a) A reduction in the dosage of the drugs The liver is the primary site of drug metabolism. Patients with severe liver damage, such as that caused by cirrhosis, will require reductions in drug dosage because of the decreased metabolic activity. Even with decreased dosage, more frequent monitoring is required to detect adverse drug effects that may be related to impaired metabolism. A change in the timing (e.g., lengthening time between doses) may be needed for some drugs, but not all, and a drug dosage that is too large for the liver to metabolize may still cause harm even if doses are spaced further apart. The nurse is discussing how the body handles medications after administration. Which process should the nurse include in the discussion? (Select all that apply.) A. A. The processes of pharmacokinetics are grouped into four categories: absorption,
distribution, metabolism, and excretion. All four of these processes have drug movement in common. Ingestion refers to oral administration of medications, which occurs prior to pharmacokinetic processes. The nurse is reviewing medications and their effects on the body. Which process should the nurse identify that describes how drugs move into their target cells? (Select all that apply.) A. A. Drugs use two primary processes to cross membranes: diffusion and active transport. Absorption and metabolism are pharmacokinetic processes that occur after the medication has been administered. Capillary blockade is a mode of bodily uptake for radioactive tracers. A client is prescribed a drug that does not need to enter the body cells to be effective. In which way should this drug produce physiologic effects? A. C. Drugs may not need to enter the cell to produce their effects. Once bound to receptors, located on the plasma membrane, some drugs activate second messengers within the cell, which produce physiologic changes. These drugs do not diffuse through body fluids, alter the chemistry of blood cells, or stimulate white blood cells to transport the drug to the body site. The nurse is discussing pharmacokinetics with a group of colleagues. Which type of drug molecule should the nurse explain that moves through the cell membrane by simple diffusion? (Select all that apply.) A. A. Drug molecules that are small, nonionized, and lipid soluble will usually pass through plasma membranes by simple diffusion and easily reach the target cells. Ionized drugs and water-soluble agents have difficulty crossing plasma membranes by simple diffusion. These agents may require a carrier, or transport proteins to cross membranes The nurse is planning to administer medications to a client. Which factor should the nurse expect when cells use active transport to move drugs into the cells? A. C. Some drugs cross membranes against their gradient, from low concentration to high concentration, through the process of active transport. This requires expenditure of energy on the part of the cell. A carrier protein. Ionization, water-solubility, or open channels in the plasma membrane are not required for active transport. A client has a body temperature of 102° F. Which form of acetaminophen should the nurse request to increase the absorption rate? A. A. Tablets and capsules must dissolve before the medication is available for absorption. Because oral liquid formulations do not undergo dissolution, they are absorbed faster than capsules, uncoated tablets, and enteric-coated tablets. The nurse prepares medications for a client. For which reason should the nurse expect the client to have difficulty absorbing medications? A. D. Absorption of medications affected by digestive motility. Changes in gastrointestinal motility may either speed up or slow down absorption, depending on the drug and where it is absorbed. Elevated blood pressure, decreased cardiac output, or elevated blood
glucose do not affect the absorption of medications. The nurse is considering routes of administration prior to administering a medication to a client. Which route should the nurse expect to have the fastest level of effectiveness? (Select all that apply.) A. A. Drugs administered intravenously (IV) or intra-arterially directly enter the bloodstream. This causes rapid absorption to the tissues after the infusion. Drugs administered by the oral, subcutaneous, or intramuscular routes take longer to absorb. A client is prescribed medications to be given through a gastrostomy tube. Which action should the nurse take to ensure the fastest absorption of these medications? A. B. Liquid formulations of an oral drug are absorbed faster than tablets or capsules of the same drug. Crushing the medications together, dissolving the medications in water, or flushing the tube with water after administering will not ensure that
