IBD IBD Pharmacotherapy

Question 1

What is the mechanism of action of mesalamine (5-ASA) in treating ulcerative colitis?

Accepted Answer

Local anti-inflammatory effect via inhibition of arachidonic acid metabolites and NF-κB in colonic mucosa

Answer

Mesalamine exerts topical anti-inflammatory effects in the colonic mucosa by inhibiting NF-κB, COX pathways, and arachidonic acid metabolites independently of systemic absorption.

Question 2

Which anti-TNF biologic is available as both IV infusion and subcutaneous formulation for IBD treatment?

Accepted Answer

Infliximab

Answer

Infliximab (Remicade) is primarily administered IV, but biosimilars and newer formulations now allow subcutaneous administration (infliximab SC).

Question 3

Thiopurine medications (azathioprine, 6-mercaptopurine) work primarily by which mechanism in IBD?

Accepted Answer

Inhibiting de novo purine synthesis, leading to T and B lymphocyte suppression

Answer

Thiopurines are converted to 6-thioguanine nucleotides that inhibit de novo purine synthesis and T-lymphocyte proliferation, causing immunosuppression.

Question 4

Before initiating thiopurine therapy, testing for which enzyme deficiency is recommended to prevent severe toxicity?

Accepted Answer

Thiopurine methyltransferase (TPMT) or NUDT15

Answer

TPMT and NUDT15 enzyme deficiencies impair thiopurine metabolism, leading to accumulation of toxic metabolites causing severe myelosuppression.

Question 5

Vedolizumab (Entyvio) is considered 'gut-selective' because it specifically blocks which interaction?

Accepted Answer

α4β7 integrin on lymphocytes from binding MAdCAM-1 on gut endothelium

Answer

By blocking α4β7/MAdCAM-1 interaction, vedolizumab selectively prevents gut-homing lymphocytes from entering intestinal tissue without systemic immunosuppression.

IBD - Inflammatory Bowel Disease Practice Test

IBD - Inflammatory Bowel Disease Practice Test

IBD IBD Pharmacotherapy