GI Disorders Medications

Question 1

Glucocorticoids

Answer 1

Used in various dosage forms for mild to severe IBD

Induce remission, but other drugs are used to maintain remission

Question 2

Dicyclcomine [Bentyl]

Answer 2

• Acts as an anti-spasmodic
• ⊗ Muscarinic receptors on enteric plexus and smooth muscle
• Higher doses ⇒ anti-cholinergic side effects such as dry mouth, blurred vision etc.
• Not frequently used

Question 3

Sulfasalazine & Mesalamine

Answer 3

Sulfasalazine and its metabolite mesalamine

• Used to induce and maintain remission
• Active component is 5-aminosalicylic acid
  
  • ⊗ Prostaglandin synthesis
  • ⊗ Migration of neutrophils
  • Acts as a free radical scavenger
• Sulfasalazine: higher incidence of AEs vs mesalamine d/t sulfa component
• Mesalamine can be administered as a rectal suppository

Question 4

Immunosuppressive Drugs

Answer 4

Azathioprine and 6-mercaptopurine for moderate IBD

Causes ↓ glucocorticoids

Question 5

Methotrexate

Answer 5

Efficacious for moderate Crohn’s but its efficacy in ulcerative colitis is less clear.

Question 6

Metronidazole and Tinidazole

Answer 6

• Members of the nitroimidazole family
• Nitro group reduced in anaerobic bacteria and sensitive protozoans
• Works against gut anaerobes and bactericidal vs obligate anaerobes
• Reactive products responsible for antimicrobial activity
• Active against the following microbes that cause diarrhea: Clostridium difficile, Giardia lamblia, and Entamoeba histolytica
• Also active against gram positive and negative anaerobes including Bacterioides, Fusobacterium, and the protozoan Trichomonas
• Moderately active against Heliobacter pylori
• Major AEs: nausea, headache, anorexia, and metallic taste
  
  • Tinidazole has fewer AEs
• No alcohol for 24 hrs after metronidazole and 72 hrs after tinidazole d/t disulfiram reaction
• ⊗ Warfarin metabolism thereby potentiating its effect (cytochrome p450)
• Metronidazole is class B for pregnancy, tinidazole is class C

Question 7

Trimethoprim/Sulfamethoxazole

and

Fluoroquinolones

Answer 7

May be used in severe cases of Salmonella, Shigella, E. Coli and Campylobacter or in pts w/ comorbidities

Question 8

Erythromycin

Answer 8

Used in severe cases of Campylobacter or in pts w/ comorbidities

Question 9

Iodoquinol

Answer 9

• Commonly used w/ metronidazole to tx amebic infections
• Most of the drug remains in the lumen
• It may cause diarrhea and rash