Aminosalicylates

Question 1

Sulfasalazine structure

Answer 1

Sulfapyridine (sulfonamide) + 5-ASA (mesalamine)

Sulfapyridine: inactive but associated with side effects

5-ASA: active locally

Question 2

Sulfasalazine MOA

Answer 2

Cleaved by colonic bacteria to release sulfapyridine, which absorbed and renally excreted and 5-ASA remains in the lumen and excreted in stool

Anti-inflammatory effects and free radical scavenging

Question 3

Sulfasalazine side effects

Answer 3

N/V

HA

Rash

Anorexia

Less common: anemia, hepatotoxicity, thrombocytopenia, pneumonitis, lymphoma, nephritis

CAUTION SULFA ALLERGY

Question 4

Sulfasalazine monitoring

Answer 4

CBC and LFT baseline, every other week for 3 months, monthly for 3 months

BUN/SCr periodically

Question 5

Sulfasalazine drug interactions

Answer 5

anticoagulants, antiplatelets, NSAIDS–> increase bleeding risk

Question 6

Mesalamine PK

Answer 6

Rapidly and completely absorbed in small intestine but not colon

Question 7

Mesalamine formulations

Answer 7

Topical (enema): left-sided disease

Suppository: proctitis

Oral: delayed/controlled release

CAN COMBINE FORMULATION ROUTES

Question 8

Mesalamine side effects

Answer 8

Common: N/V, HA, Diarrhea (olsalazine)

Less common: diarrhea/constipation, rash, anemia/hepatotoxicity, UC exacerbation

Question 9

Mesalamine drug interactions

Answer 9

anticoagulants, antiplatelets, NSAIDS–> increase bleeding risk

PPI, H2RA, Antacids–> may influence release of drug based on pH