ANTIULCERS AND ANTI ACID DRUGS GET DEEP UNDESTANDING

AntiUlcers and Anti Acid Drugs

 STEP 2: Indications of Antacids and Antiulcer Drugs

Antacids are weak bases that react with gastric hydrochloric acid to form a salt and water.

Antacids have been used for centuries in the treatment of acid-peptic disorders Antacids (usually containing aluminium or magnesium Compounds) can often relieve symptoms in ulcer dyspepsia and in non-erosive gastro-oesophageal reflux.

 Antacids are also sometimes used in functional (non-ulcer) dyspepsia. 

Aluminium hydroxide is used in management of dyspepsia and hyperphosphatemia.

Magnesium trisilicate is used in management of dyspepsia.

Anti-Ulcer Drugs:

A)Histamin (H2-receptor) antagonists (e.g. cimetidine, famotidine and ranitidine).

These drugs are indicated for gastroesophageal reflux disease (GERD), peptic ulcer disease, non-ulcer dyspepsia, acute gastritis, Zollinger-Ellison Syndrome and prevention of bleeding from stress-related gastritis.

B)Proton Pump Inhibitors (PPI) (e.g. Omeprazole and Lansoprazole).

These drugs are indicated for gastroesophageal reflux disease (GERD), H pylori-associated ulcers, NSAID-associated ulcers, Prevention of re-bleeding from peptic ulcers, nonulcer dyspepsia, acute gastritis, prevention of stress-related mucosal bleeding, gastrinoma and other hypersecretory conditions.

C)Drugs for Treatment of Helicobacter Pylori.

Omeprazole + Amoxycillin + plus Metronidazole.

Or

Lansoprazole + Clarithromycin + plus Tinidazole.

Then Lansoprazole for one month.

STEP 3: Contraindications of Antacids and Antiulcer Drugs

Antacids

a)Magnesium Carbonate is contraindicated in hypophosphatemia.

b)Magnesium trisilicate is contraindicated in hypophosphatemia.

c)Aluminium hydroxide is contraindicated in hypophosphatemia, neonates and infants.

Both magnesium and aluminum are absorbed and excreted by the kidneys. Hence, patients with renal insufficiency should not take these agents long-term

STEP 4: Dose, Dosage and Course of Antacids and Antiulcer Drugs:

A)Antacids

Magnesium trisilicate 250 mg 1 to 2 tablets chewed when required.

Magnesium Trisilicate Mixture/ Suspension 5% each of magnesium trisilicate,10 to 20 mL in water 3 times daily or as required.

B)Dried aluminium hydroxide 220 mg/5 Ml: 10 to 20 mL 3 times daily, 20 to 60 minutes after meals, and at bedtime or when required.

Antiulcer Drugs:

A)H-2 Antagonists

1)Cimetidine 400 mg twice daily (with breakfast and at night) or 800 mg at night (benign gastric and duodenal ulceration) for at least 4 weeks (6 weeks in gastric ulceration, 8 weeks in NSAID-associated ulceration). When necessary the dose may be increased to 400 mg four times daily.

Cimetidine is used in Prophylaxis of stress ulceration, 200 to 400 mg every 4 to 6 hours.

2)Ranitidine is administered as 150 mg twice daily or 300 mg at night for 48 weeks in benign gastric and duodenal ulceration, up to 6 weeks in chronic episodic dyspepsia, and up to 8 weeks in NSAID-associated ulceration In duodenal ulcer 300 mg.

Ranitidine can be given twice daily for 4 weeks to achieve a higher healing rate.

 B)Proton Pump Inhibitors:  Lansoprazole in Benign gastric ulcer, 30 mg daily in the morning for 8 weeks Lansoprazole in Duodenal ulcer, 30 mg daily in the morning for 4 weeks; maintenance 15 mg daily

Lansoprazole NSAID-associated duodenal or gastric ulcer, 30 mg once daily for 4 weeks.

Lansoprazole when used in eradication of Helicobacter pylori associated with duodenal ulcer see eradication regimens below.

Omeprazole when used benign gastric and duodenal ulcers,20 mg once daily for 4 weeks in duodenal ulceration or 8 weeks in gastric ulceration; in severe or recurrent cases increase to 40 mg daily; maintenance for recurrent duodenal ulcer, 20 mg once daily.

Omeprazole when used for NSAID-associated duodenal or gastric ulcer and gastro duodenal erosions, 20 mg once daily for 4 weeks, continued for further 4 weeks if not fully healed.

Omeprazole in Duodenal or benign gastric ulcer associated with Helicobacter pylori, see eradication regimens on below.

