What complication may arise when a drug is not completely dissolved in an intravenous solution?

When a drug is not completely dissolved in an intravenous solution, the formation of particulate matter can lead to serious complications, including the risk of embolism. An embolism occurs when a solid particle or bubble travels through the bloodstream and lodges in a vessel, potentially blocking the flow of blood. This can lead to ischemia and tissue damage, depending on where the embolism occurs, such as in the lungs, brain, or heart.

In the context of intravenous administration, it's critical that medications are fully dissolved to ensure that they can be delivered smoothly and uniformly into the circulation. If undissolved particles are present, they may be introduced directly into the bloodstream, creating the risk of obstructing blood vessels.

Other complications such as hypersensitivity reactions, drug absorption issues, or nephrotoxicity are less likely to be directly caused by undissolved drug particles in the intravenous solution. Hypersensitivity reactions relate more to individual immune responses to a drug, while drug absorption issues pertain more to routes other than IV administration, and nephrotoxicity typically results from drug accumulation in the kidneys rather than particulate matter from IV solutions.