The Use and Abuse of Drugs

Chemicals which are not made by the organism may be introduced into the body of n organism for a specific effect. These chemicals are called drugs. A drug is an externally administered substance which modifies or affects the chemical reactions of the body. Drugs can be administered orally and, by injection, by applying to the skin or by inhaling.

Drugs may be used for beneficial effects:

  1. As pain killers or pain relief
  • These drugs relieve pain and reduce inflammation
  • It blocks the transmission of pain signals, or suppresses the responsible part of the brain.
  • Eg: aspirin, paracatemol and morphine


  1. As antibiotics (drugs that kill bacteria)
  • These drugs are used as treatments of bacterial infections.
  • It stops the growth of bacteria without damaging body tissues.
  • Eg: penicillin and tetracycline.


  1. As mood influencing chemicals (drugs)
  • These are useful for treating patients with emotional disorders such as depression, stress, etc.
  • These drugs minimize the effects of hormones or neurotransmitters and produce corresponding state of mind.
  • Eg: Antidepressant and stimulants.


  1. As stimulants
  • These chemicals speed up the transmission of nerve impulses
  • Eg: caffeine and nicotine


Drugs of abuse

Drugs of abuse refer to those substances upon which a person may become dependent. While many are aware of the abuse of legal substances like alcohol or illegal drugs like marijuana and cocaine, less well known is the fact that inhalants like household cleaners are some of the most commonly abused substances.

Abuse of heroin

  • Heroin is one of the narcotics drugs made from opium poppy-plant.
  • Used as a sedative and powerful analgesic. Highly addictive (drug dependence), often abused by drug users.

Effects of the abuse of heroin

  • A powerful depressant

It removes feeling of anxiety and creates a sense of well-being

  • Problem of addictions

Heroin is a drug of abuse because it is a drug upon which a person may become dependent.

  • Severe withdrawal symptoms

If the drug is not available or cannot get further supply of drug they suffer severe withdrawal symptoms. Withdrawal symptoms are diarrhea, vomiting, shaking, muscle pains, sweating, fits and coma in severe cases.

  • Associated problems such as crime and infection

Addiction can lead the user into a life of crime to get money to buy the drug. Also associated with a host of social problems such as crime, unemployment, personnel and family problem.


Effect of excessive consumption of alcohol

Excessive consumption of alcohol my affect the body in two different ways.


Moderate amount of alcohol has short term effects on the body

  • it gives the drinker a feeling of relaxation and well being, it reduces anxiety , tension and inhibition (act as depressant)
  • Blood vessels dilate and leading to a flushing and feeling of warm up specially in the skin.

Continuous excessive consumption of alcohol in large amounts leads to the long term effect

  • Leads to stomach ulcers
  • Heart diseases / strokes
  • High blood pressure
  • Alcoholism/ addiction/ dependence/ tolerance


  • Fetal abnormalities and poor physical and mental development of infants.
  • Leads to miscarriages
  • Low birth weight
  • Mental retardation


Effects of tobacco smoke

  1. Effects of nicotine:

Stimulates the brain making the smoker alert and relaxes the muscles then, dulls the brain and senses. Release adrenaline; increase the rate of heartbeat and blood pressure. Clots the blood easily, increasing the risk of blood clots blocking the blood vessels, clotting of the coronary arteries cause heart attack, clotting of the capillaries of the brain cause stroke.


  1. Effects of carbon monoxide:

Reduces the efficiency of the red blood cells to transport oxygen, may cause death.

Increases the rate of the deposition of fatty substances on the inner walls of arteries, causing lumen become narrow. Damages the lining of blood vessels -increasing the tendency of the blood to clot and so block the blood vessels. It is more readily to combine with hemoglobin to form carboxy hemoglobin instead of oxyhaemoglobin.


  1. Effects of tar:

Contains cancer, causing chemicals. Uncontrolled multiplication of cells results in outgrowths or lumps of tissue, blocking off the air sacs, reducing the efficiency for gaseous exchange. Paralyses the cilia from removing dust particles from the lungs and trachea.


Smoking related diseases

  • Lung cancer
  • Chronic bronchitis
  • Emphysema