Non-steroidal Anti-Inflammatory Drugs (NSAIDs) Lecture Notes

Comprehensive vocabulary flashcards covering the classification, mechanism of action, pharmacological effects, and toxicity of NSAIDs and paracetamol based on the lecture notes.

Anti-inflammatory drug

A drug or substance that reduces inflammation by blocking the release of inflammatory mediators.

Inflammation

A normal response to tissue damage or infection associated with pain, fever, swelling, redness, and loss of function.

Analgesic effect

The property of drugs that reduce pain, also known as pain-killers.

Antipyretic effect

The property of drugs that decreases or relieves fever.

COX-1 (Cyclo-oxygenase 1)

An enzyme expressed constitutively in most cells (platelets, GIT, kidney) responsible for physiological or cytoprotective functions.

COX-2 (Cyclo-oxygenase 2)

An enzyme inducible by inflammation and cancer that is associated with pathological functions such as pain, fever, and inflammation.

COX-3 (Cyclo-oxygenase 3)

An enzyme found in the CNS that is inhibited by paracetamol; it is involved in pain and fever but not inflammation.

Aspirin (Acetyl Salicylic Acid)

The prototype of NSAIDs and an irreversible inhibitor of both COX-1 and COX-2.

Thromboxane A2 (TXA2)

A mediator synthesized by platelets that induces platelet aggregation and vasoconstriction; its synthesis is inhibited by low-dose aspirin ($75\text{--}100\,mg/day$).

Prostacyclin (PGI2)

A potent vasodilator produced by endothelial cells that prevents platelet aggregation.

Reye’s syndrome

A condition occurring in some children with viral infections treated with aspirin, characterized by encephalopathy and hepatotoxicity.

Uricosuric effect

An effect seen with large doses of aspirin ($>5\,g$) where uric acid excretion is increased and reabsorption is decreased.

Respiratory alkalosis

An acid-base disturbance caused by high doses of aspirin ($Low toxic dose$) that stimulate the respiratory center, leading to hyperventilation and excessive $CO_2$ wash out.

Salicylism

Chronic aspirin toxicity resulting from large doses over a long period, characterized by headache, mental confusion, vertigo, and tinnitus.

Misoprostol

A $PGE_1$ analog used to reduce the risk of gastric ulcer and treat gastric damage induced by NSAIDs.

Zileuton

An LOX inhibitor useful in the treatment of aspirin-induced bronchial asthma.

Diclofenac

A potent acetic acid derivative that accumulates in synovial fluid, making its therapeutic effect duration longer than its plasma half-life of $1\text{--}2\,hr$.

Indomethacin

A powerful non-selective COX inhibitor used for acute gout and to close patent ductus arteriosus in neonates, but avoided as a routine analgesic due to neurotoxicity.

Ibuprofen

A propionic acid derivative with analgesic, antipyretic, and anti-inflammatory actions that is safe for use in children as an alternative to paracetamol.

Naproxen

A propionic acid derivative with a half-life of $14\,hrs$ that is effective in the treatment of acute gout attacks.

Piroxicam

An oxicam NSAID with a particularly long half-life of $50\,hr$ due to enterohepatic circulation, allowing for single daily dosing.

Celecoxib

A selective COX-2 inhibitor that treats rheumatoid arthritis and osteoarthritis with fewer gastrointestinal side effects and no effect on platelet aggregation.

Paracetamol (Acetaminophen)

A para-aminophenol derivative that inhibits central but not peripheral COX, meaning it has no significant anti-inflammatory action.

NAPQI (NABQ)

N-acetyl-p-benzoiminoquinone; a toxic metabolite of paracetamol produced by Cytochrome $P450$ that causes hepatotoxicity if glutathione is depleted.

N-acetylcysteine

The antidote for paracetamol toxicity that acts as a glutathione substitute and supplies sulfhydryl ($SH$) groups to detoxify the toxic metabolite.

Salicylic acid

A salicylate used topically as a keratolytic agent to destruct superficial layers of skin for treating calluses, corns, and warts.

Methyl salicylate

Also known as wintergreen oil; used as a counterirritant applied locally to produce superficial skin irritation and hyperemia to mask deep-seated pain.