Pharmacology Review Chapter 45

While talking with a patient, the nurse noticed that the patient frequently asked the nurse to repeat what was said. After reviewing the chart, the nurse found there was no prior mention of hearing loss. The nurse became concerned about possible ototoxicity when the patient was also receiving this drug: 1. levofloxacin (Levaquin). 2. linezolid (Zyvox). 3. azithromycin (Zithromax). 4. neomycin (Neo-Fradin).

ANS: 4 Neomycin (Neo-Fradin) is an aminoglycoside used primarily against gram-negative microorganisms that cause urinary tract infections (UTI)s, meningitis, wound infections, and life-threatening septicemias. It is one of the mainstays in the treatment of healthcare-associated gram-negative infections (e.g., Acinetobacter spp., Citrobacter spp., Enterobacter spp., E. coli, Klebsiella spp., Providencia spp., Pseudomonas spp., Salmonella spp., and Shigella spp.). Ototoxicity is damage to the eighth cranial nerve and can occur as a result of aminoglycoside therapy. Patients must also be observed for ototoxicity after therapy has been discontinued. These adverse effects may appear several days later and are manifested by dizziness, tinnitus, and progressive hearing loss. Patients must be assessed for difficulty in walking unaided, and the level of hearing daily. The nurse must speak intentionally softly to patients and note if they are aware that anything was said. Focus on the patient who repeatedly asks, "What did you say?" or who starts talking more loudly or progressively increases the volume on the television or radio. Levofloxacin (Levaquin) is a member of the quinolone class of drugs. Fluoroquinolones, which is a subgroup of quinolones, are effective against a wide range of gram-positive and gram-negative bacteria, including some anaerobes. Phototoxic but not ototoxic reactions have been reported in patients treated with fluoroquinolones. Linezolid (Zyvox) is the first of a new class of antimicrobial agents known as the oxazolidinones. It acts by inhibiting protein synthesis in bacterial cells and is used as a bactericidal in certain strains of bacteria and bacteriostatic in others. The most common adverse effects of linezolid therapy are nausea and vomiting and these adverse effects are usually mild and moderate in the first few days of therapy, but tend to resolve with continued therapy. It has not ototoxic effects on patients. Linezolid is used in the treatment of serious or life-threatening infections caused by gram-positive microorganisms, and approved for use with VRE bacteria and uncomplicated and cSSSIs caused by methicillin-susceptible and methicillin-resistant S. aureus, S. pyogenes, or S. agalactiae. It may also be used to treat community-acquired pneumonia caused by penicillin-susceptible S. pneumoniae. Azithromycin (Zithromax) is a macrolide and is used to treat bacterial infections such as respiratory, gastrointestinal (GI) tract, skin, and soft tissue infections and for sexually transmitted infections (STI)s, especially when penicillins, cephalosporins, and tetracyclines cannot be used. The most common adverse effects of oral macrolide therapy are diarrhea, nausea and vomiting, and abnormal taste. These are usually mild and tend to resolve with continued therapy. Macrolides do not have any ototoxic adverse effects. Patients need to be encouraged not to discontinue therapy without first consulting their healthcare provider.

Ertapenem (Invanz) was prescribed for a patient who came in to the hospital with cellulitis. The nurse performs the following assessments before administration. (Select all that apply.) 1. Assess for any allergies 2. Record the patient's temperature, pulse, respirations, and blood pressure 3. Obtain baseline assessments of presenting symptoms 4. Assess for any respiratory symptoms before initiating therapy 5. Implement seizure precautions

ANS: 1, 2, 3 Assessments the nurse needs to perform before medicating a patient with ertapenem (a carbapenem antibiotic) include: assess for any allergies including specifically asking about penicillin and cephalosporin allergies; record temperature, pulse, respirations, blood pressure, and hydration status; and obtain baseline assessments of presenting symptoms. Other assessments the nurse needs to perform include: assessing for and recording any gastric symptoms; obtaining baseline laboratory studies ordered and results reviewed; performing a baseline assessment of the patient's degree of alertness and orientation to name, place, and time; and asking whether there is a history of seizure activity. Assessing for any respiratory symptoms is not an assessment that needs to be performed before initiation of this drug. Implementation of seizure precautions is an intervention and not an assessment. Ertapenem is a broad spectrum drug approved to treat infections caused by aerobic and anaerobic gram-positive and gram-negative bacteria causing complicated intraabdominal infections, skin and skin structure infections, community-acquired pneumonia, urinary tract infections (UTI)s (including pyelonephritis), and acute pelvic infections.

