5.9 Pain Medicines Reduce Or Numb Pain in Human Body

Analgesics are also called painkillers. These medicines reduce or numb pain in the body through various mechanisms that affect the nervous system. There are different types of pain medications and each works in unique ways to interfere with pain signals.

Definition

Analgesics: Analgesics are also called painkillers. These medicines reduce or numb pain in the body through various mechanisms that affect the nervous system.

Main Idea

• Non-Steroid Anti-inflammatory Drugs (NSAIDs)
• Acetaminophen (Paracetamol)
• Opioids
• Local Anesthetics
• Antidepressants and anticonvulsants
• Corticosteroids
• Other medicines

Core Concept

• **Analgesics** = painkillers
• NSAIDs = inhibit cyclooxygenase (COX); reduce prostaglandins
• Acetaminophen = acts on brain's pain center; inhibits COX in brain
• Opioids = bind to opioid receptors; block pain signals
• Local anesthetics = block sodium channels
• Antidepressants and anticonvulsants = modulate neurotransmitters
• Corticosteroids = reduce swelling and inflammation

Detailed Explanation

Main Categories of Pain Medications

a. Non-Steroid Anti-inflammatory Drugs (NSAIDs)

• These medicines work by inhibiting the activity of an enzyme called cyclooxygenase (COX).
• COX plays a key role in the production of prostaglandins.
• Prostaglandins are chemicals released at the site of injury or inflammation that cause pain, swelling and fever.
• By reducing the production of prostaglandins, NSAIDs help to reduce inflammation and numb pain.

b. Acetaminophen (Paracetamol)

• It is believed that it works by acting on brain's pain center.
• It likely inhibits COX enzymes in the brain.
• This reduces the perception of pain without the anti-inflammatory effect.

c. Opioids

• These are also called narcotics.
• Opioids bind to opioid receptors in the brain, spinal cord and other parts of the nervous system.
• These receptors are involved in the transmission and perception of pain.
• When opioids bind to these receptors, they block pain signals from being transmitted to the brain.
• They also increase the brain's threshold for pain, essentially dulling or eliminating the sensation of pain.

d. Local Anesthetics

• These work by blocking sodium channels in nerve cells.
• Sodium channels are essential for the transmission of electric signals along nerves.
• By blocking these channels, local anesthetics prevent pain signals from travelling from the site of injury to the brain.
• These are commonly used for procedures where localized numbing is required, such as dental work or minor surgeries.

e. Antidepressants and Anticonvulsants

• These medicines are used to treat chronic pain, particularly nerve pain.
• They work by modulating the neurotransmitters involved in pain perception, such as serotonin and norepinephrine.

f. Corticosteroids

• They reduce swelling and inflammation, which in turn reduces pain.
• They work by inhibiting the production of inflammatory chemicals and suppressing the immune response.

g. Other Medicines

• These numb localized area.
• Some are used to relax muscles.

Certain Pain Medications are Addictive

• Physicians typically prescribe opioids to manage moderate to severe pain.
• However, opioids can become addictive because they not only dull pain, but also produce a sense of euphoria (intense happiness).
• This, combined with tolerance build (needing to increase doses to produce the same effect), can lead to opioid use disorder.
• Opioids also cause neurons that produce dopamine, the neurotransmitter which plays a role in how we feel pleasure, or strong reactions to something. This creates feelings of euphoria.
• Physicians reduce the length and strength of opioids to try to prevent addiction.

Summary Table of Pain Medications

Intermediate Level

Categories of Pain Medications

Detailed Mechanism of Each Category

Addictive Potential

Formula / Mathematical Form

Not applicable to this topic.

Solved Example

Not applicable to this topic (descriptive topic).

