins to experience some itching and flushing of the neck, face, and upper body. He reports no chills or difficulty breathing. The nurse should suspect: A) an allergic reaction has occurred. B) an anaphylactic reaction is about to occur. C) the medication will not be effective for the bone infection. D) the IV dose may have infused too quickly

D) the IV dose may have infused too quickly These symptoms are know as red man syndrome and may occur during or after an infusion of vancomycin. This syndrome is characterized by flushing and/or itching of the head, face, neck, and upper trunk area. Symptoms can usually be alleviated by slowing the rate of infusion to at least 1 hour. Red man syndrome is bothersome but usually not harmful. Rapid infusions may also cause hypotension.

The nurse will question the use of a fluoroquinolone antibiotic in a client already prescribed which medication? A. Furosemide (Lasix) B. Omeprazole (Prilosec) C. Metoprolol (Lopressor) D. Amiodarone (Cordarone)

D. Amiodarone (Cordarone Dangerous cardiac dysrhythmias are more likely to occur when quinolones are taken by clients receiving class Ia and class III antidysrhythmic drugs such as disopyramide and amiodarone. For this reason, such drug combinations should be avoided.

Which is a complication of vancomycin IV infusions? A. Angioedema B. Neurotoxicity C. Cardiomyopathy D. Red man syndrome

D. Red man syndrome When infused too rapidly, clients receiving vancomycin may develop hypotension accompanied by flushing or itching of the head, face, neck, and upper trunk area. This phenomenon is called red man syndrome.

with quinolones, why would you need to assess baseline liver function studies?

Liver injury may occur with quinolones

quinolones are often combined with aminoglycosides to treat?

P. aeruginosa infections

do quinolones have good oral absorption?

YES, it is comparable to that of IV injection

When administering vancomycin, the nurse knows that which of these is most important to assess before giving the medication? a. Renal function b. WBC count c. Liver function d. Platelet count

a. Renal function

metronidazole interactions

acute alcohol intolerance when taken with alcoholic beverages due to the accumulation of acetaldehyde (alcohol metabolite)

For patients requiring a CT scan with contrast who are also on a nephrotoxic medication, what would you do?

alert the prescriber to the situation so that the dose may be adjusted and additional fluids and/or medications ordered

concurrent use of quinolones with which drugs causes a reduction in the oral absorption of the quinolone?

antacids, calcium, magnesium, iron, zinc preparations, or sucralfate, dairy products, enteral tube feedings

ciprofloxacin (Cipro) indications

anthrax; respiratory, skin, urinary tract, prostate, intraabdominal, GI, bone, and joint infections; typhoid fever; selected health care associated pneumonia, chlamydia, mycoplasma, mycobacteria

intravaginal doses of metronidazole are to be administered when?

at bedtime `

when should interacting drugs be taken with quinolones?

at least one hour before or after taking quinolones

the therapeutic goal for aminoglycoside trough concentration is?

at or below 1mcg/mL

8. A patient has been receiving therapy with the aminoglycoside tobramycin, and the nurse notes that the patient's latest trough drug level is 3 mcg/mL. This drug is given daily, and the next dose is to be administered now. Based on this trough drug level, what is the nurse's priority action? a. Administer the drug as ordered. b. Hold the drug, and notify the prescriber. c. Call the laboratory to have the test repeated and verified. d. Hold this dose, but administer the next dose as scheduled.

b. Hold the drug, and notify the prescriber.

are aminglycosides bactericidal or bacteriostatic?

bactericidal

are quinolones bactericidal or bacteriostatic?

bactericidal

why shouldn't patients chew extended release dosage forms?

because it can cause the drug to be absorbed more rapidly

why should oral anticoagulants be used with caution in patients taking quinolones?

because of the antibiotic-induced alteration of the intestinal flora, which affects vitamin K synthesis

with quinolones, why would you need to assess for existing neuropathies?

because the quinolones may precipitate peripheral neuropathy

when taking both beta-lactams and aminoglycosides, which one do you take first?

