Conscious sedation: Pharmacology.
Pharmacokinetics and pharmacodynamics.
(1) Different routes of administration
BASIC AND ADVANCED
Pharmacodynamics is the study of how a drug produces its effects on the body. It involves understanding the drug's mechanism of action, the interaction of the drug with its target receptor or enzyme, and the resulting physiological or biochemical changes that occur in the body.
The pharmacokinetic and pharmacodynamic effects of a drug can vary depending on the route of administration. The most common routes of administration for sedation drugs are oral, intravenous (IV), intramuscular (IM), and inhalation.
First pass
When a drug is administered orally, it must first pass through the gastrointestinal tract and liver before entering the bloodstream. This process, called first-pass metabolism, can result in a lower bioavailability of the drug compared to other routes of administration. The onset of action is generally slower, and the peak effects are usually reached later than with other routes. The duration of action is generally longer than with other routes of administration.
Bioavailability
IV administration provides the most rapid onset of action because the drug is delivered directly into the bloodstream. The bioavailability is close to 100%, and the drug is not subject to first-pass metabolism. The peak effects are usually reached quickly, and the duration of action is generally shorter than with other routes of administration.
IM administration can provide a more rapid onset of action than oral administration, but it is usually slower than IV administration. The bioavailability is generally higher than oral administration, but lower than IV administration. The duration of action is generally longer than with IV administration.
Inhalation administration can provide a rapid onset of action, similar to IV administration, but the duration of action is usually shorter. The bioavailability can be highly variable and depends on factors such as the depth and rate of breathing, the solubility of the drug in the blood, and the amount of dead space in the respiratory system.