Question 1

The nurse is teaching a patient about taking warfarin and asks if the patient takes aspirin. This assessment by the nurse reflects a knowledge of which type of drug interaction?&#10;A) Creation of unique effects&#10;B) Increased therapeutic effects&#10;C) Inhibitory effects&#10;D) Potentiative effects

Accepted Answer

A potentiative effect is one in which one drug intensifies the effects of another. Both warfarin and aspirin suppress blood clotting, and the combination may increase the risk of bleeding, which is an intensified adverse effect. Creation of a unique effect is a rare occurrence in which the combination of two drugs creates a response not seen with either drug when given alone. Increased therapeutic effects are a type of potentiative effect; however, in this case the combination of two drugs would increase the desired effects. An inhibitory effect is a type of pharmacodynamic effect that occurs when an antagonist drug inhibits the action of an agonist drug at the same receptor site.

Question 2

In a discussion of drug-drug interactions, which would be the best example of a beneficial inhibitory interaction?&#10;A) Naloxone (Narcan) blocking morphine sulfate's actions&#10;B) Antacids blocking the action of tetracycline (Sumycin)&#10;C) Alcohol blocking the actions of opioids&#10;D) Cholestyramine blocking the actions of antihypertensive drugs

Accepted Answer

Naloxone is used when a narcotic overdose has occurred. As a narcotic antagonist, it provides a beneficial inhibitory interaction. An antacid blocking tetracycline's antibiotic effects would not be beneficial, but rather detrimental to the desired effects of the tetracycline. Alcohol would not block the effects of opiates, but would contribute to CNS depression. Cholestyramine and certain other adsorbent drugs, which are administered orally but do not undergo absorption, can adsorb other drugs onto themselves, thereby preventing absorption of the other drugs into the blood.

Question 3

A child ingests a parent's aspirin tablets, and the prescriber orders sodium bicarbonate to block the toxic effects of the aspirin. The nurse caring for this patient knows that sodium bicarbonate is effective against the aspirin because it:

A) accelerates its passage through the intestine.
B) alters urinary pH to enhance renal excretion.
C) induces CYP isozymes to increase drug metabolism.
D) raises the pH of the interstitial fluid to facilitate passage out of the cells.

Accepted Answer

Sodium bicarbonate increases the pH of interstitial fluid and plasma, allowing the acidic aspirin ions to move outside the cells and thus removing them from the site where they have toxic effects. It does not have laxative effects and does not alter the rate of passage through the gut. It is not a CYP isozyme inducer and therefore has no effect on drug metabolism. It does not alter renal excretion of aspirin.

Question 4

The nurse is administering morning medications. The nurse gives a patient multiple medications, two of which compete for plasma albumin receptor sites. As a result of this concurrent administration, the nurse can anticipate that what might occur? (Select all that apply.)

A) Binding of one or both agents is reduced.
B) Plasma levels of free drug will rise.
C) Plasma levels of free drug will fall.
D) The increase in free drug can intensify effects.
E) The increase in bound drug can intensify effects.

Accepted Answer

When two drugs bind to the same site on plasma albumin, coadministration of those drugs produces competition for binding. As a result, binding of one or both agents is reduced, causing plasma levels of free drug to rise. The increase in free drug can intensify the effect, but it usually undergoes rapid elimination. The increase in plasma levels of free drug is rarely sustained.

Question 5

Which statement about food and drug interactions is true?&#10;A) Foods alter drug absorption and metabolism but not drug action.&#10;B) Medications are best absorbed on an empty stomach.&#10;C) Patient discomfort is the food and drug interaction of most concern.&#10;D) Some foods can inhibit CYP isozymes and alter drug metabolism.

Accepted Answer

Grapefruit juice inhibits CYP3A4, which lowers the metabolism of some drugs, leading to toxic effects of drugs affected by these isozymes. Foods can alter all pharmacokinetic and pharmacodynamic processes. Not all medications are absorbed better on an empty stomach; some require certain foods to enhance absorption. Patient comfort is a concern, but it is not as important as more severe and possibly life-threatening food and drug interactions.

Question 6

The nurse is providing multiple medications to a patient whose spouse brings him grapefruit juice every morning. The nurse should be concerned about which classes of drugs? (Select all that apply.)&#10;A) Calcium channel blockers&#10;B) Selective serotonin reuptake inhibitors&#10;C) Aminoglycosides&#10;D) Beta blockers&#10;E) Penicillins

Accepted Answer

Calcium channel blockers and selective serotonin reuptake inhibitors have been shown to reach increased and/or toxic levels when taken with grapefruit juice. Grapefruit juice is not contraindicated with aminoglycosides, beta blockers, or penicillins.

