Mechanisms of Action

Question 1

cimetidine (Tagamet)

Answer 1

H2 receptor antagonist; high potential for drug interactions, so mostly replaced by ranitidine and famotidine; used to treat certain allergic reactions

Question 2

sucralfate

Answer 2

Binds directly to the surface of an ulcer (“ulcer band-aid”). The acid dissociates sucralfate into aluminum hydroxide (an antacid) and sulfate anions, stimulating secretion of mucus and bicarbonate and creating a protective barrier over the ulcers/erosions

Question 3

diphenoxylate with atropine

Answer 3

acts on smooth muscle of the intestinal tract, inhibiting motility and excessive GI propulsion; contraindicated with pseudomembranous colitis or toxigenic bacteria (the atropine is added to discourage use as a recreational opiate drug)

Question 4

loperamide (Imodium A-D)

Answer 4

inhibits peristalsis in the intestinal wall and intestinal secretion; only opiate OTC available

Question 5

psyllium (Metamucil)

Answer 5

bulk-forming laxative; from the dried seed of Plantago psyllium plant; contraindicated in patients with abdominal pain and/or n/v

Question 6

ducosate salts (Ca++ and Na+) (Colace)

Answer 6

stool-softening emollient laxative; facilitates the passage of water and lipids into the fecal mass; lowers surface tension of GI fluids

Question 7

glycerin

Answer 7

mild hyperosmotic laxative; increases osmotic pressure in the intestine, drawing fluid into the colon; increases fecal water content resulting in distention, increased peristalsis, and evacuation; often used for children

Question 8

meclizine (Antivert)

Answer 8

antihistamine used to treat dizziness, vertigo, and nausea; binds primarily to H1 receptors, but also has anticholinergic effects (antisecretory and antispasmodic), preventing cholinergic stimulation of vestibular and reticular systems (cause of nausea)

Question 9

metoclopramide (Reglan)

Answer 9

prokinetic drug: blocks dopamine receptors in the chemoreceptor triggering zone (CTZ), desensitizing the CTZ to impulses from the GI tract; enhances gastric emptying

Question 10

ondansetron (Zofran)

Answer 10

serotonin blocker; blocks serotonin receptors in the GI tract, CTZ, and vomiting center; used in treatment of n/v associated with chemotherapy and pregnancy (hyperemesis gravidarum)

Question 11

Vitamin A (retinol) (Aquasol A)

Answer 11

essential for normal cell growth and differentiation; involved in the growth and development of bones and teeth and in other processes such as reproduction, maintenance/integrity of mucosal and epithelial surfaces, and cholesterol/steroid synthesis

Question 12

vitamin d3, calcifediol (Calderol)

Answer 12

used for management of hypocalcemia in patients undergoing hemodialysis and for signs of hyperparathyroidism

Question 13

vitamin d3, calcitriol (Rocaltrol)

Answer 13

used for management of hypocalcemia in patients undergoing hemodialysis; in treatment of hypoparathyroidism, pseudohypoparathyroidism, vitamin D-dependent rickets, and hypocalcemia in premature infants

Question 14

vitamin E (Aquasol E)

Answer 14

powerful biologic antioxidant; deficiency may result in irritability, edema, thrombosis, and hemolytic anemia

Question 15

vitamin K, phytonadione (AquaMEPHYTON)

Answer 15

facilitates biosynthesis of clotting factors; deficiency results in hypoprothrombinemia; deficiency is rare because intestinal flora are normally able to synthesize sufficient amounts

Question 16

vitamin B1, thiamine

Answer 16

required for the citric acid cycle (Krebs), a major part of carbohydrate metabolism; also plays a role in the integrity of the peripheral nervous sytem, CV system, and GI tract

Question 17

vitamin b2, riboflavin

Answer 17

converted into two enzymes that are essential for tissue respiration; plays important part in carbohydrate catabolism; needed for activation of b6; needed for conversion of tryptophan into b3 and maintenance of erythrocyte integrity

Question 18

vitamin b3, niacin

Answer 18

required for carbohydrate, protein, purine, and lipid metabolism and tissue respiration; also used for antilipemic effect

Question 19

vitamin b6, pyridoxine

Answer 19

necessary for protein, carbohydrate, and lipid metabolism and conversion of tryptophan to niacin; essential in synthesis of gamma-aminobutyric acid (GABA) and heme, therefore necessary for integrity of peripheral nerves, skin, and mucous membranes

Question 20

vitamin b12, cyanocobalamin

Answer 20

required for nucleoprotein and myelin synthesis, cell reproduction, normal growth, and maintenance of normal erythropoiesis

