Antacids, action

Salt of Salicylic Acid. A large number of salts of salicylic acid have been prepared and evaluated for therapeutic or other commercial use. Sodium salicylate has analgesic, antiinflammatory, and antipyretic activities. Magnesium salicylate, an analgesic and antiinflammatory agent, appears to have exceptional ability to relieve backaches. It is also used for the symptomatic relief of arthritis. Bismuth subsalicylate is taken orally in combination with other ingredients for protective, antacid action as well as antidiaiiheal and antiseptic effects. 

Many types of bismuth mineral salts (e.g., bismuth subsalicylate) are generally multipurpose intestinal medicinal agents. As an antisecretory agent, bismuth subsalicylate coats and protects irritated and inflamed intestinal lumen tissue (antiulcer actions), decreases the secretion of fluid into the intestine, absorbs or neutralizes bacterial toxins, inhibits any bacterial activity (antidiarrhea actions), and also increases alkaline secretion to counteract any acid production (antacid action). Thus, this agent controls the frequent voluminous loss of watery stools while relieving intestinal cramping and irritation. 

CAN YOU ANSWER THIS Look at the label of Mylanta shown in the photograph. Can you identify the bases responsible for the antacid action Write chemical equations shounng the reactions of these bases with stomach acid (HCl). 

Capsules or tablets should be taken with water unless the primary health care provider or pharmacist directs otherwise (eg, take with food, milk, or an antacid). Some liquids, such as coffee, tea, fruit juice, and carbonated beverages, may interfere with the action of certain drags. 

Dosage recommendations for antacids vary and range from hourly dosing to administration on an as-needed basis. In general, antacids have a short duration of action, which requires frequent administration throughout the day to provide continuous acid neutralization. 

Chewable Tablets. It has already been noted that most elderly patients experience a decrease in their ability to chew efficiently [125,137,138,143]. Therefore, by virtue of their design, chewable tablets are not often recommended for use by elderly patients (particularly those who are edentulous) 155-163,164], Most chewable formulations also rely on an adequate amount of chewing action to obtain full release of their ingredients (e.g., chewing promotes the foaming action provided by some chewable antacid products). So, aside from being difficult form the elderly patient to use, full benefit of a chewable dosage form may not be achieved by these patients. Additionally, the use of chewable tablets by denture wearers may cause local irritation in the oral cavity [155]. 

The familiar fizzing action that occurs as an antacid tablet dissolves in water is the result of a chemical reaction involving the ingredients in the tablet. 

Each Alka-Seltzer tablet contains 1916 mg of sodium bicarbonate, 1000 mg of citric acid (Fig. 9.1.2), and 325 mg of aspirin or acetylsalicylic acid (Fig. 9.1.3). Bromo Seltzer also contains sodium bicarbonate and citric acid as well as acetaminophen (Fig. 9.1.4). Several equilibria describe the action of bicarbonate-based antacid tablets. First of all, sodium bicarbonate dissolves completely in aqueous solution to generate sodium ions and bicarbonate ions ... 

It may seem strange that we would ever want to perform an experiment of this kind. First of all it would be used in the event of a slow reaction taking place in the reaction flask. Perhaps the sample is not dissolved completely, and addition of the titrant causes dissolution to take place over a period of minutes or hours. Adding an excess of the titrant and back-titrating it later would seem an appropriate course of action in a case of this kind. An example would be the determination of the calcium carbonate in an antacid tablet (Experiment 13). 

Since food has a buffering effect, antacids are taken between meals (e.g., 1 and 3 h after meals and at bedtime). Nonabsorbable antacids are preferred. Because Mg(OH)2 produces a laxative effect (cause osmotic action, p. 170, release of cholecystokinin by Mg, or both) and Al(OH)3 produces constipation (cause astringent action of AP, p. 178), these two antacids are frequently used in combination. 