beta-lactam antibiotic because it breaks down the cell wall allowing for the aminoglycoside to access the ribosomes

aminoglycoside MOA

bind to 30S ribosome and prevent protein synthesis

6. The nurse is administering an intravenous aminoglycoside to a patient who has had gastrointestinal surgery. Which nursing measures are appropriate? (Select all that apply.) a. Report a trough drug level of 0.8 mcg/mL, and hold the drug. b. Enforce strict fluid restriction. c. Monitor serum creatinine levels. d. Instruct the patient to report dizziness or a feeling of fullness in the ears. e. Warn the patient that the urine may turn darker in color.

c. Monitor serum creatinine levels. d. Instruct the patient to report dizziness or a feeling of fullness in the ears.

When giving intravenous quinolones, the nurse needs to keep in mind that these drugs may have serious interactions with which drugs? a. Selective serotonin reuptake inhibitor antidepressants b. Nonsteroidal antiinflammatory drugs c. Oral anticoagulants d. Antihypertensives

c. Oral anticoagulants

A patient has been admitted for treatment of an infected leg ulcer and will be started on intravenous linezolid. The nurse is reviewing the list of the patient's current medications. Which type of medication, if listed, would be of most concern if taken with the linezolid? a. Beta blocker b. Oral anticoagulant c. Selective serotonin reuptake inhibitor antidepressant d. Thyroid replacement hormone

c. Selective serotonin reuptake inhibitor antidepressant

drug of choice for treatment of anthrax?

ciprofloxacin (Cipro)

a property of some antibiotics, especially aminoglycosides, whereby achieving high plasma drug concentrations, even if briefly, results in the most effective bacterial kill

concentration-dependent killing

with aminoglycosides, what increases the risk for ototoxicity?

concurrent use with loop diuretics

While assessing a woman who is receiving quinolone therapy for pneumonia, the nurse notices that the patient has a history of heart problems. The nurse will monitor for which potential cardiac effect of quinolone therapy? a. Bradycardia b. Dysrhythmias c. Tachycardia d. Prolonged QT interval

d. Prolonged QT interval

During therapy with an intravenous aminoglycoside, the patient calls the nurse and says, "I'm hearing some odd sounds, like ringing, in my ears." What is the nurse's priority action at this time? a. Reassure the patient that these are expected adverse effects. b. Reduce the rate of the intravenous infusion. c. Increase the rate of the intravenous infusion. d. Stop the infusion immediately.

d. Stop the infusion immediately.

when quinolones are taken with drugs such as amiodarone and disopyramide, what can happen?

dangerous cardiac dysrhythmias

quinolone MOA

destroy bacteria by altering their DNA and accomplish this by interfering with the bacterial enzymes DNA gyrase and topoisomerase

metronidazole adverse effects

dizziness, HA, GI discomfort, nasal congestion, reversible neutropenia and thrombocytopenia

what are the signs and symptoms of superinfection?

fever, perineal itching, cough, lethargy, or any unusual discharge

quinolones are also referred to as?

fluoroquinolones

Oral forms of metronidazole need to be given with?

food or meals to help decrease GI upset

quinolone indications

gram-negative bacteria such as pseudomonas, complicated UTI, respiratory, bone and joint, GI, skin, and STIs, anthrax, cystic fibrosis (kids)

aminoglycosides indications

gram-negative>>pseudomonas spp., E. coli, proteus spp., Klebsiella spp., Serratia spp., acinetobacter spp. gram-positive>> enterococcus spp., S. aureus, bacterial endocarditis prophylaxis in procedure involving GI or GU (enterococcal) surgical patients with a history of valvular heart disease (prone to enterococcal infection)

with aminoglycosides, what should you assess for?

hypersensitivity, and preexisting health conditions or altered neurologic and renal function

metronidazole MOA

interferes with microbial DNA synthesis, similar to quinolones

when taking quinolones, nitrofurantoin has what effect?

it can antagonize the antibacterial activity of the quinolones

when taking quinolones, what effect does probenecid have?

