PHARMACOLOGY

 CUMULATION ::

When the intake of drug exceeds clearance the continuous administration of drug may build up high concentration which may prove toxic This is called cumulation Drugs which cause those effects are digitalis Vit D thyroxine emetine etc Certain metals like arsenic mercury bismuth and lead also slow cumulation 

        To avoid cumulation excretion of drugs should be increased the conditions of liver and kidney should be examined and the drug should be stopped or withheld on appearance of signs and symptoms of toxicity 

Drug-dependence ::

It is the condition characterized by the compulsive use of the drug such that for the individual the effects produced by a drug or the conditions associated with its use are necessary to maintain the optimal state of well being The intensity of dependence may be from a mild desire to a severe craving (psychological dependence or drug habituation ) or associated with withdrawal syndrome (physical dependence or drug -addiction) Psychological dependence is observed with tea coffee tobacco etc Drug addiction is common with alcohol sleeping pills (barbiturates diazepam etc ) opium alkaloids (heroin morphine ) etc