Ans. Pharmacology is the branch of science that deals with the interaction of drugs with living organisms. Or the study of pharmacokinetics or pharmacodynamics.
Ans. A drug is any chemical entity that causes a change in biological function in a living organism. Some drugs are formed inside the body such as insulin and noradrenaline etc. drugs that are introduced into the body from outside are called xenobiotic.
Ans. A specific amount of drug prescribed to be taken at one time.
Ans. It is a tight endothelial cells of brain capillaries that doesn’t allow the passage of certain lipid insoluble substances to pass from the blood into the brain. Lipid soluble drugs can easily cross this barrier. Examples of lipid soluble drugs are diazepam, phenobarbital.
Ans. The total volume of body fluid in which a drug appears to be distributed according to its concentration in the blood or plasma.
Ans. It is the weight of drug that produces a certain magnitude of response. For example lesser the weight of drug required to produce a given effect, more its potency. Also more the weight of the drug required to produce the same effect lesser is its potency.
For example clonidine produce its antihypertensive effect in 0.2-0.3mg daily dose while 500-2000mg for methyldopa.
Ans. If the dose of the drug is increased its effect will be increased proportionately, until a stage is reached beyond which there is no further increase in effect even if large dose of drug is given. So this max effect of drug beyond which no further increase in effect occurs even if the large dose of the drug is given is called efficacy.
For example morphine has more efficacy as compared to aspirin used as an analgesic.
Ans. The ration between median toxic dose (TD50) and median effective dose (ED50) is called therapeutic index.
Therapeutic index = TD50/ED50
Ans. An allergic or immunological response to a drug. For example anaphylactic shock with penicillin is a severe type of hypersensitivity reaction.
Ans. Repeated use of drug causes a gradual decrease in the response to a drug. E.g. chronic use of morphine will decrease many of its effects in the body, therefore the dose of the drug has to be increased with the passage of time to maintain the usual effects of the drug.
Ans. It is a rare type of response to a drug that is not related to its dose, that is, even a small dose can cause it.
For example, a rare adverse effect with chloramphenicol is aplastic anemia.
Ans. Drugs may produce two types of effect .i.e useful effects and harmful effects. Harmful effects are also known as adverse drug reaction or undesired effects. These effects may range from mild type of adverse effect to severe effects that may cause a death of the person.
Ans. It is a clinical condition in which there is inadequate supply of blood to tissues.it causes hypotension, oliguria and metabolic acidosis. Common types are:
Ans. Removal of drug from body is known as their excretion. Drugs are excreted from the body either in the form of metabolites or in unchanged form.
Ans. Antidotes is any substance which is used to oppose the effects of poisons without causing any damage to the body.