Name of the Antacids
- Magnesium hydroxide
- Aluminium hydroxide
- Calcium carbonate
1.Magnesium hydroxide
| Magnesium hydroxide |
| Availability: Liquid: 400 mg/5 ml Liquid concentrate: 800 mg/5 ml Tablets (chewable): 300 mg |
| Indications and dosages Mild magnesium deficiency Adults: 1 g (2 ml of 50% sulfate solution) I.M. q 6 hours for four doses Severe hypomagnesemia Adults: 250 mg (2 mEq)/kg (sulfate) I.M. within 4-hour period, or 5 g (approximately 40 mEq) in 1 liter 5% dextrose injection or 0.9% sodium chloride solution by I.V. infusion over 3 hours Hypomagnesemia treatment Adults and children: Dosage individualized based on severity of deficiency; may give citrate, gluconate, hydroxide, oxide, or sulfate. Hypomagnesemia prophylaxis Adults and children: Dosage based on normal recommended daily magnesium intake; may give citrate, gluconate, hydroxide, oxide, or sulfate Supplemental magnesium in total parenteral nutrition (TPN) Adults: 8 to 24 mEq/day (sulfate) by I.V. infusion, added to TPN solution Constipation Adults and children ages 12 and older: 15 g (sulfate granules) in 240 ml water; or 30 to 60 ml/day P.O. (hydroxide) given with water; or a single dose of 10 to 30 ml P.O. (hydroxide concentrate); or one bottle of oral solution (citrate), as directed Children ages 6 to 11: 5 to 10 g (sulfate granules) in 120 ml water; or a single dose of 2.5 to 5 ml P.O. (sulfate) in a half-glass of water; or 15 to 30 ml P.O. daily (hydroxide) given with water; or a single dose of 7.5 to 15 ml P.O. (hydroxide concentrate); or three to four tablets (hydroxide); or 50 to 100 ml, as directed, of oral solution (citrate) Children ages 2 to 5: Single dose of 5 to 15 ml P.O. (hydroxide); or 2.5 to 7.5 ml P.O. daily (hydroxide concentrate); or one to two tablets (hydroxide); or 4 to 12 ml oral solution (citrate), as directed Indigestion Adults and children ages 12 and older: 5 to 15 ml P.O. (hydroxide liquid) up to q.i.d. with water; or 2.5 to 7.5 ml P.O. (hydroxide liquid concentrate) up to q.i.d. with water; or 622 to 1,244 mg P.O. (hydroxide tablets) up to q.i.d.; or 400 to 800 mg P.O. (oxide tablets) daily To prevent and control seizures in preeclampsia or eclampsia Adults: 4 to 5 g 50% sulfate solution I.M. q 4 hours, as necessary; or 4 g 10% to 20% sulfate solution I.V., not to exceed 1.5 ml/minute of 10% solution; or 4 to 5 g I.V. infusion in 250 ml of 5% dextrose or sodium chloride solution, not to exceed 3 ml/minute Acute nephritis to control hypertension, encephalopathy, and seizures in children Children: 100 mg/kg 50% sulfate solution I.M. q 4 to 6 hours as needed; or 20 to 40 mg/kg 20% solution I.M., repeated as necessary |
Mechanism of Action :
Increases osmotic gradient in small intestine, which draws water into intestines and causes distention. These effects stimulate peristalsis and bowel evacuation. In antacid action, reacts with hydrochloric acid in stomach to form water and increase gastric pH. In anticonvulsant action, depresses CNS and blocks transmission of peripheral neuromuscular impulses.
Metabolism &Elimination :
Bioavailability: 15-30%
Onset: 0.5-6 hr (laxative)
Excretion: Urine (up to 30% as absorbed magnesium), feces (as unabsorbed drug)
Administration
- Be aware that magnesium sulfate injection is a high-alert drug.
- Know that I.V. use is reserved for lifethreatening seizures.
- When giving magnesium sulfate I.V., don’t exceed concentration of 20% or infusion rate of 150 mg/minute, except in seizures caused by severe eclampsia. Too-rapid I.V. infusion may cause hypotension and asystole.