Question 7

A nurse is teaching a patient about a prescription for a monoamine oxidase (MAO) inhibitor for depression. What will the nurse teach the patient to avoid while taking this drug?&#10;A) Alcoholic beverages&#10;B) Aged cheeses&#10;C) Brussels sprouts and cabbage&#10;D) Grapefruit juice

Accepted Answer

Aged cheeses are rich in tyramine, which interacts with MAO inhibitors to raise blood pressure to life-threatening levels. Patients taking MAO inhibitors should be taught to avoid tyramine-rich foods. Chianti wine contains tyramine, but other alcoholic beverages do not. Brussels sprouts and cabbage are foods rich in vitamin K, which can interfere with the effects of warfarin. Grapefruit juice inhibits CYP3A4 and interferes with the metabolism of many medications.

Question 8

A nurse is caring for a patient who is taking multiple medications. To help ensure that adverse drug reactions are prevented or minimized, the nurse will do which of the following? (Select all that apply.)

A) Ask the patient about over-the-counter medications used.
B) Contact the prescriber to request cytochrome P450 levels.
C) Limit the patient's calcium intake.
D) Obtain a thorough diet history.
E) Request orders for PRN medications to treat any anticipated symptoms of drug interactions.

Accepted Answer

Over-the-counter medications add to drug interactions, and a thorough history of all medications taken by the patient is essential to minimize adverse drug reactions. Cytochrome P450 levels yield important information about a patient's ability to metabolize drugs and can help predict whether drugs will reach toxic levels or be ineffective. A diet history allows providers to anticipate significant known food-drug interactions. Limiting calcium intake is necessary only if the patient is taking drugs known to interact with calcium, such as tetracycline. Asking for PRN medications to treat drug reactions may only compound the risk, because the risk of drug interactions increases with the number of medications taken.

Question 9

A patient is taking drug X and receives a new prescription for drug Y, which is listed as an inducing agent. The nurse caring for this patient understands that this patient may require _____ doses of drug _____.

A) lower; X
B) lower; Y
C) higher; X
D) higher; Y

Accepted Answer

An inducing agent stimulates the synthesis of CYP isozymes, which may increase the metabolism of other drugs as much as two- to threefold, thereby lowering the level of those drugs in the body and requiring higher doses to maintain drug effectiveness.

Question 10

The prescriber has ordered an antibiotic for a patient with a bacterial infection. The nurse provides patient education at discharge and instructs the patient to take the drug on an empty stomach. When should the patient take the drug? (Select all that apply.)

A) 1 hour or more before a meal
B) Only after an 8-hour fast
C) Only after the patient has missed a meal
D) At least 2 hours after a meal
E) Within 12 hours with liquids but not solids

Accepted Answer

The absorption of some drugs can be significantly reduced by food; these drugs should be taken on an empty stomach, which is 1 hour or more before a meal or at least 2 hours after a meal. An 8-hour fast is not necessary; the patient does not need to miss a meal to take the medication; and it is not reasonable to have the patient on thin liquids for 12 hours.

Question 11

A young adult postoperative patient is receiving morphine 2 to 4 mg IV every 2 hours PRN pain. The last dose was 3 mg given 2 hours ago. The patient is asleep, and the nurse notes a heart rate of 86 beats per minute and a respiratory rate of 8 breaths per minute. Which PRN medication will the nurse give this patient?

A) Diphenhydramine (Benadryl) to counter morphine side effects
B) Morphine 4 mg for increased pain, as indicated by tachycardia
C) Naloxone (Narcan) to block the effects of the morphine
D) Nothing at this time, because the patient is resting comfortably

Accepted Answer

The answer of A young adult postoperative patient is receiving...

Question 12

A patient taking oral contraceptives thinks she may be pregnant. As part of this patient's history, what will the nurse ask the patient?&#10;A) &#34;Do you drink grapefruit juice?&#34;&#10;B) &#34;Do you take seizure medication?&#34;&#10;C) &#34;Do you take your contraception with milk?&#34;&#10;D) &#34;Do you use laxatives regularly?&#34;

Accepted Answer

The answer of A patient taking oral contraceptives thinks she...

Deck 6: Drug Interactions