Important Points

• 1. Analgesics are painkillers.
• 2. They reduce or numb pain.
• 3. They affect the nervous system.
• 4. NSAIDs inhibit COX enzymes.
• 5. NSAIDs reduce prostaglandins.
• 6. Acetaminophen acts on brain's pain center.
• 7. Opioids bind to opioid receptors.
• 8. Opioids block pain signals.
• 9. Opioids increase pain threshold.
• 10. Local anesthetics block sodium channels.
• 11. Local anesthetics prevent pain signal transmission.
• 12. Antidepressants and anticonvulsants modulate neurotransmitters.
• 13. Corticosteroids reduce swelling and inflammation.
• 14. Other medicines numb localized area and relax muscles.
• 15. Opioids can be addictive.
• 16. Opioids produce euphoria.
• 17. Opioids cause dopamine release.
• 18. Physicians reduce length and strength of opioids to prevent addiction.
• 19. Each pain medication works in a unique way.
• 20. Pain medications are essential for managing pain.

Remember

• - **Analgesics** = painkillers
• - NSAIDs = inhibit COX; reduce prostaglandins
• - Acetaminophen = acts on brain's pain center
• - Opioids = bind to opioid receptors; block pain signals
• - Local anesthetics = block sodium channels
• - Antidepressants and anticonvulsants = modulate neurotransmitters
• - Corticosteroids = reduce swelling and inflammation
• - **Opioids** = can be addictive
• - Opioids = produce euphoria
• - Opioids = cause dopamine release

Common Mistakes

• 1. Confusing NSAIDs and acetaminophen — NSAIDs reduce inflammation; acetaminophen does not.
• 2. Thinking all pain medications are addictive — Only opioids have high addictive potential.
• 3. Mixing up the mechanisms — NSAIDs inhibit COX; opioids bind to receptors; local anesthetics block sodium channels.
• 4. Forgetting the role of prostaglandins — They cause pain, swelling, and fever.
• 5. Thinking acetaminophen reduces inflammation — It does not.
• 6. Confusing opioids and narcotics — Opioids are also called narcotics.
• 7. Forgetting the role of sodium channels — Local anesthetics block them.
• 8. Believing corticosteroids are painkillers — They reduce swelling and inflammation, which reduces pain.
• 9. Thinking antidepressants are only for depression — They are also used for chronic pain.
• 10. Underestimating opioid addiction — Opioids can lead to opioid use disorder.

Quick Revision

Analgesics are also called painkillers. These medicines reduce or numb pain in the body through various mechanisms that affect the nervous system. There are different types of pain medications and each works in a unique way to interfere with pain signals. Non-Steroid Anti-inflammatory Drugs (NSAIDs) work by inhibiting the activity of an enzyme called cyclooxygenase (COX), which plays a key role in the production of prostaglandins. Acetaminophen (Paracetamol) is believed to work by acting on brain's pain center. Opioids are also called narcotics. Opioids bind to opioid receptors in the brain, spinal cord and other parts of the nervous system. Local Anesthetics work by blocking sodium channels in nerve cells. Antidepressants and anticonvulsants are used to treat chronic pain, particularly nerve pain. Corticosteroids reduce swelling and inflammation, which in turn reduces pain. Certain pain medications are addictive. Physicians typically prescribe opioids to manage moderate to severe pain. However, opioids can become addictive because they not only dull pain, but also produce a sense of euphoria. This, combined with tolerance build, can lead to opioid use disorder.

60-Second Revision

• Analgesics = painkillers
• NSAIDs = inhibit COX; reduce prostaglandins
• Acetaminophen = acts on brain's pain center
• Opioids = bind to opioid receptors; block pain signals
• Local anesthetics = block sodium channels
• Antidepressants and anticonvulsants = modulate neurotransmitters
• Corticosteroids = reduce swelling and inflammation
• Opioids = can be addictive
• Opioids = produce euphoria
• Opioids = cause dopamine release
• Warning: Opioids can be addictive due to euphoria and tolerance

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• 5. Nervous System of Man

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• 5.10 DISORDERS OF THE NERVOUS SYSTEM

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