Since there is no certain relation between chemical structure and pharmacological activity therefore, it would be unwise to arrange all drugs on the basis of their structures or origin. Thus, it is better to arrange the drugs according to their medicinal use. Drugs can be classified according to their medicinal uses into two main classes:
I- Pharmacodynamic agents
Drugs that act on the various physiological functions of the body (e.g. general anaesthetic, hypnotic and sedatives, analgesics etc.).
II- Chemotherapeutic agents
Those drugs which are used to fight pathogenic (e.g. sulphonamides, antibiotics, antimalarial, antiviral, anticancer etc.).
Drugs can treat different types of diseases including:-
1- Infectious diseases:
Transmitted from person to person by outside agents, bacteria (pneumonia, salmonella), viruses (common cold, AIDS), fungi (thrush, athletes foot) and parasites (malaria).
1- Infectious diseases:
Transmitted from person to person by outside agents, bacteria (pneumonia, salmonella), viruses (common cold, AIDS), fungi (thrush, athletes foot) and parasites (malaria).
2- Non-infectious diseases:
Disorders of the human body caused by genetic malfunction, environmental factors, stress, old age etc. (e.g. diabetes, heart disease, cancer. Haemophilia, asthma, mental illness, stomach ulcers, arthritis).
Disorders of the human body caused by genetic malfunction, environmental factors, stress, old age etc. (e.g. diabetes, heart disease, cancer. Haemophilia, asthma, mental illness, stomach ulcers, arthritis).
3- Non-diseases:
Alleviation of pain (analgesic), prevention of pregnancy (contraception) and anesthesia.
Alleviation of pain (analgesic), prevention of pregnancy (contraception) and anesthesia.