NR 565 Exam Final Study Guide
➢Antacids: weak bases that react with hydrochloric acid to form salt & water.
oUsed in the treatment of Hyperacidity, GERD, PUD, hyperphosphatemia, and calcium deficiency
oContain combinations of
▪metallic cation (aluminum, calcium, magnesium, and sodium)
▪and basic anion (hydroxide, bicarbonate, carbonate, citrate, and trisilicate)
➢Pharmacodynamics, Pharmacokinetics, Pharmacotherapeutics
oNeutralize Gastric Acidity (causes ^pH of the stomach and duodenal bulb)
oInhibit proteolytic activity of pepsin
oIncrease lower esophageal sphincter tone
oAcid-neutralizing capacity ANC varies between products expressed in mEqs
oIf ingested in a fasting state, antacids reduce acidity for approximately 20 to 40 minutes
oIf taken 1 hr after a meal, acidity is reduced for 2 to 3 hrs
oA second dose taken after a meal maintains reduced acidity for more than 4 hrs after the meal
oThe action of antacids occurs locally in the GI tract with minimal absorption, minimal metabolism
oALL antacids are contraindicated in the presence of severe abdominal pain of unknown cause, especially
if accompanied by fever
-HIGH SODIUM content: pts w/ HTN, CHF, marked renal failure, or on low-sodium diets need to use low sodium
preparation
-Concurrent administration with enteric-coated drugs, destroys the coating= alters absorption, ^ the risk for
adverse effects
-Administrations should be separated by at least 2 hours to decrease drug/drug interactions
1. Calcium based antacids: TUMS, Caltrate, Calcarb
•Prescribed to treat calcium deficient states, i.e. chronic renal failure, post-menopause, and osteoporosis
•Used to bind phosphates in CRF
•Require Vitamin D for absorption from the GI tract
•Excreted mainly in feces, 20% in urine
•ADR: Contraindicated in the presence of hypercalcemia and renal calculi
•Can cause constipation- increase bulk, fluids and mobility, stool softener
•Administered 30min- 1hr on empty stomach or 3hr after meals
•Should not be administered with food containing large amounts of oxalic acid (spinach, rhubarb),
or phytic acid (bran, cereals), they decrease the absorption of calcium
•Taking w/ foods containing phosphorus (milk, dairy) can lead to milk-alkali syndrome (N/V,
confusion, headache).
•Taking with acidic fruit juice improve absorption
2. Aluminum based: AlternaGEL, Amphojel, Mylanta
•Inhibit smooth muscle contraction and slow gastric emptying
•Used to bind phosphates in CRF
Aluminum is not easily
removed by dialysis b/c
it is bound to albumin
& transferrin = do not
cross dialysis
membrane
•Not absorbable with routine use
•Aluminum concentrated in the CNS
•Bind with phosphate and excreted in feces
•Prolonged use in patients with renal failure may result in dialysis osteomalacia
oAluminum deposits in bone and osteomalacia occurs
•Elevated aluminum tissue levels contribute to the development of dialysis encephalopathy
•Used to treat hyperphosphatemia in pts w/ renal failure & phosphate renal stone prevention
•Can cause constipation- increase bulk, fluids and mobility, stool softener
3. Magnesium based: Milk of mag, Maalox, Mylanta
