PRINCIPLES OF PHARMACOLOGY, PHARMACODYNAMICS, AND PHARMACOKINETICS MIDTERM QUIZZES PLUS RATIONALES UPDATED QUESTIONS AND CORRECT ANSWERS 100% PASS GUARANTEED WITH DETAILED SOLUTIONS & APPROVED 2024

A patient takes a drug that is metabolized by CYP3A4 isoenzymes. If a CYP3A4 inducing drug is prescribed, what drug adjustment may be necessary to maintain a therapeutic level of CYP3A4 substrate? Increase dosage of the CYP3A4 inducer. Increase dosage of the CYP3A4 substrate. Decrease dosage of the CYP3A4 substrate. Decrease dosage of the CYP3A4 inducer. A drug that acts as an inducing agent for an enzyme system increases the metabolism of drugs metabolized by that enzyme system, thereby lowering the level of those drugs in the body and requiring higher doses to maintain drug effectiveness. Although decreasing the dosage of the drug that induces metabolism may seem reasonable at first glance, this may decrease the therapeutic level of the drug making it ineffective in treating the condition for which it was prescribed. A patient reports that Brand X tablets work faster than Brand Y tablets of the same amount of the same drug. Which statement informs the prescriber’s response when explaining this phenomenon to the patient? Because the drug preparations are chemically equivalent, the actions of the two brands must be identical. Advertising by pharmaceutical companies can enhance patient expectations of one brand over another, leading to a placebo effect. The bioavailability of a drug is determined by the amount of the drug in each dose. Inactive ingredients used in composition can result in differing rates of dissolution, which can alter the drug’s onset of action. Even if two brands of a drug are chemically equivalent (i.e., they have identical amounts of the same chemical compound), they can have different effects in the body if they differ in bioavailability. Tablets made by different manufacturers contain different binders and fillers, which disintegrate and dissolve at different rates and affect the bioavailability of the drug. When prescribing lovastatin, what will a provider advise to decrease the risk of developing muscle toxicity? Avoid exercise for 2 hours after administration. Monitor aspartate aminotransferase (AST) and alanine aminotransferase (ALT). Substitute grapefruit juice with orange juice. Take the medication with an NSAID or other anti-inflammatory drug. Grapefruit juice can inhibit the metabolism of certain drugs including statins like lovastatin. The juice raises drug levels decreasing the intestinal metabolism of the drug resulting in increased drug levels which increases the risk for adverse effects such as muscle toxicity. Taking the drug with an anti-inflammatory drug and avoiding exercise after administration are not supported by science. Monitoring AST and ALT detects liver toxicity, not muscle toxicity. A drug can cause symptoms that resemble those of Parkinson disease. What action should the prescriber take to minimize the potential patient risk? Explain that these are teratogenic effects that must be reported immediately. Order an evaluation of the patient’s genetic predisposition to these effects. Thoroughly educate the patient about recognizing such symptoms and the need to notify the office immediately. Educate the patient about these symptoms and provide reassurance that the condition is expected. Some drugs can cause iatrogenic conditions, which are conditions whose symptoms are the same as those of a known disease. The patient should be prepared for this possibility and be prepared to recognize and report the symptoms immediately. Such effects are not teratogenic, since teratogenic effects affect the fetus. Patients with a genetic predisposition to respond differently to drugs are known to have idiosyncratic effects. Although reassurance may dispel some fear on the part of the patient, it does provide the patient with actions (e.g., notifying the provider) that can allow for symptom management. A patient receiving intravenous gentamicin has a toxic serum drug level. The prescriber confirms that the dosing is correct. Which possible cause of this situation will the provider explore? Whether a loading dose was administered If the ordered dose frequency is longer than the gentamicin half-life Whether patient is taking a medication that binds to serum albumin If the drug was completely dissolved in the IV solution Gentamicin binds to albumin, but only weakly, and in the presence of another drug that binds to albumin, it can rise to toxic levels in blood serum. A loading dose increases the initial amount of a drug and is used to bring drug levels to the desired plateau more quickly. A drug that is not completely dissolved carries a risk of causing embolism but this addresses a different concern. A drug given at a frequency longer than the drug half-life will likely be at subtherapeutic levels and not at toxic levels. An older adult patient is admitted to the hospital for treatment of an exacerbation of a chronic illness. Admission laboratory work reveals an extremely low serum drug level of the drug used to treat this condition. The patient’s renal and hepatic function tests are normal. What might the provider suspect as a likely cause of this finding? Increased tolerance to the drug’s effects Concurrent administration of two highly protein-bound drugs Chronic constipation Nonadherence to the medical regimen Nonadherence is the most common cause of a subtherapeutic drug level. For example, older adult patients who have financial concerns about paying for medications often take less of the drug or take it less often to make the drug last longer. Chronic constipation would be more likely to cause a slight elevation of drug level due to the prolonged time for drug absorption. A patient with increased tolerance to a drug’s effects would require more of the drug to get effects. Concurrent administration of two highly protein-bound drugs would result in increased serum levels of one or both drugs