What is onset of drug action?
the point at which the activity of a drug is apparent, generally measured in terms of the time elapsed between administration and the appearance of its pharmacological effects.
What is meant by drug action?
Drug action refers to all the pharmacokinetic and pharmacodynamic processes involved in producing a drug effect on the disease.
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 duration of action of a drug?
The duration of action of a drug is known as its half life. This is the period of time required for the concentration or amount of drug in the body to be reduced by one-half. We usually consider the half life of a drug in relation to the amount of the drug in plasma.
Which is the major process of absorption for more than 90% of drugs?
Passive diffusion or non-ionic diffusion is considered as the major absorption process for more than 90% of drugs (see figure 3). It is the movement of the drug molecule from a region of higher concentration to a region of lower concentration.
What is the principle of drug action?
The action of drugs on the human body is called pharmacodynamics, and what the body does with the drug is called pharmacokinetics. The drugs that enter the human tend to stimulate certain receptors, ion channels, act on enzymes or transporter proteins. As a result, they cause the human body to react in a specific way.
What is a local drug action?
Local: When the drug is applied locally or directly to a tissue or organ, it may combine with the cell’s membrane or penetrate the cell. General, or systemic: This type of action occurs when the drug enters the bloodstream by absorption or direct injection, affecting tissues and organs not near the site of entry.
What are the types of drug actions?
There are 2 different types of drugs: Agonists – they stimulate and activate the receptors….Potency
- Agonists as having Intrinsic Activity = 1.
- Antagonists as having Intrinsic Activity = 0.
- and, Partial Agonist as having Intrinsic Activity between 0 and 1.
What are the general principles of drug action?
Affinity : The ability of a drug to bind to a receptor. Occupancy : The proportion of receptors to which a drug is bound. Selectivity : Relative affinity or activity of a drug between different receptor types.
What are the five pharmacodynamics processes of drugs?
Pharmacokinetics, sometimes described as what the body does to a drug, refers to the movement of drug into, through, and out of the body—the time course of its absorption, bioavailability, distribution, metabolism, and excretion.
What is a drug half-life?
The half-life of a drug is the time it takes for the amount of a drug’s active substance in your body to reduce by half. This depends on how the body processes and gets rid of the drug. It can vary from a few hours to a few days, or sometimes weeks.
