NSAIDs/Non-Narcotic Analgesics/Analgesics-Antipyretics-Anti-inflammatory Drugs

The word NSAID is expanded as Non Steroidal Anti-inflammatory Drugs. The same group of drugs are also called Non-Narcotic Analgesics or Analgesic-Antipyretic-Anti-inflammatory Drugs.

The word used is – Non-steroidal – because steroids are one of the most potent anti-inflammatory drugs; and we want to emphasize that NSAIDs exert anti-inflammatory effect, but they are not steroidal in nature.

 

Why the word Non-Narcotic Analgesics –

The most potent analgesic drugs are Narcotics (Narcosis = Central nervous system depression) (Morphine-like drugs).

NSAIDs produce analgesic effect without depressing central nervous system; hence they are termed Non-Narcotic Analgesics.

Its extremely important not to have narcotic / central nervous system depressant effect for for relieving minor pains in day to day life. Thus Non-Narcotics are the most commonly used drugs for relieving pain.

SAQ/Viva

Mention the differences between Narcotic Analgesics and Non-narcotic Analgesics.

Narcotic Analgesics Non-Narcotic Analgescis
Produce CNS depression Less CNS depression
Analgesic action is mainly central Analgesic action is mainly peripheral
Opioid receptors Peripheral pain receptors
Cardiovascular system depression Minimal
Respiratory depression Minimal
Abuse liability is remarkable (Drug dependence) No abuse liability
Physical dependence No physical dependence
Mostly used for emergencies and severe pains Mostly used for day to day pain relief and mild to moderate pains
e.g. Morphine, Buprenorphine, Pethidine, Pentazocin, Fentanyl e.g. Aspirin, Paracetamol, Ibuprofen, Diclofenac,Naproxen, Mefenamic acid
Type of pain relieved
Acute Subacute, Chronic
Shooting, excruciating Dull
Severe Mild to moderate
Visceral pain Integumental; sometime also visceral
Deeper pain Superficial pain

SAQ/MCQ/Viva

Mention the non-narcotic analgesics without anti-inflammatory action.

Paracetamol (Acetaminophen) and Ketorolac have analgesic action, but they are poor (modest) at anti-inflammatory action.

This is why paracetamol is mostly used for relieving pain (analgesic action) and decreasing body temperature (anti-pyretic action), but not for inflammatory conditions.

Similarly ketorolac is mostly used to relieve the pain.


Mention pharmacological actions of Aspirin / NSAIDs / Non-narcotic analgesics.

  1. Analgesic action: This is mostly peripheral, by acting on peripheral pain receptors by decreasing their sensitivity. Because NSAIDs inhibit cyclooxygenase-2 (COX-2) and inhibit synthesis of  prostaglandins (PGs), Bradykinin (BK) TNF-alpha (Tumor necrosis factor alpha). 
  1. Antipyretic action: By 2 mechanisms. 1- Central, by acting on hypothalamus and re-setting the thermostat. 2-Peripheral, by producing cutaneous vasodilation (dilation of blood vessels in the skin) and sweating –> dissipation of heat
  2. Anti-inflammatory action: on – chemical mediators, stabilizes lysosomal memb, decrease mucopolysaccharides, decrease edema (1.2-1.5 g q 8h)
  3. Antiplatelet action: (anti-aggregatory action on platelets) (only ASPIRIN IN LOW DOSES)): Inhibits TXA2 synthesis [(Thromboxane A2)– Irreversible COX inhibition – (acetylation) – Long lasting effect – 7-10 days – (lifetime of platelets) (platelets – no nucleus – no de novo protein synthesis)]
  4. Respiration & Acid base imbalance:   Moderate doses: Resp alkalosis.   Toxic doses: accumulation of co2 , resp acidosis and metabolic acidosi
  5. Decrease renal/stomach PGs

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