Which phase of pharmacokinetics involves the movement of a drug from its site of administration to the bloodstream?

Choice A reason: Vasoconstriction is the desired therapeutic effect of phenylephrine in this context. Phenylephrine is a medication that stimulates the alpha1 receptors on the blood vessels, causing them to constrict or narrow. This increases the resistance to blood flow and raises the blood pressure. Phenylephrine is used as a vasopressor to treat hypotension, which is a condition of low blood pressure that can cause dizziness, fainting, or organ damage. The nurse should monitor the blood pressure and the peripheral pulses of the patient after administering phenylephrine.

Choice B reason: Bronchodilation is not the desired therapeutic effect of phenylephrine in this context. Phenylephrine is a medication that stimulates the alpha1 receptors on the blood vessels, causing them to constrict or narrow. It has no effect on the beta2 receptors on the bronchial smooth muscle, which are responsible for bronchodilation or widening of the airways. Phenylephrine is not used to treat respiratory conditions, such as asthma or chronic obstructive pulmonary disease, that cause bronchoconstriction or narrowing of the airways. The nurse should assess the respiratory rate and the breath sounds of the patient after administering phenylephrine.

Choice C reason: Diuresis is not the desired therapeutic effect of phenylephrine in this context. Phenylephrine is a medication that stimulates the alpha1 receptors on the blood vessels, causing them to constrict or narrow. It has no effect on the kidney function or the urine output. Phenylephrine is not used to treat fluid retention or edema, which are conditions of excess fluid in the body that can cause swelling, weight gain, or heart failure. The nurse should measure the urine output and the specific gravity of the patient after administering phenylephrine.

Choice D reason: Decreased heart rate is not the desired therapeutic effect of phenylephrine in this context. Phenylephrine is a medication that stimulates the alpha1 receptors on the blood vessels, causing them to constrict or narrow. It has little or no effect on the beta1 receptors on the heart, which are responsible for increasing the heart rate and the contractility. Phenylephrine may actually cause a reflex bradycardia, which is a slow heart rate that occurs when the baroreceptors in the blood vessels sense an increase in blood pressure and send signals to the brain to lower the heart rate. Phenylephrine is not used to treat tachycardia, which is a fast heart rate that can cause palpitations, chest pain, or arrhythmias. The nurse should monitor the electrocardiogram and the heart rate of the patient after administering phenylephrine.

Choice A reason: Administering half of the scheduled dose of Colace is not the correct action for the nurse who is caring for a patient who had two loose stools during the night shift. Colace is the brand name of docusate, which is a stool softener that works by increasing the amount of water and fat in the stool, making it easier to pass. Colace is used to treat and prevent constipation, which is a condition of infrequent or hard bowel movements. Colace is not indicated for diarrhea, which is a condition of frequent and loose bowel movements. Administering half of the scheduled dose of Colace may not be enough to prevent constipation, and it may also worsen diarrhea by adding more water and fat to the stool.

Choice B reason: Administering the scheduled dose of Colace is not the correct action for the nurse who is caring for a patient who had two loose stools during the night shift. Colace is the brand name of docusate, which is a stool softener that works by increasing the amount of water and fat in the stool, making it easier to pass. Colace is used to treat and prevent constipation, which is a condition of infrequent or hard bowel movements. Colace is not indicated for diarrhea, which is a condition of frequent and loose bowel movements. Administering the scheduled dose of Colace may not be necessary to prevent constipation, and it may also worsen diarrhea by adding more water and fat to the stool.

Choice C reason: Inserting a rectal tube to prevent excoriation is not the correct action for the nurse who is caring for a patient who had two loose stools during the night shift. A rectal tube is a device that is inserted into the rectum and connected to a drainage bag, which collects the stool and prevents leakage and skin irritation. A rectal tube is used for patients who have fecal incontinence, which is the inability to control bowel movements. A rectal tube is not indicated for patients who have diarrhea, which is a condition of frequent and loose bowel movements. Inserting a rectal tube may not be effective to prevent excoriation, and it may also cause complications such as infection, bleeding, or perforation.

Choice D reason: Holding the scheduled dose of Colace and notifying the ordering physician is the correct action for the nurse who is caring for a patient who had two loose stools during the night shift. Colace is the brand name of docusate, which is a stool softener that works by increasing the amount of water and fat in the stool, making it easier to pass. Colace is used to treat and prevent constipation, which is a condition of infrequent or hard bowel movements. Colace is not indicated for diarrhea, which is a condition of frequent and loose bowel movements. Holding the scheduled dose of Colace may be appropriate to avoid further diarrhea, and notifying the ordering physician may be necessary to determine the cause and the treatment of diarrhea