03 Nov

How do Pain Killers analgesics works – AC

Although everyone in this entire world understand that what is pain. But still it is so difficult to define it. It is usually a protective brain mechanism to alert your brain that damage is occurred (when it does). To get a relief from this pain, we usually use painkillers and analgesics to actually numb our brain for the pain effect.

Analgesics also known as pain killers or pain relievers are medications that are meant mainly to relief pain temporarily  but they do not treat the main cause of the pain. Pain syndromes are dissimilar and they vary by how they are inflicted to the nervous system the only factor that unites pain is their transmission from the affected organ to the brain.

Analgesics work at the level of the nervous system either by blocking the pain signal from the peripheral nervous system or by changing the interpretation by the nervous system.

Choices on the type of analgesic to use is mainly based on  the consideration of the risk or benefit factors of the drugs in question , the type of pain one is experiencing, severity of one’s pain and finally  the  risk of adverse effects. We tend to go for drugs that have the least risk to us.


Analgesics work with cells, body's nerve endings, nervous system, and the brain to refrain the pain sensation from you. When cells in your body are injured or damaged, they release chemicals called prostaglandins. The nerve endings that are pain sensors, are very sensitive to this chemical. When prostaglandin is released, the nerve endings respond to it by picking up and transmitting the pain and injury messages through the nervous system to the brain. After this we feel pain.

Analgesics either block up the production of prostaglandins or cause a state of numbness to kill the sensation of pain.


Non-Steroidal Anti inflammatory Drugs work by reducing the inflammations. They do this by producing prostaglandins from the damaged tissues by blockage of the enzyme cyclooxygenase {COX}. 

They are characterized as peripherally acting analgesics, as they have no effect on the symptom of pain.

Some of the commonly known NSAIDs are:

  • Aspirin (acetylsalicylic acid)
  • Diclofenac
  • Etodolac
  • Tolfenamic acid
  • Oxaprozin
  • Flufenamic acid
  • Dexibuprofen
  • Indomethacin.

COX-2 Inhibitors (Coxibs)

COX-2 Inhibitors are also categorized in NSAID but they work differently. They directly target cyclooxygenase-2 which is  an enzyme responsible for  pain and inflammation. COX-2 inhibitors do no interfere with COX-1. This enzyme is present in nearly every body tissues. It plays a significant role in the functioning of the gastrointestinal tract, kidneys and platelets. COX-2 is produced mainly in response to inflammation. Some COX-2 inhibitors are prescribed  to treat pain after surgery.

Researches have found that COX-2 inhibitors have some side effects which are

  • non-fatal myocardial infractions and non-fatal stroke.
  • They may also result to death from vascular events such as myocardial infarction or stroke.
  • They are also said to be associated with cancer and Neuropsychiatric disorders.

Narcotic analgesics

Narcotic analgesics are drugs that relieve pain and can cause numbness and even lead to a state of unconsciousness.

Narcotic analgesics reduce neuronal excitability in the pain carrying pathway by attaching themselves to opioid receptors which are found  in the central and peripheral nervous system. They can be used to relieve both acute and chronic/sever pain. They also have the tendency to cause tolerance and dependence, they have a high potential for misuse, abuse, and diversion.

Examples of Narcotic analgesics are:

  •     Codeine
  •     Hydrocodone
  •     Oxycodone
  •     Methadone
  •     Hydromorphone
  •     Morphine
  •     Fentanyl.

The side effects of Narcotic analgesics include:

  •     Constipation
  •     Nausea
  •     Dizziness
  •     Sedation
  •     Headache
  •     dry mouth
  •     respiratory problems
  •     chest pains
  •     abnormal heart beats.

Compound Analgesics

The compound analgesic or pain killers contains a combination of analgesics with other medicines in a single tablet. A combination is mostly beneficial when its components go through different analgesic mechanisms.

The commonly used types of Compound Analgesics are

  •     Paracetamol
  •     Aspirin
  •     Codeine
  •     Amlodipine+Olmesartan
  •     Dihydrocodeine.

Analgesics Side Effects

Looking at it from a vast perspective each group of Analgesics have their own side effects.  Thus from a general point of view the most common side effect of Analgesics are;

  • Nausea and vomiting
  • Reduced concentration or confusion
  • Difficulty in breathing
  • Drowsiness and dizziness
  • Dry skin
  • Addiction
  • Allergic reactions
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