The nurse is administering tobramycin, an aminoglycoside, to a patient with a wound infected with Klebsiella and is alert for these adverse effects. (Select all that apply.) 1. Ototoxicity 2. Nystagmus 3. Nephrotoxicity 4. Photosensitivity 5. Dizziness

ANS: 1, 3, 5 Damage to the eighth cranial nerve or ototoxicity, nephrotoxicity, and dizziness can occur from aminoglycoside drug therapy. Ototoxicity can be manifested by dizziness, tinnitus, and progressive hearing loss. The aminoglycosides are used primarily against gram-negative microorganisms that cause UTIs, meningitis, wound infections, and life-threatening septicemias and are the mainstays in the treatment of healthcare-associated gram-negative infections (e.g., Acinetobacter spp., Citrobacter spp., Enterobacter spp., E. coli, Klebsiella spp., Providencia spp., Pseudomonas spp., Salmonella spp., and Shigella spp.). The nurse needs to monitor urinalysis and kidney function tests for abnormal results and report increasing BUN and creatinine levels, decreasing urine output or decreasing specific gravity (despite amount of fluid intake), casts or protein in the urine, frank blood or smoky-colored urine, or RBCs in excess of 0-3 RBCs/HPF (see Table 41-1) on the urinalysis report. Nystagmus is related to phenytoin toxicity and not amminoglycoside toxicity. Photosensitivity is also not related to aminoglycoside toxicity.

Which of the following antibiotics may be prescribed for a patient with a working diagnosis of septicemia as a preliminary antibiotic for use before culture and sensitivity results are available? 1. Tinidazole (Tindamax) 2. Daptomycin (Cubicin) 3. Fluconazole (Diflucan) 4. Diphenhydramine (Benadryl)

ANS: 2 Daptomycin (Cubicin) may be prescribed for a patient with a working diagnosis of septicemia as a preliminary antibiotic before culture and sensitivity results are available. Daptomycin is in the class of antibiotics known as cyclic lipopeptide antibiotics and is effective against microorganisms that have developed resistance to other commonly used antibiotics. Its unique mechanism of action is binding to bacterial membranes and causing a rapid depolarization of membrane potential leading to inhibition of protein, RNA, and DNA synthesis, leading to cell death. It is particularly valuable in cases of gram-positive organisms becoming resistant to the beta-lactam (penicillins and cephalosporins) antibiotics and vancomycin. It should be used only when the pathogen is resistant to other available antibiotics.

A patient was complaining of nausea and vomiting after taking ampicillin. After reassuring the patient, the nurse responded with the following statement: 1. "I would not worry about feeling this way; these symptoms will go away in a couple of hours." 2. "Since the symptoms of nausea and vomiting are common responses to antibiotics, it may be helpful to take ampicillin with food." 3. "This is a sign that you are allergic to the drug. I will notify your physician." 4. "The drug needs to be discontinued, and you will need to be started on another drug."

ANS: 2 What a patient complains about nausea and vomiting after taking ampicillin, the nurse should reassure the patient by saying that, "Since the symptoms of nausea and vomiting are common responses to antibiotics, it may be helpful to take ampicillin with food." When drug therapy causes nausea and vomiting, the healthcare provider may elect to give the antibiotic with food to decrease irritation, even though absorption may be slightly decreased, or may choose to switch to a parenteral dosage form. When reporting any incidence of nausea and vomiting, all significant data should be collected and reported, along with the administration of any prescribed antiemetics or antidiarrheal agents (see also Chapters 33 and 34). Telling the patient not to worry about feeling this way and that these symptoms will go away in a couple of hours is incorrect. First, telling the patient not to worry is condescending and second, the symptoms will probably remain during the course of antibiotic treatment. Nausea and vomiting is a common response to taking antibiotics and does not indicate an allergy to the drug and does not require that the drug should be discontinued and another drug given. The nurse, however, should continue to assess the patient for any other adverse effects to the drug.

Prophylactic antibiotics are prescribed prior to dental procedures for patients at risk for developing infective endocarditis with the following medical conditions. (Select all that apply.) 1. Hypertension 2. Previous heart transplantation 3. History of infective endocarditis 4. Congestive heart failure 5. Congenital heart defects

ANS: 2, 3, 5 The use of prophylactic antibiotics before dental procedures to prevent infective endocarditis is recommended for patients with a history of heart transplantation, infective endocarditis, and congenital heart defects. This prophylactic treatment should also be used before gastric and genitourinary surgery and other invasive procedures. The American Heart Association (Wilson et al, 2007) guidelines recommend prophylactic antibiotic treatment for patients with cardiac conditions that put them at highest risk for infection, such as prosthetic cardiac valve; previous infective endocarditis; congenital heart disease (CHD); unrepaired, cyanotic CHD, including palliative shunts and conduits; congenital heart defects completely repaired with prosthetic material or device—whether placed by surgery or by catheter intervention—during the first 6 months after the procedure; repaired congenital heart defects with residual defects at the site or adjacent to the site of prosthetic patch or prosthetic device; and cardiac transplantation. A history of hypertension and congestive heart failure does not increase a patient risk for developing infective endocarditis with dental procedures.

