Exam 1 - Nursing Pharmacology

Nursing Process

-assessment -nursing diagnosis -planning -implementation (intervention) -evaluation

Passage of Drugs Across Membranes

-channels and pores -transport systems (P-glycoprotein) -direct penetration of the membrane

Selection of Antibiotics

-identify organsims -drug sensitivity of organism -host factors -drug may be ruled out owing to; + allergy + inability to penetrate site of infection + patient variables

Grapefruit juice vs. drugs

-inhibits the metabolism of certain drugs -raises the drug's blood levels -The effect is sometimes quite remarkable. In one study, the coadministration of grapefruit juice produced a 406% increase in blood levels of felodipine [Plendil], a calcium channel blocker used for hypertension. In addition to felodipine and other calcium channel blockers, -grapefruit juice can increase blood levels of lovastatin [Mevacor], cyclosporine [Sandimmune], midazolam [Versed], and many other drugs. This effect is not seen with other citrus juices -Grapefruit juice raises drug levels mainly by inhibiting metabolism.

A patient is taking two prescription medications that both cause bradycardia. The nurse should monitor the patient for which type of effect? a. An increased therapeutic effect b. An increased adverse effect c. A reduced therapeutic effect d. A reduced adverse effect

Answer: B Rationale: Both of the drugs have an adverse effect of bradycardia.

Which patient should receive prophylactic antibiotic therapy? A. A patient who is to have his teeth cleaned B. A patient who is scheduled for a hysterectomy C. A patient with a white blood cell count of 8000 cells/mm3 D. A patient with a high fever without an identifiable cause

Answer: B Rationale: Patients who undergo a hysterectomy (and other specific surgeries) may have a decreased incidence of infection if antibiotics are administered before or during surgery. Use of prophylactic antibiotics are not indicated for the other conditions.

Which individual is at the highest risk for a drug-drug interaction? a. A toddler who is prescribed two antibiotics for a serious infection b. An adolescent who takes over-the-counter medications for menstrual cramping c. An adult who takes eight prescription medications for a chronic condition d. An older adult who takes two prescription medications and a dietary supplement for anxiety

Answer: C Rationale: *The risk of a serious drug interaction is proportional to the number of drugs that a patient is taking*. In other words, the more drugs that the patient receives, the greater the risk for a detrimental interaction.

The nurse identifies which patient as being at highest risk for slow drug metabolism? a. A 2-year-old boy who is prescribed an oral antibiotic b. A 14-year-old girl who takes four prescription drugs c. A 56-year-old man who has chronic hepatic disease d. A 76-year-old woman who has an elevated temperature

Answer: C Rationale: Drug metabolism, which is also known as biotransformation, is the enzymatic alteration of drug structure. Most drug metabolism takes place in the liver.

Which of the following medications would *not* be administered through a nasogastric tube? (select all that apply) a. Liquids b.enteric coated tablets c. sustained released tablets d. finely crushed tablets e. IV medication

B,C,E

OTC drugs

OTC drugs account for 60% of all medications administered.

pharmacotherapeutics (therapeutics)

the use of drugs to diagnose, prevent, or treat disease -or used to prevent pregnancy

P-Glycoprotein

transmembrane protein that transports a wide variety of drugs out of cells

Hepatotoxic Drugs

*Leading cause of liver failure in the US - As some drugs undergo metabolism, they are converted to toxic products that can injure liver cells

Basic Mechanisms of Drug-Drug Interactions

- direct chemical or physical interactions -pharmacokinetic interaction -pharmacodynamic interaction -combined toxicity

Microbial Mechanisms of Drug Resistance - Four basic actions

-Decrease the concentration of a drug at its site of action -Inactivate a drug -Alter the structure of drug target molecules -Produce a drug antagonist

Three Properties of an "Ideal Drug"

-Effectiveness: Most important property a drug can have -Safety: Drug cannot produce harmful effects -Selectivity: Drug elicits only the response for which it is given -Reversible action (birth control-dont want it to last forever) -Predictability -Ease of administration -Freedom from drug interactions -Low cost -Chemical stability (shelf life) -Simple generic name

Key Points in Identifying high-risk patients

-Liver and kidney impairment -Genetic factors -Drug allergies -Pregnancy -Older adult or pediatric age group -Tools: Patient history, physical examination, and laboratory results

Rights of Drug Administration

-Right client -right drug -right dose -right route -right time -right documentation -right assessment -right evaluation -right of patient education -right of patient to refuse care

Minimizing Adverse Interactions

-Take a thorough drug history -Advise the patient to avoid over-the-counter drugs that can interact with the prescribed medication -Monitor for adverse interactions that are known to occur -Be alert for as-yet-unknown interactions

Paradoxical Effect

-The opposite of the intended drug response -For example, when using benzodiazepines for sedation to treat insomnia, excitement may occur instead (especially in children and older adults)

Four major pharmacokinetic processes

-drug absorption -drug distribution -drug metabolism -drug excretion

Public Health Action Plan to Combat Antimicrobial Resistance (four focus areas)

1- Survellieance 2- Prevention and Control 3- Research 4- Product Development

anaphylactic reactions and Penicillin

Anaphylactic reactions occur more frequently with penicillins than with any other drug. Allergy to penicillin can decrease over time. Epinephrine is the drug of choice for anaphylaxis. Vancomycin, erythromycin, and clindamycin are effective and safe alternatives for patients with penicillin allergy.

