Pharmacology and Medicinal Chemistry of Pain, Analgesic, Anti-inflammatory and Antipyretic Drugs

Dedication

Science has evident that, a mother feels extreme pain during childbirth, generally described as a combination of strong cramping, tightening, and pressure, with some women comparing it to extreme menstrual cramps, bad back pain, or a broken bone. As labor progresses, contractions become more intense, longer, and closer together,labor feels like the worst pains someone can ever imagine, followed by mothers butt feeling like it's going to explode or basically split open. A mother bear this much pain just to bring her child to the earth.

This is just to illustrate the extent to which a mother loves her child! 'Love your mom till the end of your life. The lady with whom you fight almost every day, suffered so much pain just to give you a beautiful life!

This chapter on pain and pain management is dedicated to all beloved mothers without their tolerance and affection, the world doesn’t become so much beautiful. 

Pain 

Pain, in the sense of physical pain, is a typical sensory experience that may be described as the unpleasant awareness of a noxious stimulus or bodily harm. Individuals experience pain by various daily hurts and aches, and sometimes through more serious injuries or illnesses. For scientific and clinical purposes, pain is defined by the International Association for the Study of Pain (IASP) as "an unpleasant sensory and emotional experie        nce associated with actual or potential tissue damage, or described in terms of such damage". Pain begins when local tissue damage, a noxious stimuli stimulate inflammatory process that release inflammatory substances, such as-Prostaglandins, Serotonin, Bradykinin, Histamines etc.

In medicine, pain is considered as highly subjective. A definition that is widely used in nursing was first given as early as 1968 by Margo McCaffery: "Pain is whatever the experiencing person says it is, existing whenever he says it does". Pain of any type is the most common reason for physician consultation in the United States, prompting half of all Americans to seek medical care annually. It is a major symptom in many medical conditions, significantly interfering with a person's quality of life and general functioning. Diagnosis is based on characterizing pain in various ways, according to duration, intensity, type (dull, burning, throbbing or stabbing), source, or location in body. Usually pain stops without treatment or responds to simple measures such as resting or taking an analgesic, and it is then called ‘acute’ pain. But it may also become intractable and develop into a condition called chronic pain, in which pain is no longer considered a symptom but an illness by itself. The study of pain has in recent years attracted many different fields such as pharmacology, neurobiology, nursing, dentistry, physiotherapy, and psychology. Pain medicine is a separate subspecialty figuring under some medical specialties like anesthesiology, physiatry, neurology, and psychiatry.

Pain is part of the body's defense system, triggering a reflex reaction to retract from a painful stimulus, and helps adjust behavior to increase avoidance of that particular harmful situation in the future. Given its significance, physical pain is also linked to various cultural, religious, philosophical, or social issues.

Analgesic drugs 

An analgesic (also known as a painkiller) is any member of the diverse group of drugs used to relieve pain (achieve analgesia). The word analgesic derives from Greek an- ("without") and algos ("pain"). Analgesic drugs act in various ways on the peripheral and central nervous systems; they include paracetamol (acetaminophen), the non-steroidal anti-inflammatory drugs (NSAIDs) such as the salicylates, narcotic drugs such as morphine, synthetic drugs with narcotic properties such as tramadol, and various others.

In choosing analgesics, the severity and response to other medication determines the choice of agent; the WHO pain ladder, originally developed in cancer-related pain, is widely applied to find suitable drugs in a stepwise manner. 

The analgesic choice is also determined by the type of pain: for neuropathic pain, traditional analgesics are less effective, and there is often benefit from classes of drugs that are not normally considered analgesics, such as tricyclic antidepressants and anticonvulsants.