Analgesics Drug Classification

What is an Analgesic?

In our day-to-day life, we suffer from so many problems, one of which includes some kind of physical pain and to surmount that we end up eating painkillers which are none other than analgesics.

An analgesic in simple words can be explained as a type of pain killer. It is any member of the group of drugs which gives analgesia i.e., the inability to feel pain by using different medication.

They act in various ways on the Peripheral nervous system and central nervous system.  

They are such types of chemical substances that help in reducing or abolishing pain without causing any type of impairment such as unconsciousness, mental confusion, incoordination or paralysis, or some other disturbances of the nervous system.

These Are Generally Of Two Types: -

  1. Non-narcotic (non-addictive) analgesics 

  2. Narcotic drugs  

Non-Narcotic(Non-Addictive) Analgesics

These are those types of analgesics that do not cause any type of addiction after being consumed. Aspirin and paracetamol belong to the class of non-narcotic analgesics.

Aspirin(2-acetoxy benzoic acid) is one of the most familiar examples. It inhibits the synthesis of compounds known as prostaglandins which stimulate inflammation in the tissues and cause pain. The drugs are effective in relieving skeletal pain as that due to arthritis(inflammation of a joint or joints causing pain and/or disability, swelling, and stiffness). Aspirin has also been very popular because it has antipyretic i.e., temperature lowering properties. Nowadays, aspirin is also used in the prevention of heart attack because of its anti-blood clotting action.

In addition, many other potential applications of aspirin presently under investigation, include pregnancy-related complications, viral inflammation in AIDS patients, Alzheimer’s disease, dementia(a progressive decline in cognitive function due to damage or disease in the brain beyond what might be expected from normal ageing, cancer, etc).

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                Ibuprofen                                       Diclofenac sodium                     Naproxen 

The above images show the different alternatives used when there is a lack of aspirin. They are naproxen, ibuprofen, and diclofenac sodium or potassium.


Narcotic Analgesics

Narcotic analgesics are those types of substances or drugs which induce sleep and unconsciousness after being consumed. For example, morphine and its derivatives codeine, heroin, marijuana are used in severe pain as analgesics. These are known to be habit-forming and may alter mood or behaviour in some contexts. When used in medicinal doses, these relieve pain and produce sleep. However, if taken excessively in amount i.e., excessive(poisonous) doses of this stupor(a state of reduced consciousness or sensibility) coma, convulsions and ultimately leading to death. These narcotics are also referred to as opiates because they are obtained from the opium poppy.

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                         Morphine                                  Codeine                                      Heroin

The above image shows the analgesic morphine and its derivatives codeine, heroin which are used in severe pain.

Further Classification Of Analgesics Based On Their “Mechanism Of Action.”

  • Paracetamol (acetaminophen)

  • NSAIDs

  • COX-2 inhibitors

  • Opioids

  • Alcohol

  • Medical cannabis

  • Combinations

  • Alternative medicine

  • Adjuvants

  • Other drugs

Some of which are discussed below: -

1. Paracetamol (Acetaminophen): - Paracetamol is one of the analgesics which is also known as acetaminophen or APAP. It is a type of medication that is used in the treatment of pain and fever.  

2. Opioids: - Opioids are substances that have similar effects on opium. Morphine and its various derivatives are used as narcotic analgesics. 

3. Alcohol: - Alcohol is an organic compound such as ethanol, which contains a hydroxyl functional group(-OH). It has many effects such as biological, mental, and social effects which influence the consequences of using alcohol for pain.  

Side Effects Of Various Analgesics:-

  • Euphoria, dysphoria, agitation, seizures, hallucinations.

  • Lowered blood pressure and heart rate.

  • Muscular rigidity and contractions.

  • Nausea and vomiting. Non-allergic itching.

  • Sexual dysfunction.

  • Urinary retention.

  • Sedation.

  • Dizziness.

  • Nausea.

  • Vomiting.

  • Constipation.

  • Physical dependence.

  • Tolerance.

  • Respiratory depression.

Did You Know?

  1. Aspirin is an important non-narcotic drug. But overdoses of aspirin should be avoided.

  2. Despite the popularity of aspirin, it is supposed to be toxic to the liver. It gets hydrolysed in the stomach giving salicylic acid which sometimes causes bleeding in the stomach. Therefore, over dosage and use of it in an empty stomach should be avoided. 

  3. Calcium and sodium salts of aspirin are more soluble and less harmful.

  4. The type of analgesic that should be used is also determined by the type of pain. For example in neuropathic pain, traditional analgesics that are used are less effective, and there is usually benefit from the classes of drugs that are not normally considered analgesics, like tricyclic antidepressants and anticonvulsants

  5. According to the World Health Organization (WHO), pain ladder specifies mild analgesics as its first step. This is because when choosing analgesics severity and responses to other medication also determines the choice of agent.

FAQ (Frequently Asked Questions)

1. What Is The Difference Between Analgesics And Antipyretics?

The basic difference between analgesics and antipyretics is that analgesics are those chemical substances that give us relief in pain, whereas antipyretics are those chemical substances that reduce body temperature.

Examples of Analgesics: - Aspirin, ibuprofen, diclofenac sodium, naproxen, narcotics(morphine, codeine, heroin).

Examples of Antipyretics: - Aspirin, paracetamol, phenacetin.

2. What Type Of Medications Are Used During Labor And Delivery For Giving Relief?

Generally, there are two types of drugs used for pain relief: 1) analgesics and 2) anesthetics. Analgesics reduce the pain without loss of feeling, or muscle movement. Anesthetics relieve pain by blocking most feelings, including pain. There are various pain relief medications that can be systemic, regional, or local. Systemic medications affect the entire body, and a small part or area of the body is affected by local medications. If we talk about regional medication they particularly affect a particular region of the body like the region below the waist.