NR 565 Exam Final Study Guide (Week 7-8)

NR 565 Exam Final Study Guide (37 Pages)

•   Antacids: weak bases that react with hydrochloric acid to form salt & water.
  o UsedinthetreatmentofHyperacidity,GERD,PUD,hyperphosphatemia,andcalciumdeficiency 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 Increaseloweresophagealsphinctertone
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).

   •   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

   •   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

o Aluminum 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

Aluminum is not easily removed by dialysis b/c it is bound to albumin & transferrin = do not cross dialysis membrane

3. Magnesium based: Milk of mag, Maalox, Mylanta

The malfunctioning kidney cannot excrete magnesium= hypermagnesemia may result

•   Can be used to treat magnesium deficiencies from malnutrition, alcoholism, or mag-depleting drugs

•   Contraindicated in patients with renal failure & used with caution in pts with renal insufficiency

•   Not absorbable with routine use

•   Excreted in the urine

•   Contraindicated in patients with renal failure, use with caution for patients with any degree of renal insufficiency

o Malfunctioning kidney is unable to excrete magnesium and hypermagnesemia may result  Can cause diarrhea- increase fiber intake (Alkalosis may occur in renal impairment)