the medications are absorbed faster. The nurse collects health history information from a pregnant client. For which reason should the nurse remind the client to avoid taking any type of medication? A. C. The The nurse is preparing to administer an inhaler to a client. Which factor should the nurse identify that affects respiratory excretion of this medication? (Select all that apply.) A. C. Drugs delivered by gas or volatile liquid are especially suited for excretion by the respiratory system. The rate of respiratory excretion is dependent on factors that affect gas exchange, including diffusion, gas solubility, and blood flow to the lungs. Respiratory excretion is not dependent upon water-solubility of the drug. Transport proteins are involved with movement of some drugs to their target cells, but are not involved with respiratory excretion. A client reports feeling lightheaded and dizzy a few hours after taking an antihypertensive medication. Which classification of medication should the nurse realize the client has been prescribed? A. A. Medications that require metabolism to produce therapeutic action are called prodrugs. Because the medication needs to be converted, effects of the medication will occur hours later. First-pass explains how a drug is metabolized in the liver. Enzyme inducers or enzyme inhibitors would not cause increased symptoms hours after the medication has been administered. A client is prescribed a water-soluble drug. In which body fluid should the nurse expect this medication to be excreted? (Select all that apply.) A. B. Saliva A client who is taking phenobarbital as prescribed has a low blood level of the drug. Which factor should the nurse suspect as the reason for this finding? A. C. Phenobarbital is an enzyme inducer and increases the rate of its own destruction. Because medications will be inactivated at a much faster rate, higher doses may be required to achieve an optimal therapeutic effect for some clients. Phenobarbital does not undergo CYP450 inhibition and is not a prodrug. This is not occurring because the CYP450 enzyme is unable to metabolize phenobarbital. The nurse notices that the response of a medication varies among clients. Which client factor should the nurse identify that affects drug metabolism? (Select all that apply.) A. C. The nurse reviews serum drug levels for a client. Which level should be identified as optimum for the client? A. A. The plasma drug concentration between the minimum effective concentration and the toxic concentration is called the therapeutic range of the drug. This is considered optimum for the client. The toxic concentration is the drug level that will cause serious adverse effects. The minimum effective concentration is the drug level that will cause therapeutic effects. Half-life is the level where the drug is no longer detected in the blood stream. A client asks how long a dose of pain medication will last. Which variable should the nurse review with the client? (Select all that apply.) A. A. Many variables can affect the duration of drug action, including drug concentration, dosage, route of drug administration, The nurse is administering a medication to a client with a half-life of 1 hour. In which time frame should the nurse expect the medication to reach a plateau in the client's body? A. A. Few drugs are administered as a single dose. Repeated doses result in an accumulation of drug in the
bloodstream. Eventually, a plateau will be reached where the level of drug in the plasma is maintained continuously within the therapeutic range. At this level, the amount administered has reached equilibrium with the amount of drug being eliminated, resulting in the distribution of a continuous therapeutic level of drug to body tissues. Theoretically, it takes approximately four half-lives to reach this equilibrium. For a drug with a half-life of 1 hour, it will take 4 hours for a
plateau to be reached. An older client is concerned about receiving "too much" of a medication because another dose was given shortly after a large initial dose. Which response should the nurse make to this patient? A. A? A loading dose is a higher amount of drug, often given only once or twice to "prime" the bloodstream with a sufficient level of drug. Before plasma levels can drop back toward zero, intermittent maintenance doses are given to keep the plasma drug concentration in the therapeutic range. A maintenance dose was not provided because of the client's age. A loading dose is not used to test for a drug allergy. It is unlikely that the loading dose was ineffective however the maintenance dose will ensure a therapeutic blood level is achieved. A client is prescribed a maintenance dose of a medication after receiving a loading dose. For which reason should the nurse realize the maintenance dose is prescribed? A. D. Maintenance doses are given to keep the plasma drug concentration in the therapeutic range. The loading dose, not the maintenance dose, allows the medication to reach the therapeutic range faster. Maintenance doses do not prevent toxicity, nor do they prevent fluctuation in blood
levels. |