Upper GI Drugs

Question 1

H2 Receptor Blockers

Answer 1

“tidine”

Cimetidine - specific side effects

Ranitidine - longer lasting than Cimetidine

Famotidine - most potent. Often given before surgery to reduce risk of aspiration pneumonitis

Nizatidine - less hepatic metabolism. More orally available (100%)

Question 2

PPI’s

Answer 2

“prazole” - inhibit all 3 sources of acid stimulators: Vagus, Gastrin, and Histamine

Omeprazole - mixture of R&S enantiomers.
Lanosoprazole
Esomeprazole - purified S enantiomer
Pantoprazole
Rabeprazole - most efficacious

One K+ out for each H+ retained

Question 3

Muscarinic Antagonists

Answer 3

Block M3 Receptor - Reduce meal stimulated acid secretion and increase mucosal protection

Pirenzipine
Telenzepine

Question 4

Prostaglandin Analog

Answer 4

Inhibit gastric acid, Increase bicarb secretion, Improve mucosa, Maintain tight junctions, Vasodilation to enhance mucosa flow

MISOPROSTOL - also used for therapeutic abortions in 1st and 2nd trimester. Must be take 4x per day

DO NOT GIVE TO PREGNANT WOMEN

Question 5

Mucosal Protectant

Answer 5

SUCRALAFATE - polymerizes in acidic environment forming a gel that adheres to ulcers

Must be taken 4x per day for weeks - poor compliance
Safe during pregnancy

Question 6

Bismuth Subsalicylate

Answer 6

Peptobismol!

Stimulate mucus, Coat Ulcer, Anti-inflammatory
Weak antacid

SE: Black tongue, Black stool

Question 7

Antacids

Answer 7

Must be taken at APPROPRIATE Doses: 40-80 mEq
Reduce the absorption of all H2 Blockers

Systemic: Calcium or Sodium based Bicarb
Nonsystemic: Aluminum or Mg based Bicarb

1. Al Antacids - most commonly used. May chelate drugs
2. Mg Antacids - laxative action
3. Avoid Na antacids - lots of liquid homeostasis issues
4. Ca Antacids - may increase risk of stones

Question 8

Prokinetics

Answer 8

MOTOCLOPRAMIDE - tickler
BETHANECHOL

Significant side effects, do not work as well as PPI’s

Question 9

Triple Therapy

Answer 9

PPI + Clarithromycin + Amox

Or replace Amox with Metronidazole if Penicillin allergy
Quad Therapy: Add Peptobismol

Question 10

Cimetidine Side Effects

Answer 10

Headache, Dizziness
Hepatic Dysfunction
CNS Effects - Confusion, Restlessness (elderly)
DRUG INTERACTIONS (CYP)

Increases estrogenic activity and secretion of prolactin
Anti-androgenic: Impotence, loss of libido

Question 11

Cimetidine Drug Interactions

Answer 11

Uses multiple CYP450’s

Levels increased: Warfarin, Theophylline, Phenytoin, Lidocaine, Quinidine, Propanalol, Metoprolol, Tricyclic Anti-Depressants, Benzodiazepens, Calcium Channel Blockers, Sulfonylureas, and Ethanol

Levels decreased: Itrazonazole, Ketaconazole

Question 12

Ranitidine SE

Answer 12

Acute Porphyria

Question 13

Famotidine SE

Answer 13

May cause Hypersensitivity Reaction

Question 14

H2 Blocker Precautions

Answer 14

Kidney or Liver Disease - may build up in bloodstream and increase risk of side effects

Question 15

PPI SE

Answer 15

Omeprazole (CYP) - increased levels of Warfarin, Phenytoin, Diazepam, and Cyclosporin. DECREASE AZOLES

Omeprazole - might be bad for pregnancy. Other ones are fine. Don’t do them during breastfeeding

Risk of osteoporosis - impaired absorption of Ca, Mg, and Fe
Long term - B12 Deficiency

Question 16

Misoprostol Contraindication

Answer 16

PREGNANCY - Misoprostol causes abortions

Question 17

TX for NSAID induced Ulcer

Answer 17

Stop NSAID

Treat with PPI/H2 Blocker for 8 weeks

Question 18

GERD Treatment

Answer 18

1. Lifestyle
2. PPIs
3. Coating agents - Sucralafate
4. Antacids
5. Promotility/Prokinetic Agents - help tighten LES and promote gastric emptying