A nurse is administering a drug that is categorized as Schedule IV. The nurse understands that this means the drug: a. Has acceptable medical applications with low potential for abuse. b. Is a controlled substance with no accepted medical use. c. Is dangerous to administer to pregnant or breast-feeding patients. d. Has the potential for serious and life-threatening adverse effects.

Answer: A Rationale: Categories from Schedules I to V are used for drugs that are considered to have the potential for abuse. The drugs with the highest potential for abuse are Schedule I drugs, and those with the lowest potential for abuse are Schedule V drugs.

A nurse is caring for a patient who has an infection. The healthcare provider has ordered an antimicrobial drug for the patient. The nurse understands that which of the following is the most important characteristic of this drug? a. That the drug will kill the microorganism b. That the drug will be administered orally c. That the drug does not have any harmful effects d. That the drug does not interact with other drugs

Answer: A Rationale: The three most important characteristics that any drug can have are effectiveness, safety, and selectivity. Effectiveness is the most important property that a drug can have.

A patient is prescribed a medication to be taken on an empty stomach. Which statement should the nurse include when providing patient teaching? a."Take the medication 1 hour before eating." b."Take the medication with a small glass of water." c."Take the medication before going to bed at night." d."Take the medication 1 hour after a meal."

Answer: A Rationale: To administer a drug on an empty stomach means to administer it at least 1 hour before or 2 hours after a meal.

The nurse reviews a patient's admission orders written by the healthcare provider. Which medication order should the nurse question? a. Cyanocobalamin 100 mcg intramuscularly every month b. MSO4 2.0 mg IV every 2 to 4 hours as needed for pain c. Levothyroxine 75 mcg orally every morning d. Enoxaparin 40 mg subQ every day for 7 days

Answer: B Rationale: Miscommunication is a common cause of medication errors. To help reduce errors, a list of abbreviations, symbols, and dose designations that should not be used is available. "MSO4" should be written as "morphine sulfate," and a trailing zero should not be used after a final decimal point. The medication order should be written as "Morphine sulfate 2 mg IV every 2 to 4 hours as needed for pain."

A patient is prescribed a medication that is potentially hepatotoxic. Before administering the medication, it is most important for the nurse to assess what? a. Blood urea nitrogen and serum creatinine b. Aspartate aminotransferase and alanine aminotransferase c. Prolonged QT interval on the electrocardiogram d. Serum potassium, serum sodium, and serum magnesium

Answer: B Rationale: The nurse should assess the liver function tests of patients who are taking hepatotoxic drugs. When liver cells are injured, two liver enzymes (aspartate aminotransferase [AST] and alanine aminotransferase [ALT]) will be elevated.

A patient who was prescribed an oral medication to be taken four times per day returns to the clinic for a follow-up visit. The patient tells the nurse that he forgets to take two or three doses of the medication each day. What is the most appropriate action that the nurse can take? a. Arranging for the patient to have a home healthcare nurse b. Re-educating the patient about the medication and how it should be taken c. Determining whether the patient is experiencing any adverse effects d. Telling the patient to set an alarm as a reminder to take the drug

Answer: B Rationale: To help minimize errors caused by poor adherence, patients should receive thorough instruction regarding their medications and how to take them.

The nurse is reviewing laboratory values from a patient who has been prescribed gentamicin. To prevent ototoxicity, it is most important for the nurse to monitor which value(s)? A. Serum creatinine and blood urea nitrogen levels B. Trough drug levels of gentamicin C. Peak drugs levels of gentamicin D. Serum alanine aminotransferase and aspartate aminotransferase levels

Answer: B Rationale: To minimize ototoxicity, trough levels must be sufficiently low to reduce exposure of sensitive sensory hearing cells. The risk of ototoxicity is related primarily to persistently elevated trough drug levels rather than to excessive peak levels.

Which statement about superinfections does the nurse identify as true? A. Superinfections are more common in patients treated with narrow-spectrum drugs. B. Superinfection is defined as a new infection that appears. during the course of treatment for a primary infection. C. Superinfections are caused by viruses. D. Superinfections are easy to treat.

Answer: B Rationale: Because broad-spectrum antibiotics kill off more normal flora than do narrow-spectrum drugs, superinfections are more likely in patients receiving broad-spectrum agents. Suprainfections are caused by drug-resistant microbes; these infections are often difficult to treat.

Which patient does the nurse identify as being at highest risk for the development of an adverse drug reaction? A 1-month-old patient whose mother has allergies to penicillin, aspirin, and codeine A 16-year-old patient with multiple traumatic injuries who is taking morphine and an antibiotic A 54-year-old patient with multiple sclerosis who has been enrolled in a clinical trial of a new drug An 84-year-old patient with diabetes, heart failure, and hypertension who takes seven prescription medications each day

Answer: D Rationale: Adverse events are more common in older adults and the very young, in patients with severe illness, and in those who are taking multiple drugs.