C)Drugs for Treatment of Helicobacter Pylori 

Omeprazole 40mg once daily+ Amoxycillin 500mg 8 hourly + plus Metronidazole 400mg 8 hourly for 7 days.Or

Lansoprazole 30mg once daily+ Clarithromycin 250mg 12 hourly + plus Tinidazole 500mg once daily for 7 days.  Then Lansoprazole 30mg once daily for one month

STEP 5: Side Effects and Adverse Effects of Antacids and Antiulcer Drugs

Antacids.

Constipation (Aluminium hydroxide)  may produce,Diarrhoea (magnesium hydroxide), Sodium bicarbonate (systemic alkalosis and liberate Co2 causing belching and flatulence)

Antiulcer Drugs

H2-Receptor Antagonists (e.g. cimetidine, famotidine and ranitidine) . H2 antagonists are safe drugs (with an exception of cimetidine to some extent) Adverse effects occur in fewer than 3% of patients and include diarrhoea, headache, fatigue, myalgias, and constipation Mental status changes (confusion, hallucinations, agitation) may occur with administration of intravenous H2 antagonists, especially in patients in the intensive care unit who are elderly or who have renal or hepatic dysfunction.

These events may be more common with cimetidine.Cimetidine when used long-term or in high doses, it may cause gynecomastia or impotence in men and galactorrhea in women.

Alopecia may occur though rarely with cimetidine.

Rapid intravenous infusion may cause bradycardia and hypotension through blockade of cardiac H2 receptors; therefore, intravenous injection should be given over 30 minutes.

Proton Pump Inhibitors (PPI) (e.g. Omeprazole and Lansoprazole):

Proton pump inhibitors are extremely safe and well tolerated.

Diarrhoea, headache and abdominal pain are reported in 1-5% of patients

STEP 6: Interactions and Precautions of Antacids and Antiulcer Drugs

Antacids:

It is usually advisable to avoid concurrent administration of antacids and other drugs. By altering gastric and urinary pH or delaying gastric emptying, antacids can affect rates of dissolution and absorption, bioavailability, and renal elimination of many drugs.

By binding to drugs (for example, tetracycline), Aluminium compounds can form insoluble complexes that are not absorbed On the other hand, antacids can increase the rate of absorption of some drugs, for example levodopa.

Antiulcer Drugs H2-Receptor Antagonists (e.g. cimetidine, famotidine and ranitidine)

Cimetidine can slow metabolism (and thus potentiate the action) of several drugs (for example; warfarin, diazepam, phenytoin, quinidine; carbamazepine, Theophylline, imipramine), sometimes resulting in serious adverse clinical effect.

Negligible interaction occurs with nizatidine and famotidine H-2 antagonists compete with certain drugs (e.g. procainamide) for renal tubular secretion.

All of these agents except famotidine inhibit gastric first-pass metabolism of ethanol, especially in women resulting to increased bioavailability of ethanol thus increased blood ethanol levels

H2-antagonists should not be administered to pregnant women unless absolutely necessary .

The H2 antagonists are secreted into breast milk and may therefore affect nursing infant.

Proton Pump Inhibitors (PPI) (e.g. Omeprazole and Lansoprazole): 

Omeprazole interferes in the oxidation of warfarin, phenytoin, diazepam and cyclosporine.

Lansoprazole is associated with minimal drug interactions

STEP 7: Key Points

Common antacids used are Magnesium trisilicate, magnesium hydroxide and aluminium hydroxide 

Common Antiulcer drugs used are H-2 antagonists (mainly cimetidine and ranitidine) and Proton pump inhibitors (particularly omeprazole and lansoprazole) 

Antiulcer Drugs are associated with significant drug interactions Antacids and Cimetidine may have serious adverse effects Special precaution may be needed when using Antacids and antiulcer drugs 

 

STEP 8:References

Ministry Of Health and Social Welfare. (2013).

Standard Treatment Guidelines & National Essential Medicines List Tanzania Mainland (4th ed.). Dar es salaam, Tanzania government printers.

Robert, L. T., Gary, C.Y., Gary, R.M, Barbara, G. W., Michael, L. (2014). Pharmacotherapy: 

A Pathophysiologic Approach (9th ed.). New York, McGraw-Hill Education. Sally S.R, & Jeanne C.S. (2000). 

Introductory Clinical Pharmacology (6th ed) New York, Lippincott Williams and Wilkins.

 School of Pharmaceutical sciences. (2011). Tanzania Pharmaceutical Handbook (2nd ed.). Dar es Salaam, ARDHI University press. 

The Royal Pharmaceutical Society of Great Britain. (2007).

Martindale: The Extra Pharmacopoeia (5TH ed). London, pharmaceutical press.

The Royal Pharmaceutical Society of Great Britain. (2009).

British National Formulary (59th ed). London, BMJ Group and RPS Publishing

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