- When giving magnesium sulfate I.M. to adults, use concentration of 25% to 50%; when giving to infants and children, don’t exceed 20%
Contraindications
- Hypermagnesemia
- Heart block
- Myocardial damage
- Active labor or within 2 hours of delivery
Precautions :
- Renal insufficiency, abdominal pain, nausea and vomiting, rectal bleeding, anuria, hypocalcemia
- Pregnant patients
Adverse reactions
- CNS (with I.V. use): confusion, decreased reflexes, dizziness, syncope, sedation, hypothermia, paralysis
- CV (with I.V. use): hypotension, arrhythmias, circulatory collapse
- GI: nausea, vomiting, cramps, flatulence, anorexia
- Metabolic: hypermagnesemia, hypocalcaemia
- Musculoskeletal (with I.V. use): muscle weakness, flaccidity Respiratory: respiratory paralysis
- Skin: diaphoresis
- Other: allergic reaction, injection site reaction, laxative dependence (with repeated or prolonged use)
Patient monitoring
- When giving prolonged or repeated I.V. infusions, assess patellar reflex and monitor for respiratory rate of 16 breaths/minute or more.
- With I.V. use, monitor blood magnesium level (desired level is 3 to 6 mg/ dl or 2.5 to 5 mEq/L). Check for signs and symptoms of magnesium toxicity (hypotension, nausea, vomiting, ECG changes, muscle weakness, mental or respiratory depression, coma). Keep injectable calcium on hand to counteract magnesium toxicity.
- Monitor urine output, which should measure 100 ml or more every 4 hours.
- If I.V. magnesium was given before delivery, assess neonate for signs and symptoms of magnesium toxicity, such as neuromuscular or respiratory depression.
- Monitor electrolyte levels and liver function tests.
Patient teaching
- Teach patient about adverse reactions. Instruct him to report symptoms that occur during I.V. administration.
- Advise patient to consult prescriber before using magnesium if he’s taking other drugs. Magnesium may delay or enhance absorption of other drugs.
- Inform patient that repeated or prolonged use of magnesium citrate, hydroxide, or sulfate may cause laxative dependence. Inform him that healthy diet and exercise can reduce need for laxatives.
- Tell pregnant female to make sure prescriber knows she is pregnant before taking drug.
- As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.
2.Aluminium hydroxide
| Aluminium hydroxide |
| Availability: oral suspension 320mg/5mL |
| Indications and Dosages To treat hyperacidity associated with gastric hyperacidity, gastritis, hiatal hernia, peptic esophagitis, and peptic ulcers; to prevent phosphate renal calculus formation; to reduce hyperphosphatemia in chronic renal failure ALUMINUM CARBONATE CAPSULES, SUSPENSION, TABLETS Adults. 2 capsules or tablets or 10 ml suspension every 2 hr up to 12 times daily p.r.n. ALUMINUM HYDROXIDE CAPSULES, SUSPENSION, TABLETS Adults. 500 to 1,500 mg as capsules or tablets in divided doses 3 to 6 times daily, taken between meals and at bedtime; 5 to 30 ml as suspension, p.r.n., taken between meals and at bedtime |
Mechanism of Action
Neutralizes or reduces gastric acidity, increasing stomach and duodenal alkalinity. Protects stomach and duodenum lining by inhibiting pepsin’s proteolytic activity. Binds with phosphate ions in intestine to form insoluble aluminum-phosphate compounds, which lower blood phosphate level.
Contraindications
Hypersensitivity to aluminum
Pharmacokinetics
- Absorbed aluminum is eliminated in the urine (0.1-0.5 mg of Al in aluminum-containing antacid is absorbed from standard daily doses of antacid)
- Insoluble, poorly absorbed Al salts in the intestines: hydroxides, carbonates, phosphates and fatty acid derivatives, are excreted in feces
Adverse Reactions
- CNS: Encephalopathy
- GI: Constipation, intestinal obstruction, white-speckled stool
- MS: Osteomalacia, osteoporosis
- Other: Aluminum accumulation in serum, bone
Nursing Considerations
- Don’t give aluminum hydroxide within 1 to 2 hours of other oral drugs.
- Know that two 0.6-g aluminum hydroxide tablets can neutralize 16 mEq of acid.
- Monitor patient’s serum levels of sodium, phosphate, and other electrolytes, as appropriate.
Patient Teaching
- Instruct patient to chew tablets thoroughly before swallowing and then to drink a full glass of water.
- Warn patient not to take maximum dosage for more than 2 weeks unless prescribed because doing so may cause stomach to secrete excess hydrochloric acid.
- Teach patient to prevent constipation with a high-fiber diet and increased fluid intake (2 to 3 L daily), if appropriate.
- If patient takes other prescription drugs, advise him to notify prescriber about thembefore taking aluminum because of risk of interactions.
