Quick Answer: What Determines The Maximum Response Of A Drug?

What does a Schild plot show?

Schild plot A graph of log (concentration ratio – 1) against log (antagonist concentration).

An example is shown in Fig.


The intercept on the log concentration axis is equal to the pA2 value, while the slope gives information about the nature of the antagonism..

What is the therapeutic value?

The concept of therapeutic value is related to the therapeutic properties of medications, their clinical effectiveness, and health outcomes. When these characteristics are compared with other therapeutic alternatives available in the market, the definition is framed in the concept of added therapeutic value.

What is a competitive agonist?

A full agonist has high efficacy, producing a full response while occupying a relatively low proportion of receptors. … A competitive antagonist binds to the same site as the agonist but does not activate it, thus blocks the agonist’s action.

How do you describe efficacy?

capacity for producing a desired result or effect; effectiveness: a remedy of great efficacy.

Which drug has a high affinity for the receptor?

ClonidineClonidine and Methoxamine are partial agonists. Clonidine has a higher affinity but a lower intrinsic activity than does Methoxamine. Intrinsic activity affects the magnitude of the response. An antagonist that binds to the receptor in a reversible mass-action manner is referred to as a competitive antagonist.

What is maximal response?

MAXIMAL DRUG RESPONSES AND SPARE RECEPTORS As the concentration of a drug in a human organ system increases, the response of that system would be expected to increase until a maximal response is obtained. The level of response is related to the number of receptors occupied.

What determines potency of a drug?

In summary: Potency is the concentration (EC50) or dose (ED50) of a drug required to produce 50% of that drug’s maximal effect. Efficacy (Emax) is the maximum effect which can be expected from this drug (i.e. when this magnitude of effect is reached, increasing the dose will not produce a greater magnitude of effect)

Which drug produces a therapeutic response?

A drug which binds to a receptor and produces a maximum response is called a full agonist; a drug which binds and produces less than a maximal response is called a partial agonist. Drugs which bind but do not activate second messenger systems are called antagonists.

What does it mean to have a high affinity?

High-affinity ligand binding implies that a relatively low concentration of a ligand is adequate to maximally occupy a ligand-binding site and trigger a physiological response. … In the example shown to the right, two different ligands bind to the same receptor binding site.

What is high potency?

The term “high potency” may be used on the label or in labeling of a multi-ingredient product to describe the product (as opposed to describing the level of individual ingredients) if the product contains 100 percent or more of the RDI for at least two-thirds of the vitamins and minerals that are listed in 21 CFR 101.9 …

What are the 4 pharmacokinetic principles?

There are four main components of pharmacokinetics: liberation, absorption, distribution, metabolism and excretion (LADME). These are used to explain the various characteristics of different drugs in the body.

What is a pA2 value?

The value of pA2 is a negative logarithm of the molar concentration of competitive antagonist, which requires a doubling of the concentration of agonist to compensate for the action of the antagonist. The meaning of pA2 is the affinity of the antagonist to the receptor (4).

How do you calculate EC 50?

The EC50 of a graded dose response curve therefore represents the concentration of a compound where 50% of its maximal effect is observed. The EC50 of a quantal dose response curve represents the concentration of a compound where 50% of the population exhibit a response, after a specified exposure duration.

How are doses determined?

Prescription drug dosage is based typically on body weight. Drugs come with a recommended dose in milligrams or micrograms per kilogram of body weight, and that is used in conjunction with the patient’s body weight to determine a safe dosage.

Why is drug efficacy important?

Obviously, a drug (or any medical treatment) should be used only when it will benefit a patient. Benefit takes into account both the drug’s ability to produce the desired result (efficacy) and the type and likelihood of adverse effects (safety).

What does it mean for a drug to be highly protein bound?

Protein binding can enhance or detract from a drug’s performance. … Agents that are highly protein bound may, however, differ markedly from those that are minimally bound in terms of tissue penetration and half-life. Drugs may bind to a wide variety of plasma proteins, including albumin.

What determines drug affinity?

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 mathematical model of affinity of a drug for the receptor was first described by Irving Langmuir Kenakin (2004).

What is the difference between potency and toxicity?

Although toxicological data offer a useful starting point, there is a difference between potency and toxicity. Potency is a measure of how much of the API is required to have a therapeutic effect; toxicity is a measure of its adverse effects.

What is meant by potency?

the state or quality of being potent. power; authority. efficacy; effectiveness; strength. capacity to be, become, or develop; potentiality. a person or thing exerting power or influence.

What is maximal efficacy?

Efficacy: Refers to the relative ability of a drug-receptor complex to produce a maximum functional response. … This maximal effect produced is called maximal efficacy (Emax) and is irrespective of drug concentration.

What is a therapeutic benefit?

Therapeutic effect refers to the response(s) after a treatment of any kind, the results of which are judged to be useful or favorable. This is true whether the result was expected, unexpected, or even an unintended consequence.