Question 21

vitamin C, ascorbic acid

Answer 21

required for collagen synthesis, maintenance of connective tissue; tissue repair; maintenance of bone, teeth, and capillaries; folic acid metabolism; erythropoiesus; synthesis of lipids, proteins, and steroids; enhances absorption of iron

Question 22

calcium

Answer 22

involved in proper development and maintenance of teeth and skeletal bones; catalyst in many of the coagulation pathways in the blood; cofactor in clotting reactions and conversion of prothrombin to thrombin and fibrinogen to fibrin; essential for the maintenance & function of nervous, muscular, & skeletal systems; transmission of nerve impulses and muscle contractions; release and storage of neurotransmitters and hormones, uptake and binding of amino acids, and in intestinal absorption of cyanocobalamin

Question 23

magnesium

Answer 23

known cofactor for many enzyme systems; required for muscle contraction and nerve function; produces an anticonvulsant effect by inhibiting neuromuscular transmission

Question 24

phosphorus

Answer 24

precursor for the synthesis of essential body chemicals; important building block for body structures; structural unit for synthesis of nucleic acids, ADP, and ATP; necessary for the development of skeletal system and teeth (bones contain 85% of phosphorus in body)

Question 25

ketoconazole

Answer 25

antifungal- DO NOT take with H2 antagonists

Question 26

omeprazole (Prilosec)

Answer 26

proton pump inhibitor; binds to the hydrogen-potassium-ATPase pump (proton pump), preventing movement of hydrogen ions out of parietal cells into the stomach. Prevents more than 90% of acid secretion over 24 hours.

Question 27

antacids, general

Answer 27

neutralize gastric acidity; stimulate secretions of mucus, prostaglandins, and bicarbonate

Question 28

antacids, Mg++ and Ca++ based

Answer 28

avoided in patients with real disease, due to possible toxicity

Question 29

antacids, Mg++

Answer 29

commonly have a laxative effect and can rarely be tolerated alone

Question 30

antacids, Al+++

Answer 30

Can lead to constipation

Question 31

antacids, Al+++ and Na+ based

Answer 31

recommended for patients with renal compromise because they are more easily excreted

Question 32

bismuth subsalicylate (Pepto Bismol)

Answer 32

adsorpent drug; coats the walls of the GI tract, attracting the toxins/bacteria to its surface for elimination from the body; form of aspirin

Question 33

magnesium hydroxide (Milk of Magnesia)

Answer 33

hyperosmotic laxative; increases osmotic pressure in the small intestine by inhibiting water absorption; very potent

Question 34

methylcellulose (Citrucel)

Answer 34

bulk forming laxative; attracts water into the intestine and absorbs excess water into the stool, stimulating the intestines and increasing peristalsis; contraindicated in GI obstruction and hepatitis

Question 35

belladonna alkaloid (Donnatal)

Answer 35

anticholinergic used for antidiarrheal; slows peristalsis, reduces gastric secretions, and has a drying effect; used in combination with opioids and adsorbents

Question 36

scopolamine

Answer 36

anticholinergic used for antiemesis; binds to ACh receptors in the vestibular nuclei (deep in the brain); nausea-inducing signals are then blocked from being transmitted to the CTZ; also blocks signals between the reticular formation and the vomiting center

Question 37

dronabinol (Marinol)

Answer 37

only commercially available THC; has inhibitory effects on the thalamus, reticular formation, and cerebral cortex; also stimulates appetite in AIDS/ cancer patients

Question 38

feverfew

Answer 38

member of the marigold family; antiinflammatory properties; treatment of migraines, menstrual cramps, inflammation, and fever; adverse effects: n/v, constipation, diarrhea, muscle stiffness/joint pain, altered taste

Question 39

echinacea

Answer 39

immunostimulant effects; promotion of healing wounds; reduces cold symptoms/recovery time; antisepsis; treatment of viral infections and flu-like respiratory infections, and chronic ulcerations

Question 40

lactobacillus (Bacid)

Answer 40

probiotic; acid-producing bacteria; used for treatment in uncomplicated diarrhea, particularly in that caused by antibiotic therapy

Question 41

garlic (allium sativum)

Answer 41

active ingredient: allicin; antispasmodic, antiseptic, antibacterial, and antiviral; antihypertensive; antiplatelet; lipid reducer

Question 42

treatment options for Helicobacter pylori

Answer 42

1st line: 10-14 day course of proton pump inhibitor and antibiotics clarithyromycin and either amoxicillin or metronidazole OR combo of proton pump inhibitor with bismuth subsalicylate and antibiotics tetracycline and metronidazole

Question 43

H2 receptor antagonists

Answer 43

blocks H2 receptor of parietal cells, decreasing the response to histamine and the stimulation of ACh & gastrin (blocks up to 90% of vagal- and gastrin-stimulated acid secretion