How does a drug reach its target?

How does a drug reach its target?

To elicit an effect on its target, a drug must be absorbed and then distributed to its binding site before being metabolized and excreted. These pharmacokinetic processes affect the amount of free drug that ultimately will reach its binding site on a receptor.

What is the pharmacokinetic process?

The pharmacokinetic process is concerned with the absorption, distribution, and elimination (by metabolism and excretion) of drugs. It is evident that drug molecules have to pass many structural and metabolic barriers.

What is pharmacokinetics of a drug?

Pharmacokinetics is currently defined as the study of the time course of drug absorption, distribution, metabo- lism, and excretion. Clinical pharmacokinetics is the application of pharmacokinetic principles to the safe and effective therapeutic management of drugs in an individual patient.

What is drug distribution?

Drug distribution is the disbursement of an unmetabolized drug as it moves through the body’s blood and tissues. The efficacy or toxicity of a drug depends on the distribution in specific tissues and in part explains the lack of correlation between plasma levels and the effects that are seen.

Where does drug distribution occur?

The drug is easily distributed in highly perfused organs such as the liver, heart and kidney. It is distributed in small quantities through less perfused tissues like muscle, fat and peripheral organs.

How does route of administration affect bioavailability?

By definition, when a medication is administered intravenously, its bioavailability is 100%. However, when a medication is administered via routes other than intravenous, its bioavailability is generally lower than that of intravenous due to intestinal endothelium absorption and first-pass metabolism.

Which pharmacokinetic parameter relates to the movement of a drug from its site of administration to the systemic circulation?

Absorption
Absorption is the process that brings a drug from the administration, e.g., tablet, capsule, into the systemic circulation. Absorption affects the speed and concentration at which a drug may arrive at its desired location of effect, e.g., plasma.

What is pharmacokinetics and how does this impact medication prescribing?

Pharmacokinetics describes how a drug moves into, through and out of the body, tracking its absorption, distribution, metabolism and excretion (or ADME, for short), which together control the concen- tration of the drug in the body over time (see Table 1).

Is administration a part of pharmacokinetics?

Drug administration is the giving of a drug by one of several means (routes). Drug kinetics (pharmacokinetics) describes how the body handles a drug and accounts for the processes of absorption, distribution, metabolism, and elimination.

How is medication distributed in the body?

Distribution in pharmacology is a branch of pharmacokinetics which describes the reversible transfer of a drug from one location to another within the body. Once a drug enters into systemic circulation by absorption or direct administration, it must be distributed into interstitial and intracellular fluids.

How is drug distribution determined?

Volume of distribution (Vd), represents the apparent volume into which the drug is distributed to provide the same concentration as it currently is in blood plasma. It is calculated by the amount of the drug in the body divided by the plasma concentration [19].

Where is the main route of drug elimination?

Renal excretion is the most common route of drug elimination. However, many drugs are excreted into bile via the liver and some volatile substances (primarily gaseous anesthetics) can be excreted via the lungs.