The availability of new and more effective drugs, such as antibiotics and vaccines, which prevent diseases helped increase the average man’s life span and have vastly improved the quality of life.
Drugs can be classified in many ways:
- By the way they are dispensed- Over the counter (OTC) or by prescription
- By the substance from which it is derived- plant mineral or animal
- By their form- capsule liquid or gas and
- By the way they are administered- by mouth, injection, inhalation, or direct application to the skin
Drugs are also classified by their names. All drugs have three names:
- A chemical name that describes the exact structure of the drug
- A generic or proprietary name, which is the official medical name assigned.
A brand or trade name
Anti- infective drugs are classified as antibacterials, antivirals, or antifungals epending on the type of microorganism they combat. Anti- infective drugs interfere selectively with the functioning of a microorganism while leaving the human host unharmed.
Antibacterial Drugs or Antibiotics- sulfa drugs, penicillin cephalosporins and many others – either kill bacteria directly or prevent them from multiplying so that the body’s immune system can destroy invading bacteria. However bacteria in many cases can spontaneously mutate producing strains that are resistant to existing antibiotics.
Antiviral Drugs- Interfere with the life cycle of a virus by preventing its penetration into a host cell or by blocking the synthesis of new viruses. Antiviral drugs may cure, but often only suppress, viral infections; and flare ups of an infection can occur after symptom free periods.
Cardiovascular Drugs- affect the heart and blood vessels and are divide into categories according to function. Antihypertensive drugs reduce blood pressure, by dilating blood vessels and reducing the amount of blood pumped by the heart into the vascular system. Antiarrhythmic rugs normalize irregular heartbeats and prevent cardiac malfunction and arrest.
Drugs that affect the blood- like antianaemic drugs, such as certain vitamins or iron, enhance the formation of red blood cells. Anticoagulants like heparin reduce blood clot formation an ensure free blood flow through the major organs in the body. Thrombolytic drugs dissolve blood clots which can block blood vessels and deprive the heart and brain of blood and oxygen, possibly leading to heart attack or stroke.
Central Nervous System Drugs- drugs that affect the spinal cord and the brain –are used to treat several neurological and psychiatric problems For instance; antiepileptic drugs reduce the activity of overexcited brain areas and reduce or eliminate seizures. Antipsychotic drugs are used to regulate certain brain chemicals called neurotransmitters which do not function properly in people with psychoses, major mental disorders often characterize by extreme behaviors and hallucination. Antidepressant drugs reduce mental depression. Antianxiety drugs, also referred to as tranquilizers, treat anxiety by depressing the activity in the anxiety centers of the brain.
Analgesic Drugs- Reduce pain and are generally categorized as narcotics and non-narcotics. Narcotics relive pain by acting on specific structures, called receptors, located on the nerve cells of the spinal cord or the brain. Non –narcotic analgesics such as aspirin reduce pain by inhibiting the formation of nerve impulses at the site of pain