Which tetracycline may be administered with meals? A. Tetracycline B. Demeclocycline C. Doxycycline D. Minocycline

Answer: D Rationale: Tetracycline, demeclocycline, and doxycycline should be administered on an empty stomach. Minocycline can be administered with meals.

Digoxin has a half-life of 36 to 48 hours. Because of the length of the half-life, the nurse expects dosing to occur how often? a. 4 times per day b. 3 times per day c. 2 times per day d. Once a day

Answer: D Rationale: The concept of the half-life tells us that, no matter what the amount of drug in the body may be, half (50%) will leave during a specified period of time (i.e., the half-life). The actual amount of drug that is lost during one half-life depends on just how much drug is present: The more drug that is in the body, the larger the amount lost during one half-life. If a long dosing interval were used, drug levels would fall below the minimum effective concentration between doses, and therapeutic effects would be lost. Conversely, if a drug has a long half-life, a long time can separate doses without a loss of benefits.

A patient is prescribed vancomycin orally for antibiotic-associated pseudomembranous colitis. The nurse will monitor the patient for what? A. Leukopenia B. "Red man" syndrome C. Liver impairment D. Ototoxicity

Answer: D Rationale: The most serious adverse effect of vancomycin is ototoxicity. "Red man" syndrome occurs only with rapid intravenous administration. Thrombocytopenia is an adverse effect of vancomycin

The healthcare provider writes a medication order that the nurse cannot read. What should the nurse do? a. Consult with the charge nurse to verify the order. b. Discuss the order with the pharmacist. c. Check with the patient to determine the correct medication. d. Contact the prescriber to clarify the order.

Answer: D Rationale: The nurse should contact the prescriber to clarify the order.

A prescriber states that a patient will need to receive penicillin intravenously. The nurse anticipates administering which drug? A. Penicillin V B. Procaine penicillin G C. Benzathine penicillin G D. Potassium penicillin G

Answer: D Rationale: When high blood levels are needed rapidly, penicillin can be administered IV. However, only the potassium salt should be administered by this route. Owing to poor water solubility, *procaine and benzathine salts must never be administered IV*. Penicillin V is administered orally.

Grapefruit juice inhibits P450 CYP3A4 drug metabolizing enzyme and inhibits p-glycoprotein in the intestines for days after ingestion. This especially affects calcium channel blockers, benzodiazepines, cyclosporine and "statin" drugs. The nurse should teach a patient who is prescribed any of these drugs that *drinking grapefruit can cause what problem*? a. Excessive first-pass effect b. Excessive levels of drug in the blood c. Lack of therapeutic effect d. Rapid excretion

B- excessive levels of drug in the blood

drug- drug interactions

When two drugs interact, there are three possible outcomes: (1) one drug may intensify the effects of the other, (2) one drug may reduce the effects of the other, or (3) the combination may produce a new response not seen with either drug alone.

When to measure peak levels

When using divided daily doses, draw blood samples for measuring peak levels *1 hour after IM injection and 30 minutes after completing an IV infusion*. When a single daily dose is used, measuring peak levels is unnecessary. Draw samples for trough levels just before the next dose (when using divided daily doses) or 1 hour before the next dose (when using a single daily dose).

iatrogenic

a disease produced by drugs aka a drug induced disease -ex: drugs for antipsychotic disorders can cause Parkinson's-like symptoms

tachyphylaxis

a reduction in drug responsiveness brought on by repeated dosing over a short time.

empiric therapy

antibiotic therapy for patients before causative organism is positively identified

antimicrobials

any agent that can kill or suppress microorganisms -used to treat infectious diseases- including drugs to treat bacteria, fungi, protozoa, viruses

classification of antimicrobial drugs (2)

classification by susceptibility classification by mechanism of action

pharmacodynamics

impact of drugs on the body - ex: placebo effect

altered metabolism

is one of the most important—and most complex—mechanisms by which drugs interact. Some drugs increase the metabolism of other drugs, and some drugs decrease the metabolism of other drugs. Drugs that increase the metabolism of other drugs do so by inducing synthesis of hepatic drug-metabolizing enzymes. Drugs that decrease the metabolism of other drugs do so by inhibiting those enzymes.

Antibiotics that affect bacterial cell wall

penicillins, cephalosporins, carbapenems

antagonist

prevents receptor activation

kidneys

pumps drugs into the urine for excretion

antibiotics

specific to only bacteria

Antibiotics that inhibit protein synthesis

tetracycline, aminoglycoside, macroglides

pharmacokinetics

the study of drug movement throughout the body

pharmacology

the study of drugs and their interactions with living systems

Liver

transports drugs into the bile for elimination

steps to new drug development

trial 1- conducted in healthy volunteers trial 2 and 3- tested in patients trial 4- new drug is released to general use

what is the most widely used antibiotic in hospitals?

vancomycin because it can treat C.diff and MRSA