Ulcers in the stomach is a condition caused due to sore or breach in the continuity of the mucous membrane or the inner lining of the stomach, duodenum, and rarely in the lower part of the esophagus.
Ulcers in the stomach (Peptic ulcers) are mainly of two types:
- Gastric ulcer
- Duodenal ulcer
Antacids and Antiulcer Drugs: what are they?
As the name indicates, antacids are ‘anti-acids.’ Chemically, the drugs of this class are basic compounds that aid in neutralizing the released gastric acid and raise the pH of gastric contents. Under this condition, pepsin activity gets reduced if the pH rises above 4; since pepsin gets secreted as a complex with an inhibitory terminal part that dissociates below pH 5. The optimum peptic activity is in the pH 2 to 4. This article explains in detail-Ulcers in the stomach, Antacids, and Antiulcer Drugs.
Read more about Gastric ulcer or Duodenal ulcer
How do Antacids work?
Antacids do not decrease acid production but raise the pH more than 4. The potency of an antacid is expressed in terms of its acid-neutralizing capacity (ANC). ANC takes into consideration the rate at which the antacid dissolves and reacts with HCL in the stomach. The drugs under these can thus be differentiated based on their ANC, which helps determine the dosing regimen. This is significant because a single dose of any antacid taken in an empty stomach acts for 30–60 minutes, as the gastric content passes into the duodenum. Antacids may act for a period of 2–3 hours if taken along with meals.
Antacids and Antiulcer Drugs: Different classes
The drugs under this class are categorized as per their action (local or systemic), duration of action, and combination drugs.
Sodium bicarbonate – It is a water-soluble that acts instantaneously. The duration of action is short. It is a potent neutralizer 1 g of this may increase the pH above 7. The use is limited due to side-effects.
These antacids are poorly absorbed and are insoluble basic compounds that react in the stomach to form the corresponding chloride salt. The formed chloride salt reacts with intestinal bicarbonate such that no HCO3– is spared for absorption. As a result, no acid-base disturbances occur. Some of the commonly available OTC antacids are –
- Magnesium hydroxide (Milk of Magnesia) – It has low water solubility. The aqueous suspension (milk of magnesia) of this drug has low OH¯ ions concentration and shows low alkalinity.
- Magnesium trisilicate has low solubility and reactivity potential than other antacids
- Aluminum hydroxide gel (Aldurox tab.)– It is a slow-reacting, bland, and weak antacid. When stored for a long time, it polymerizes into lesser reactive forms. Thus, the ANC of any aluminum hydroxide preparation declines gradually.
- Magaldrate (Stacid tab, ulgel syrup) – It is a hydrated complex of hydroxy magnesium aluminate that primarily reacts rapidly with acid and releases aluminum hydroxide, which reacts slowly. The freshly released aluminum hydroxide remains in an unpolymerized form.
- Calcium carbonate – It is a potent and rapidly acting acid neutralizer. Still, ANC of commercial preparations is less and variable due to variable particle size and crystal structure of the compounds.
Antacid Combinations (Acidin, Almacarb, digene, gelusil,muciane, gelusil liquid)
Combinations of two (or more) antacids are used frequently for therapeutic purposes. These combinations are superior to any single agent on the following accounts:
- Fast-acting (Magnesium hydroxide) and slow-acting (Aluminum hydroxide) acting components yield an immediate and sustained effect.
- Magnesium salts are laxatives, while aluminum salts are constipating. The combination nullifies each other’s actions on bowel movement.
- Gastric-emptying time is minimally affected.
- Combination antacids reduce the dose of individual components; thus, the related systemic toxicity is avoided.
- Indications in which they are preferred.
Antacids are only employed for intercurrent pain relief and acidity and are self-prescribed by the patients. The antacids are used for providing symptomatic relief from Gastroesophageal reflux disease (GERD), acid eructation, and heartburn.
They are not used for peptic ulcers as they were used in the past.
- side effects
- diarrhea or constipation
- flatulence and bloating
- fluid retention
- abdominal cramps
- nausea and vomiting
- rebound acidity
Serious Side Effects (with prolonged use)
- mucosal line damage
- taste bud damage
- natural renal dysfunction
- tongue swelling
- apnea (troubled breathing)
- severe dizziness
- black stool
- irregular heartbeat and palpitations
- systemic alkalosis (in case of systemic antacids)
- known allergy to a specific drug
- severe renal failure or electrolyte disturbances
- GI obstruction
- In patients with hypercalcemia, hyperparathyroidism, and Vit-D overdose
- In patients with hepatic failure
- In patients with severe cardiac abnormalities.
