DSNM Digestion Drugs Flashcards
This drug is known to promote gastric emptying by blocking the receptor for Acetylcholine on cholinergic motor neurons. It is a promotility agent.
Metoclopramide
Describe the mechanism and effect of Proton Pump Inhibitors (such as Zantac). What is the side-effect of prolonged use?
PPIs reduce acid secretion in the stomach. Zantac is a histamine-2 blocker that reduces the the effect of histamine on parietal cells thereby reducing HCl production. Prolonged use can result in G-cell hyperplasia and ECL tumors, increasing the risk of stomach cancer.
What effect would a PPI such as omeprazole have after a major meal? Why?
This will decrease the pH of gastric venous blood. This is due to the lowered secretion of H+ into the stomach lumen which couples with reduced secretion of HCO3- into venous blood.
Describe how Cholestyramine (Questran) can be used to treat high cholesterol.
Questran is a bile acid sequestrant (BAS) that binds bile acids in the intestine to take them out of the system. This INCREASES the conversion of cholesterol to bile acids and eliminates it from the body.
Why would a patient with cholesterol gallstones be given Chenodeoxycholic acid?
Chenodeoxycholic acid is a MORE POLAR bile salt that increases cholesterol’s solubility in bile. The high % of this component prevents crystallization.
What is the function of Statin drugs? How do they work?
Statin drugs reduce cholesterol by acting as competitive inhibitors to HMG CoA Reductase enzyme. This drug effectively reduces LDL levels by upregulating LDL receptors in the liver.
What effect does HMG CoA-Reductase Inhibitor have on LDL, HDL and TAGs? Describe its mechanism of action.
HMG-CoA Reductase Inhibitor highly reduces LDL, reduces triglycerides and increases HDL levels. It does this by inhibiting the conversion of HMG CoA to mevaolnate (a cholesterol precursor).
What effect do Bile Acid Sequestrants (Resins) have on LDL, HDL and TAGs? Describe its mechanism of action.
Bile acid resins (cholestyramine, colestipol and colesevelam) decrease LDL, slightly increases HDL and TAGs. These prevent intestinal reabsorption of bile acids causing the liver to use cholesterol to make more BAs.
What effect does Ezetimibe have on LDL, HDL and TAGs? Describe its mechanism of action.
Ezetimibe lowers LDL levels and increases or has no change on HDL and TAGs. It reduces the small intestinal enterocyte uptake of cholesterol by binding to NPC1L1.
What effect do Fibrates have on LDL, HDL and TAGs? Describe its mechanism of action.
Fibrates (Gemfibrozil, bezafibrate, fenofibrate) lower LDL levels, increase HDL levels and DRASTICALLY REDUCE TAGs/vLDL. This upregulates LPL to increase TAG clearance. It also activates PPAR-alpha to induce HDL synthesis.
What effect does Niacin (B3) have on LDL, HDL and TAGs? Describe its mechanism of action.
B3 (aka Nicotinic acid) lowers LDL and TAGs in the body + increases HDL levels. Niacin does this by inhibiting the mobilization of FFAs from peripheral adipose tissue to the liver.
What effect do PCSK9 inhibitors have on LDL, HDL and TAGs? Describe its mechanism of action.
PCSK9 inhibitors (alirocumab, evolocumab) DRASTICALLY reduce LDL levels, increase HDL and reduce TAGs. It works by inactivating LDL-receptor degradation; therefore, increasing the amount of LDL removed from circulation.
What drug would best be used to treat a condition with a loss of LPL/ ApoCII? Why?
Fibrates would be best to treat this disorder since they will reduce the TAGs acquired from diet after meals.
What is the mechanism of Metformin for treatment of Diabetes? What is the significance of this drug?
Metformin down-regulates gluconeogenesis genes. This drug has one of the lowest incidences of hypoglycemia when used to treat diabetic patients.
What are the side effects of 2,4-dinitrophenol (DNP)?
Increased respiration rate, oxygen consumption and body temperature (via uncoupling ETC from ox phos).