A nurse knows that patients receiving amphotericin B may develop nephrotoxicity. The nurse knows that the following laboratory values need to be monitored for this adverse effect. (Select all that apply.) 1. Elevated AST levels 2. Increased BUN levels 3. Decreased serum creatinine levels 4. Elevated serum creatinine levels 5. Decreased BUN levels

ANS: 2, 4 Lab values that need to be monitored for nephrotoxicity in a patient taking amphotericin B include; increased and not decreased BUN levels and elevated and not decreased serum creatinine levels. Amphotericin B is used primarily in treating systemic life-threatening fungal infections, and should not be used to treat noninvasive fungal infections such as oral thrush, vaginal candidiasis, and esophageal candidiasis in immunocompetent patients with normal neutrophil counts. It is important to ensure that the correct dosage form is being reconstituted and diluted properly, and that proper administration technique, including the use of appropriate inline filters and rate of infusion, is being used. Combining amphotericin B with other nephrotoxic agents such as aminoglycosides, diuretics, or cisplatin should be monitored and done with extreme caution. Because amphotericin B may induce hypokalemia leading to digoxin toxicity, it should be used with caution in patients receiving digoxin. These patients should also be monitored for dysrhythmias, nausea, and bradycardia. Elevated AST levels are a sign of abnormal liver function along with elevated bilirubin, AST, ALT, GGT, alkaline phosphatase levels, and increased PT level.

A patient presented with the symptoms of white patches over the tongue while taking ceftriaxone (Rocephin) for pneumonia. The nurse recognized this as 1. ototoxicity. 2. an allergic reaction. 3. a secondary infection. 4. photosensitivity.

ANS: 3 A secondary infection is the tem used for the symptoms of white patches over the tongue a patient develops while taking ceftriaxone (Rocephin) for pneumonia. Oral thrush, genital and anal pruritus, vaginitis, and vaginal discharge may occur with cephalosporin therapy. These secondary infections must be reported promptly because they are resistant to the original antibiotic used. The patient must be taught the importance of meticulous oral and perineal personal hygiene. Ototoxicity from drug therapy is damage to the eighth cranial nerve, ototoxicity, can occur, particularly from aminoglycosides. This may initially be manifested by dizziness, tinnitus, and progressive hearing loss. Also, assess the patient for difficulty in walking unaided, and assess the level of hearing daily. The severity of allergic reactions range from a mild rash to fatal anaphylaxis. They can develop within 30 minutes of administration (e.g., anaphylaxis, laryngeal edema, shock, dyspnea, skin reactions) or occur several days after discontinuing therapy (e.g., skin rashes, fever). All patients must be questioned for previous allergic reactions, and allergy-prone patients must be observed closely. It is important that a patient not be labeled "allergic" to a particular medication without adequate documentation. For instance, patients who report gastrointestinal (GI) symptoms of nausea, vomiting, and/or diarrhea with no other symptoms (e.g., skin rash, facial edema, dyspnea, and hypotension) should not be labeled allergic to the medicine. The medication to which a patient claims an allergy may be a lifesaving drug for that patient in the future, Photosensitivity is the development of dermatologic symptoms such as exaggerated sunburn, itching, rash, urticaria, pruritus, and scaling, particularly after exposure to sunlight, and is seldom evident during hospitalization. It is more commonly seen in ambulatory practice. With some drugs, patients should be cautioned to avoid exposure to sunlight and ultraviolet light and encouraged to wear long-sleeved clothing, a hat, and sunglasses when outdoors. The use of tanning lamps should be discouraged. If photosensitivity does occur, the healthcare provider should be consulted about the advisability of discontinuing therapy.

The nurse was instructing a patient who was diagnosed with tuberculosis on the medications that were used to treat the disease. After the patient made the following statement, the nurse knew that further education was needed: 1. "The drugs that I need to take for TB are the isoniazid (INH) and the rifampin (Ridadin)." 2. "One of the common effects that I should be aware of is the potential for nausea and vomiting." 3. "My urine and tears may turn bright yellow with these drugs." 4. "I understand I need to take these drugs consistently or the organism develops a resistance to the drugs."

ANS: 3 The comment by a patient about tuberculosis drugs turning urine and tears bright yellow shows that the patient needs more education about tuberculosis medications. The other comments are correct. Rifampin is used in combination with other agents for the treatment of tuberculosis. Urine, feces, saliva, sputum, sweat, and tears may be tinged reddish orange. The effect is harmless and will disappear after discontinuing therapy, but it may permanently discolor soft contact lenses. Nausea and vomiting are relatively common adverse effects of isoniazid and are dose related. Patients should be warned that omission or interrupted intake of rifampin may result in drug resistance, reversal of clinical improvement, and increased susceptibility of family members to tuberculosis.

The antiviral agent ribavirin (Virazole) is used for treatment of which of the following infections? (Select all that apply.) 1. HIV-1 2. Herpes zoster (shingles) 3. Influenza 4. Chronic hepatitis 5. RSV

ANS: 3, 4, 5 The RNA viruses for which ribavirin exert inhibitory activity are the influenza and parainfluenza viruses and respiratory syncytial virus (RSV). The primary therapeutic outcome expected from ribavirin therapy is elimination of viral infection—RSV in infants and children and chronic hepatitis C in adults. Ribavirin is not used to treat HIV. It may antagonize the in vitro antiviral activity of stavudine and zidovudine against HIV. Combination therapy with zidovudine, ribavirin, and peginterferon alfa-2a can result in severe neutropenia and severe anemia. Virazole is not used to treat shingles. Valacyclovir is used orally to treat acute herpes zoster (shingles) in immunocompetent patients.