A drug may be classified by the chemical type of the active ingredient or by the way it is used to treat a particular condition. Each drug can be classified into one or more drug classes.
Narcotic analgesics are drugs that relieve pain, can cause numbness and induce a state of unconsciousness.
They work by binding to opioid receptors, which are present in the central and peripheral nervous system. There are three types of opioid receptors, which are all G-protein linked and either facilitate opening of potassium channels (causing hyperpolarization) or inhibit calcium channel opening (so inhibits release of excitatory neurotransmitters such as substance P). Overall, narcotic analgesics reduce neuronal excitability in the pain carrying pathway.
Morphine and its analogues, and some synthetic derivatives are classed as narcotics analgesics. Narcotic analgesics are used to relieve acute and chronic, severe pain. Some narcotics are more potent than others. They also have the tendency to cause tolerance and dependence.
