A patient has been placed on a milrinone (Primacor) infusion as part of the therapy for end-stage heart failure. What adverse effect of this drug will the nurse watch for when assessing this patient during the infusion?

Correct Answer: D

Rationale: The correct answer is D) Cardiac dysrhythmias. Milrinone is a phosphodiesterase inhibitor that works by increasing intracellular cyclic adenosine monophosphate (cAMP) levels leading to positive inotropic effects on the heart muscle. However, one of the major adverse effects of milrinone is an increased risk of developing cardiac dysrhythmias, such as ventricular arrhythmias, atrial fibrillation, and ventricular tachycardia. These dysrhythmias can be life-threatening and require prompt recognition and intervention. Option A) Hypertension is less likely as milrinone typically causes vasodilation and may actually lower blood pressure. Option B) Hyperkalemia is not a common adverse effect of milrinone infusion. Option C) Nausea and vomiting are possible adverse effects of milrinone, but they are generally not as critical or directly related to the drug's mechanism of action compared to cardiac dysrhythmias. In an educational context, it is essential for nurses and healthcare providers to be knowledgeable about the pharmacological effects and potential adverse reactions of medications used in the treatment of heart failure. Understanding these implications allows for vigilant monitoring, early recognition of adverse effects, and appropriate intervention to ensure patient safety and optimal outcomes.

Correct Answer: D

Rationale: The correct answer is D) Passive diffusion (lipid diffusion). In the context of drug absorption in the gastrointestinal (GI) tract, passive diffusion is the main mechanism through which most drugs are absorbed. This process involves the movement of drugs across the GI epithelium down a concentration gradient, without the need for a carrier or energy input. Lipid-soluble drugs can easily penetrate the lipid-rich cell membrane via passive diffusion, allowing them to be absorbed efficiently. Option A) Active transport (carrier-mediated diffusion) involves the use of specific carrier proteins to transport molecules across the cell membrane against a concentration gradient. While some drugs may utilize active transport mechanisms, it is not the main mechanism for most drugs in the GI tract. Option B) Filtration (aqueous diffusion) refers to the movement of substances through pores or channels in the cell membrane. This mechanism is more relevant in processes like kidney filtration rather than drug absorption in the GI tract. Option C) Endocytosis and exocytosis involve the engulfing of substances into the cell and subsequent release. This mechanism is more commonly seen in the transport of larger molecules or particles rather than small drug molecules. Understanding the mechanisms of drug absorption in the GI tract is crucial in pharmacology as it influences drug bioavailability, onset of action, and overall efficacy. By grasping the concept of passive diffusion as the primary mechanism, healthcare professionals can better predict and optimize drug absorption outcomes for patient care.

Correct Answer: B

Rationale: In the context of pharmacology, understanding the mechanisms of transmembrane signaling is crucial for comprehending how drugs interact with receptors to produce their effects. In this question, option B, "Gene replacement by the introduction of a therapeutic gene to correct a genetic effect," is the correct answer as it does not pertain to transmembrane signaling mechanisms. Option A, "Transmembrane receptors that bind and stimulate a protein tyrosine kinase," is a valid mechanism involving receptor activation leading to kinase activation and subsequent signaling cascades. Option C, "Ligand-gated ion channels that can be induced to open or close by binding a ligand," describes another common mechanism where ligand binding induces conformational changes in ion channels leading to changes in cellular excitability. Option D, "Transmembrane receptor protein that stimulates a GTP-binding signal transducer protein (G-protein) which in turn generates an intracellular second messenger," represents a classic G-protein coupled receptor (GPCR) signaling pathway involving second messenger production. Educationally, understanding these mechanisms is essential for students and healthcare professionals to grasp how drugs targeting these signaling pathways elicit their pharmacological effects. This knowledge is fundamental for drug development, patient care, and understanding the underlying mechanisms of various cardiovascular drugs.

Correct Answer: C

Rationale: In this scenario, the correct answer is C) Motor function. The question is related to the order in which functions are blocked by certain pharmacological interventions. The rationale behind this is that in the context of pharmacology, motor function is typically the last to be affected when compared to pain, temperature, muscle spindles, touch, and pressure. This is because motor function is controlled by a more complex neural network and is generally more resilient to pharmacological interventions compared to other sensory functions. Now, let's discuss why the other options are incorrect: A) Pain, temperature: Pain and temperature sensations are usually among the first functions to be affected by pharmacological interventions due to their direct connection to sensory nerves that are more sensitive to changes in their environment. B) Muscle spindles: Muscle spindles are sensory receptors located within muscles that are responsible for detecting changes in muscle length and tension. These are typically more sensitive to pharmacological interventions compared to motor function. D) Touch, pressure: Touch and pressure sensations are also usually affected before motor function due to their direct sensory input and connection to peripheral nerves. In an educational context, understanding the order in which different functions are affected by pharmacological interventions is crucial for healthcare professionals when assessing patients for potential side effects or complications related to drug therapy. This knowledge helps in predicting and managing adverse effects and optimizing patient care.

Correct Answer: C

Rationale: In this case, the correct answer is C) Edrophonium. Edrophonium is a short-acting cholinesterase inhibitor used to reverse the effects of nondepolarizing neuromuscular relaxants like tubocurarine. Physostigmine (option B) is primarily used to treat anticholinergic toxicity and has limited effectiveness in reversing neuromuscular blockade. Echothiophate (option A) is used in the treatment of glaucoma. Pilocarpine (option D) is used to treat conditions like glaucoma and xerostomia, and is not indicated for reversing neuromuscular blockade. Understanding the correct drug for reversing the effects of nondepolarizing neuromuscular relaxants is crucial in clinical practice, especially in scenarios like anesthesia and critical care where these drugs are commonly used. Edrophonium's rapid onset and short duration of action make it an ideal choice for quickly assessing and reversing neuromuscular blockade to prevent complications like residual muscle weakness post-surgery. This knowledge is essential for healthcare professionals to ensure patient safety and optimal outcomes.