Selectivity is the degree to which a drug acts on a given site relative to other sites . Relatively nonselective drugs affect many different tissues or organs. For example, atropine, a drug given to relax muscles in the digestive tract, may also relax muscles in the eyes and in the respiratory tract.
What does selective mean in pharmacology?
[sĕ-lek-tiv ́ĭ-te] in pharmacology, the degree to which a dose of a drug produces the desired effect in relation to adverse effects .
How is drug selectivity determined?
Selectivity is defined as the ratio of the affinity of the compound towards the off-target protein relative to the target protein (K d ratio = K d , off target /K d , target ). The larger the K d ratio, the better the selectivity.
What is a drug specificity?
drugs. Specificity is the measure of a receptors ability to respond to a single ligand (1-5) . Low specificity generally results in physiological responses not targeted or intended by. the drug and side effects provide a good example. Indeed, it is not uncommon for a drug.
What is affinity of drug?
Affinity can be defined as the extent or fraction to which a drug binds to receptors at any given drug concentration or the firmness with which the drug binds to the receptor. ... The strength of the binding (interaction) of a ligand and its receptor can be described by affinity.
What are the 4 categories of drug actions?
There are four types of ligand that act by binding to a cell surface receptor, agonists, antagonists, partial agonists, and inverse agonists (Figure 1).
What is the difference between drug selectivity and specificity?
For example a selective drug would have the ability to discriminate between, and so affect only one cell population, and thereby produce an event. Specificity, a term most often confused with selectivity, will be used to describe the capacity of a drug to cause a particular action in a population.
What does it mean when a drug is non selective?
Selectivity is the degree to which a drug acts on a given site relative to other sites. Relatively nonselective drugs affect many different tissues or organs. For example, atropine, a drug given to relax muscles in the digestive tract, may also relax muscles in the eyes and in the respiratory tract.
How can a drug be promiscuous?
Promiscuity is defined as the property of a drug to act with multiple molecular targets and exhibit distinct pharmacological effects. Promiscuous drugs are the basis of polypharmacology and the causes for side effects and unsuitable DMPK.
What is a pharmacodynamic drug?
Pharmacodynamic drug-drug interactions (DDIs) occur when the pharmacological effect of one drug is altered by that of another drug in a combination regimen . DDIs often are classified as synergistic, additive, or antagonistic in nature, albeit these terms are frequently misused.
What does it mean if a drug is potent?
A potent drug is one that will have a very strong effect . For example, some strains of cannabis are more potent than others. When a drug is said to become more or less potent under certain circumstances, this means it becomes stronger or weaker depending on those conditions.
What do you mean by specificity?
: the quality or condition of being specific : such as. a : the condition of being peculiar to a particular individual or group of organisms host specificity of a parasite. b : the condition of participating in or catalyzing only one or a few chemical reactions the specificity of an enzyme.
Is used as adrenergic drug?
Examples of adrenergic drugs which selectively bind to alpha-1 receptors are phenylephrine , oxymetazoline. Selective alpha-2 receptor drugs include methyldopa and clonidine. The key beta-1 selective drug is dobutamine. Lastly, beta-2 selective drugs are bronchodilators, such as albuterol and salmeterol.
What does lower affinity mean?
Low-affinity binding (high K i level) implies that a relatively high concentration of a ligand is required before the binding site is maximally occupied and the maximum physiological response to the ligand is achieved . In the example shown to the right, two different ligands bind to the same receptor binding site.
When can you say that a drug is efficacious?
Specifically, efficacy refers to “ whether a drug demonstrates a health benefit over a placebo or other intervention when tested in an ideal situation , such as a tightly controlled clinical trial.” These studies focus on a primary parameter to be shown statistically different between placebo and intervention groups.
What is drug bioavailability?
More accurately, bioavailability is a measure of the rate and fraction of the initial dose of a drug that successfully reaches either ; the site of action or the bodily fluid domain from which the drug’s intended targets have unimpeded access.[1][2][3] For majority purposes, bioavailability is defined as the fraction of ...