Antiulcer Drugs for treating Ulcers in the stomach
What are Antiulcer Drugs?
As the name suggests, the agents under this drug class are used for the management and treatment of ulcers in the stomach, both peptic and duodenal. Ulcers in the stomach occur when any part of GIT gets directly exposed to the gastric acid and pepsin. The etiology of peptic ulcers is unclear, and several factors are responsible for triggering it. Generally, it is a result of an imbalance between aggressive (pepsin, bile, Helicobacter pylori, acid) and defensive (gastric mucus, bicarbonates, prostaglandins nitric oxide, high mucosal blood flow, innate resistance of the mucosal cells) mechanisms. Thus, the drugs used for ulcers prevent the upregulation of aggressive factors and aid the defensive factors for an overall healing effect.
How do they work?
The antiulcer drugs try to restore the balance between the aggressive and the defensive factors, by directly or indirectly acting upon the physiological pathway involved. The drugs block many pathways that cause the secretion of gastric acid, and another class of drugs aims to provide a protective layer over the damaged area. If the ulcer is caused due to H. pylori, then the antibiotic drug regimen is used to improve the ulcer condition.
Ulcers in the stomach: Classes of Drugs
- Antimicrobial agents
Used as the therapy for patients with peptic ulcer disease, infected with H. pylori. Eradication of the microbe results in the rapid healing of active peptic ulcers and lowers the occurrence rate. Combination therapy with other drugs results in a greater eradication rate.
Drugs – Amoxicillin, bismuth compounds, clarithromycin, metronidazole, tetracycline
2. H2 – Histamine receptor blockers
these agents inhibit gastric acid secretion, particularly effective against nocturnal acid secretion. They block histamine binding to H2 receptors competitively, leading to decreased intracellular signaling molecules for gastric acid release, in turn decreasing the secretion.
3. Proton pump inhibitors (PPI) –
The drugs under this class bind to an enzyme system H+/K+ – ATPase. This system is the proton pump in the parietal cells of the stomach, and the drugs inhibiting it suppresses the secretion of hydrogen ions into the gastric lumen.
4. Prostaglandin analogs
this drug class is less effective than the other for the treatment of Ulcers in the stomach. The drug shows cytoprotective actions only at high doses that inhibit gastric acid secretion.
Drug – misoprostol
5. Anti-muscarinic agents
activation of muscarinic receptor leads to an increase in GI motility and secretion. Thus, drugs antagonizing such an action can be used as an adjunct as a management therapy for ulcers.
Drugs – dicyclomine
these drugs are used as adjunctive therapy to reduce the damage during acid secretion. They provide symptomatic relief and do not cure the cause.
7. Mucosal protective agents
these agents are commonly known as cytoprotective compounds that perform several actions that enhance the mucosal protection mechanisms. Such action results in the prevention of mucosal injury and inflammation and heals the existing Ulcers in the stomach.
Drugs – bismuth subsalicylate, sucralfate
Antacids and Antiulcer Drugs: indications in which they are preferred.
The antiulcer drugs are indicated for the treatment of acute to chronic ulcer, GERD, Zollinger-Ellison Syndrome, gastritis, H. pylori-induced ulcers, duodenal ulcers, gastric ulcers, stress ulcers
- Anti-microbial – GI motility disturbances, gut dysbiosis
- H2 – Histamine receptor blockers – constipation, headache, insomnia, diarrhea, fatigue, muscle pain. Significant side effects – dry mouth, rashes
- Proton pump inhibitors – leucopenia, rashes, abdominal pain, muscle and joint pain, hepatic dysfunction
- Prostaglandin analog – diarrhea, flatulence, dyspepsia, headache, vomiting, pain
- Antimuscarinic agents – cardiac arrhythmias, dry mouth, constipation, urinary retention
- Antacids – the risk of ulcer perforation, belching, rebound acidity, systemic alkalosis
- Mucosal protective agents – constipation (most common), dry mouth, flatulence, headache (cephalalgia)
- Renal dysfunction
- Hepatic dysfunction
- Any known allergy
- Misoprostol is abortifacient hence contraindicated during pregnancy