Uses Rx prevent osteoporosis male female, Rx steroid-induced osteoporosis, Paget Dz Action -1- N1 abnormal bone resorption Dose Osteoporosis Rx 10 mg/d PO or 70 mg qwk Fosamax plus D 1 tab qwk Steroid-induced osteoporosis Rx 5 mg/d PO Prevention 5 mg/d PO or 35 mg qwk Paget Dz 40 mg/d PO Caution [C, ] Not OK if CrCl <35 mLAnin, w/ NSAID use Contra Esophageal anomalies, inability to sit/stand upright for 30 min, X Ca Disp Tabs, soln SE GI disturbances, esophageal irritation, HA, pain, jaw osteonecrosis (w/ dental procedures, chemo) Interactions -1- Absorption W7 antacids, Ca supls, Fe, food T risk of upper GI bleed W/ ASA NSAIDs EMS May cause cardiac conduction abnormalities d/t T Ca T risk of jaw fractures esp w/ dental procedures OD May cause hypocalcemia and adverse upper-GI effects milk or antacids can be given to bind alendronate... 

Alginic Acid + Aluminum Hydroxide Magnesium Tnsilicate (Gaviscon) [Antacid] [OTC] Uses Heartburn hiatal hernia pain Action Protective layer blocks gastric acid Dose 2—4- tabs or 15-30 mL PO qid followed by H2O Caution [B, -] Avoid in renal impair or Na -restricted diet Disp Tabs, susp SE D, constipation Interactions T Absorption OF tetracyclines EMS None OD May cause constipation, loss of appetite, muscle weakness, and peripheral edema symptomatic and supportive... 

Aluminum Hydroxide + Magnesium Carbonate (Gaviscon Extra Strength/ Liquid) [OTC] [Antacid/Aluminum Magnesium Salts] Uses Relief of heartburn, acid indigestion Action Neutralizes gastric acid Dose Adults. 15-30 mL PO pc hs Peds. 5-15 mL PO qid or PRN avoid in renal impair Caution T Mg (w/ renal insuff) [C, ] Disp Liq, chew tabs SE Constipation, D Interactions In addition to AlOH effects OF histamine blockers, hydantoins, nitrofurantoin, phenothiazines, ticlopidine, T effects OF... 

Bisacodyl (Dulcolox) [OTC] [Stimulant Laxative] Uses Con ti-pation preop bowel pr Action Stimulates pmstalsis Dose Adults. 5-15 mg PO or 10 mg PR PRN Peds. <2y 5 mg PR PRN >2 y 5 mg PO or 10 mg PR PRN (do not chew tabs or give w/in 1 h of antacids or milk) Caution [B, ] Contra Acute abd or bowel obst, appendicitis, gastroentmtis Disp Tabs, supp, enema soln... 

Calcium Acetate (PhosLo) [Calcium Supplement/ Anti arrhythmic/Mmeral/ Electrolyte] Uses ESRD-associated hyper-phos-phatemia Action Ca " supl w/o aluminum to X P04 absorption Dose 2-4 tabs PO w/ meals Caution [C, ] Contra t Ca Disp Gelcap SE Can t Ca, hypophosphatemia, constipation Interactions t Effects OF quinidine X effects W/ large intake of dietary fiber, spinach, rhubarb X effects OF atenolol, CCB, etidronate, tetracyclines, fluoroquinolones, phenytoin, Fe salts, thyroid hormones EMS Pts have reduced renal Fxn, monitor ECG for signs of electrolyte disturbances OD S/Sxs of hypercalcemia (confusion, weakness, GI upset, constipation, N, V, and cardiac arrhythmias) give IV fluid for diuresis symptomatic and supportive Calcium Carbonate (TumS/ Alka Mints) [Antacid/ Calcium Supplement/Mineral/ Electrolyte] [OTC] Uses Hyperacidity associated w/ peptic ulcer Dz, hiatal hernia, etc Action Neutralizes gastric acid Dose 500 mg—2 g PO PRN -1- in renal impair Caution [C, ] Disp Chew tabs, susp SE t -1- PO constipation Interactions X Effect OF tetracyclines, fluo-... 

---