A nurse understands that an anticholinergic drug will produce which of the following effects?

Choice A reason: This is incorrect. SQ (subcutaneous) administration involves injecting a drug into the fatty tissue under the skin. This route is slower than IV or IM administration, as the drug has to diffuse through the tissue before reaching the bloodstream.

Choice B reason: This is incorrect. PO (by mouth) administration involves swallowing a drug and absorbing it through the digestive system. This route is the slowest of all, as the drug has to pass through the stomach and the liver before reaching the bloodstream. The drug may also be affected by the first pass effect, which reduces its bioavailability.

Choice C reason: This is correct. IV (intravenous) administration involves injecting a drug directly into a vein. This route is the fastest of all, as the drug enters the bloodstream immediately and reaches the target site quickly. The drug also has 100% bioavailability, meaning none of it is lost or degraded.

Choice D reason: This is incorrect. IM (intramuscular) administration involves injecting a drug into a muscle. This route is faster than SQ or PO administration, as the drug can be absorbed by the capillaries in the muscle. However, it is still slower than IV administration, as the drug has to cross the muscle membrane before reaching the bloodstream.

Choice A reason: The initial phase of drug distribution is not the correct definition of the term 'first pass effect'. Drug distribution is the process by which a drug moves from the bloodstream to the tissues and organs of the body. The initial phase of drug distribution is influenced by factors such as blood flow, tissue permeability, plasma protein binding, and tissue binding. The first pass effect is not related to drug distribution, but to drug metabolism, which is the chemical transformation of a drug in the body.

Choice B reason: The rapid absorption of a drug in the intestine is not the correct definition of the term 'first pass effect'. Drug absorption is the process by which a drug enters the bloodstream from the site of administration. The rapid absorption of a drug in the intestine depends on factors such as the drug formulation, the pH of the gastrointestinal tract, the presence of food or other drugs, and the surface area and motility of the intestine. The first pass effect is not related to drug absorption, but to drug metabolism, which is the chemical transformation of a drug in the body.

Choice C reason: The initial rapid excretion of a drug through the urinary system is not the correct definition of the term 'first pass effect'. Drug excretion is the process by which a drug or its metabolites are eliminated from the body. The initial rapid excretion of a drug through the urinary system is influenced by factors such as the renal blood flow, the glomerular filtration rate, the tubular secretion and reabsorption, and the urine pH. The first pass effect is not related to drug excretion, but to drug metabolism, which is the chemical transformation of a drug in the body.

Choice D reason: The metabolism of a drug before it reaches the systemic circulation is the correct definition of the term 'first pass effect'. Drug metabolism is the process by which a drug is chemically transformed in the body, usually by enzymes in the liver or other tissues. The first pass effect is a phenomenon of drug metabolism that occurs when a drug is administered orally and passes through the gastrointestinal tract and the liver before reaching the systemic circulation. The first pass effect can reduce the bioavailability and the effectiveness of the drug, as some or most of the drug may be metabolized and inactivated before reaching the site of action.