it can reduce the renal excretion of quinolones

quinolones contraindications

known drug allergy

metronidazole contraindications

known drug allergy, first trimester of pregnancy

aminoglycosides contraindications

known drug allergy, pregnancy (results in bilateral congenital deafness), lactating women

metronidazole may also increase the toxicity of which drugs?

lithium, benzodiazepines, cycloporine, calcium channel blockers, various antidepressants, and warfarin

adverse effects of quinolone therapy

long term>>bacterial overgrowth prolonged QT interval in ECG, tendinitis, tendon rupture (older people, renal failure, concurrent glucocorticoid therapy), CNS stimulation (seizures), peripheral neuropathy, liver injury (older adults), tinnitus, dysphagia, increased ALT and AST levels, flatulence, heartburn, N/V, HA, dizziness, insomnia, convulsions

what affect do phenytoin and phenobarbital have on metronidazole?

may reduce the effects of metronidazole due to CP450 liver enzymes that alter drug metabolism

a laboratory measure of the lowest concentration of a drug needed to kill a certain standardized amount of bacteria

minimum inhibitory concentration

MRSA, vancomycin-resistant enterococcus, extended-spectrum beta-lactamases, and carbapenem-resistant enterobacteriaceae are examples of what?

multi-drug resistant organisms

bacteria that are resistant to one or more classes of antimicrobial drugs

multi-drug resistant organisms

how long must patients avoid alcohol for when taking metronidazole?

must avoid alcohol for 24 hours before initiation of therapy and for at least 36 hours after the last dose of metronidazole

aminoglycosides adverse effects

nephrotoxicity, ototoxicity, HA, paresthesia, fever, superinfections, vertigo, skin rash, dizziness, tinnitus, neuromuscular paralysis

are aminoglycosides given orally?

no, because they have poor oral absorption

trough levels higher than 2 mcg/mL are associated with a greater risk for?

ototoxicity and nephrotoxicity

a period of continued bacterial suppression that occurs after brief exposure to certain antibiotic drug classes, especially aminoglycosides and carbapenems

postantibiotic effect

aminoglycosides have what effect on warfarin?

potentiate warfarin toxicity due (reduces the amount of vitamin K)

the risk for aminoglycoside toxicities is greater in patient with?

preexisting renal impairment, patients receiving renally toxic drugs, patients receiving high-dose or prolonged aminoglycoside therapy

metronidazole indications

primarily anaerobic (peptostreptococcus spp., eubacterium spp., bacteroides spp., and clostridium spp.) and gram-negative infections of abdominal cavity , skin, bone, and respiratory and GU tracts widely used to treat intraabdominal and gynecologic infections used for protozoal infections such as amebiasis and trichomoniasis antibiotic associated colitis

tobramycin is indicated for?

primarily gram-negative infections along with severe staph infections and is commonly used to treat recurrent pulmonary infections in patients with cystic fibrosis

concurrent use of aminglycosides and neuromuscular blocking drugs may do what?

prolong the duration of action of the neuromuscular blockafde

drug interaction in which the bacterial killing effect of two antibiotics given together is greater than the sum of the individual effects of the same drugs given alone

synergistic effect

ongoing monitoring of plasma drug concentrations and dosage adjustment based on these values as well as other laboratory indications such as kidney and liver function test results and is often carried out by a pharmacist in collaboration with medical, nursing, and laboratory staff

therapeutic drug monitoring

a property of most antibiotic classes whereby prolonged high plasma drug concentrations are required for effective bacterial kill

time-dependent killing

gentamycin is indicated for?

treatment of infection with several susceptible gram-positive and gram-negative bacteria, but is primarily gram-negative infections along with severe staph infections

with aminoglycosides, the risk for nephrotoxicity can be increased with concurrent use of other nephrotoxic drugs such as?

vancomycin, cyclosporine, and amphotericin B

when taking aminoglycosides, patients with myasthenia gravis or Parkinson's disease may experience?

worsening of muscle weakness because of the drug's neuromuscular blockade