- Advise patient to notify prescriber if symptoms worsen or don’t subside
3.Calcium carbonate
| Calcium carbonate |
| Availability: Calcium carbonate— Capsules: 1,250 mg Lozenges: 600 mg Oral suspension: 1,250 mg Powder: 6.5 g Tablets: 650 mg, 1,250 mg, 1,500 mg Tablets (chewable): 750 mg, 1,000 mg, 1,250 mg Tablets (gum): 300 mg, 450 mg, 500 mg |
| Indications and dosages Hypocalcemia emergency Adults: 7 to 14 mEq I.V. of 10% calcium gluconate solution, 2% to 10% calcium chloride solution, or 22% calcium gluceptate solution Children: 1 to 7 mEq calcium gluconate I.V. Infants: Up to 1 mEq calcium gluconate I.V. Hypocalcemia tetany Adults: 4.5 to 16 mEq calcium gluconate I.V., repeated as indicated until tetany is controlled Children: 0.5 to 0.7 mEq/kg calcium gluconate I.V. three to four times daily as indicated until tetany is controlled Neonates: 2.4 mEq/kg calcium gluconate I.V. daily in divided doses Cardiac arrest Adults: 0.027 to 0.054 mEq/kg calcium chloride I.V., 4.5 to 6.3 mEq calcium gluceptate I.V., or 2.3 to 3.7 mEq calcium gluconate I.V. Children: 0.27 mEq/kg calcium chloride I.V., repeated in 10 minutes if needed. Check calcium level before giving additional doses Magnesium intoxication Adults: Initially, 7 mEq I.V.; subsequent dosages based on patient response Exchange transfusions Adults: 1.35 mEq calcium gluconate I.V. with each 100 ml of citrated blood Hyperphosphatemia in patients with end-stage renal disease Adults: Two tablets P.O. daily, given in divided doses t.i.d. with meals. May increase gradually to bring serum phosphate level below 6 mg/dl, provided hypercalcemia doesn’t develop. |
Mechanism of Action :
Increases serum calcium level through direct effects on bone, kidney, and GI tract. Decreases osteoclastic osteolysis by reducing mineral release and collagen breakdown in bone.
Metabolism &Elimination:
Absorption
- Bioavailability: 25-35%; food increases absorption 10-30%; antacid action dependent on gastric emptying time
- Peak plasma time: 20-60 min (fasting state); up to 3 hr (ingested 1 hr after meals)
Distribution
Protein bound: 45%
Elimination
- Renal clearance: 50-300 mg/day
- Excretion: Feces, as unabsorbed calcium (80%); urine (20%)
Administration
- When infusing I.V., don’t exceed a rate of 200 mg/minute.
- Keep patient supine for 15 minutes after I.V. administration to prevent orthostatic hypotension.
- Administer P.O. doses 1 to 11 ⁄2 hours after meals.
- Know that I.M. or subcutaneous administration is never recommended.
- Be aware that I.V. route is preferred in children.
- Be alert for extravasation, which causes tissue necrosis
Adverse reactions
- CNS: headache, weakness, dizziness, syncope, paresthesia
- CV: mild blood pressure decreases, bradycardia, arrhythmias, cardiac arrest (with rapid I.V. injection)
- GI: nausea, vomiting, diarrhea, constipation, epigastric pain or discomfort
- GU: urinary frequency, renal calculi Metabolic: hypercalcemia
- Musculoskeletal: joint pain, back pain Respiratory: dyspnea
- Skin: rash
- Other: altered or chalky taste, excessive thirst, allergic reactions (including facial flushing, swelling, tingling, tenderness in hands, and anaphylaxis)
Patient monitoring
- Monitor calcium levels frequently, especially in elderly patients
Patient teaching
- Instruct patient to consume plenty of milk and dairy products during therapy.
- Refer patient to dietitian for help in meal planning and preparation.
- As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, and foods mentioned above.
REFERENCES
- Robert Kizior, Keith Hodgson, Saunders Nursing Drug handbook,1st edition 2024, Elsevier Publications. ISBN-9780443116070
- McGraw Hill- Drug Handbook, Seventh Edition, 2013, McGraw Hill Education Publications,9780071799430.
- April Hazard, Cynthia Sanoski, Davi’s Drug Guide for Nurses -Sixteenth Edition 2019, FA Davis Company Publications,9780803669451.
- Jones and Bartlet, Pharmacology for Nurses, Second Edition, 2020, Jones and Bartlet Learning Publications, ISBN 9781284141986.
- Nursebro.com, Search – Nursebro
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