NR 565 Final Exam Study Guide_2021 - Johns Hopkins University (Answers and Question 96.7%)
Antacids: weak bases that react with hydrochloric acid
... [Show More] to form salt & water.
o Used in the treatment of Hyperacidity, GERD, PUD, hyperphosphatemia, and calcium deficiency
o Contain combinations of
metallic cation (aluminum, calcium, magnesium, and sodium)
and basic anion (hydroxide, bicarbonate, carbonate, citrate, and trisilicate)
Pharmacodynamics, Pharmacokinetics, Pharmacotherapeutics
o Neutralize Gastric Acidity (causes ^pH of the stomach and duodenal bulb)
o Inhibit proteolytic activity of pepsin
o Increase lower esophageal sphincter tone
o Acid-neutralizing capacity ANC varies between products expressed in mEqs
o If ingested in a fasting state, antacids reduce acidity for approximately 20 to 40 minutes
o If taken 1 hr after a meal, acidity is reduced for 2 to 3 hrs
o A second dose taken after a meal maintains reduced acidity for more than 4 hrs after the meal
o The action of antacids occurs locally in the GI tract with minimal absorption, minimal metabolism
o ALL 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). [Show Less]