18 Questions
What is the main mechanism of action of acetylsalicylic acid?
Irreversible acetylation of COX-1 isoenzyme
What happens to acetylsalicylic acid in aqueous media?
Decomposes rapidly
Which condition is NOT an indication for the use of acetylsalicylic acid?
Allergic rhinitis
What is the effect of ASA converting to salicylic acid inside the body?
Anti-inflammatory effect
How does acetylsalicylic acid affect the body's response to interleukin 1?
Alters the response
Which of the following is NOT a therapeutic benefit of acetylsalicylic acid?
Antihistamine
What is the reason behind the decreased gastrointestinal (GI) distress associated with Salsalate compared to Aspirin?
Salsalate is relatively insoluble in the stomach, so it is not absorbed until it reaches the intestine.
Which of the following is a contraindication when using Warfarin along with Aspirin?
High protein binding of Aspirin leading to displacement of Warfarin
What therapeutic benefit does Diflunisal offer that makes it a preferred choice in certain conditions despite causing gastrointestinal distress?
Diflunisal provides a longer duration of action than Aspirin.
Why is Choline Salicylate considered extremely soluble?
Its high solubility allows for easier absorption in the body.
Which of the following best describes the chemical property of Sodium Salicylate that makes it advantageous for patients with Aspirin allergy?
Sodium Salicylate has a lower tendency to cause gastrointestinal (GI) irritation.
What distinguishes Salicylamide from Aspirin, making it a suitable alternative for patients sensitive to Aspirin?
Salicylamide gets converted into a different compound that is less irritating to the stomach.
Which statement about NSAIDs is correct?
NSAIDs possess a free carboxyl group that binds to the active site of cyclooxygenases.
Which of the following is a ketone prodrug that is metabolized to an active NSAID?
Ketorolac
Which of the following is the primary undesirable side effect of NSAIDs associated with the inhibition of thromboxane and prostacyclin?
Gastrointestinal bleeding
Who first introduced the therapeutic benefits of salicylates (aspirin) in 1763?
Reverend Edward Stone
What is the IUPAC name for aspirin?
2-acetoxybenzoic acid
Which of the following statements about the chemical properties of aspirin is correct?
It has a melting point of around $134-140^\circ\mathrm{C}$ and a boiling point of $140-284^\circ\mathrm{C}$.
Study Notes
Acetylsalicylic Acid (Aspirin)
- Unstable in aqueous media and decomposes rapidly in solutions of ammonium acetate or of the acetates, carbonates, citrates or hydroxides of the alkali metals
- Mechanism of action: decreases peripheral synthesis of PG by blocking the conversion of arachidonic acid to PG via the inhibition of the COX isoenzymes
- Inside the body, ASA is converted to salicylic acid which is responsible for its anti-inflammatory effect
Anti-inflammatory and Antipyretic Effects
- Inhibition of COX reducing the central synthesis of PGE2 in the hypothalamic area of the brain that regulates body temperature
- Increase heat elimination of the body in febrile patients via the mobilization of water and consequent dilution of the blood
- Perspiration causing cutaneous dilation alter response of the body to interleukin 1 (endogenous pyrogen)
Antiplatelet Action
- Irreversible acetylation of Ser-530 of the COX-1 isoenzyme
Dosage
- Adults:
- Oral: 300-1000 mg every 4 h; max 4 g a day for pain and fever
- Oral: 1 g 6 times a day; max 8 g a day for acute polyarthritis rheumatica
- Oral: 0.5-1 g 6 times a day; max 8 g a day for rheumatoid arthritis
- Compounds with controlled release: 1 g 2-3 times a day, if necessary 6 times a day
- Intramuscular or intravenous (lysine acetylsalicylate): 500 mg, 1-4 times a day
Contraindications
- Antacids: decreases ASA absorption
- Warfarin: due to high CHON binding of ASA; displacement of warfarin bleeding
Salsalate (Salicyl Salicylic Acid)
- Ester produced by the combination of 2 salicylic acid molecules
- Less GI distress due to being relatively insoluble in the stomach
- Converted to 2 molecules of salicylic acid
Diflunisal (DOLOBID)
- Not metabolized to salicylic acid due to high CHON binding
- Causes GI distress
- Mainly used in the treatment of OA, RA and postoperative pain due to longer duration of action
- CI in patient with kidney failure leads to nephrotoxicity
Sodium Salicylate
- ASA + NAHCO3 (EQUAL MOLE RATIO WITH SALT)
- DISADVANTAGE: DECREASE GI ABSORPTION, INCREASED EXCRETION
- ADVANTAGE: LESS GI DISTRESS
- MAINLY GIVEN TO PATIENT WITH ASA ALLERGY
Other Salts of Salicylic Acid
- Mg Salicylate (MOBIDIN, MAGAN)
- Na thiosalicylate (REXOLATE)
- Choline salicylate (ARTHROPAN)
Salicylamide
- Benzamide derivative of ASA
- For patients with ASA sensitivity
- Excreted exclusively as either gluconamide or sulphate
Explore a post lab discussion on the synthesis of aspirin, focusing on NSAIDs (Nonsteroidal Anti-Inflammatory Drugs) and their properties. Learn about the chemical structure and interactions of NSAIDs with active sites, including the role of ketone prodrugs and carboxylic acids.
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