Gastroesophageal reflux disease (GERD)

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Chapter: Essential pharmacology : Drugs For Emesis, Reflux And Digestive Disorders

It is a very common problem presenting as ‘heartburn’, acid eructation, sensation of stomach contents coming back in food-pipe, especially after a large meal, aggravated by stooping or lying flat.


GASTROESOPHAGEAL REFLUX DISEASE (GERD)

 

It is a very common problem presenting as ‘heartburn’, acid eructation, sensation of stomach contents coming back in food-pipe, especially after a large meal, aggravated by stooping or lying flat. Some cases have an anatomical defect (hiatus hernia) but majority are only functional (LES relaxation in the absence of swallowing). Repeated reflux of acid gastric contents into lower 1/3rd of esophagus causes esophagitis, erosions, ulcers, pain on swallowing, dysphagia strictures, and increases the risk of esophageal carcinoma.

 

The primary barrier to reflux is the tone of LES which can be altered by several influences:

 

Inherent toneof sphincteric smooth muscle.

Hormonal: gastrin increases, progesterone decreases (reflux is common in pregnancy).

Neurogenic: vagus is motor to the sphincter, promotes esophageal peristalsis.

Dietary: fats, alcohol, coffee, chocolates decrease, while protein rich foods increase LES tone.

Drugs: anticholinergics, tricyclic antidepressants, Ca2+ channel blockers, nitrates reduce LES tone.

Smoking:  relaxes  LES.

 

Delayed gastric emptying and increased intragastric pressure may overcome the LES barrier to reflux. GERD is a wide spectrum of conditions from occasional heartburn to persistent incapacitating reflux which interferes with sleep and results in esophageal, laryngotracheal and pulmonary complications. Severity of GERD may be graded as:

 

Stage 1: occasional heartburn (<3 episodes/week), mostly only in relation to a precipitating factor, mild symptoms, no esophageal lesions.

 

Stage 2: > 3 episodes/week of moderately severe symptoms, nocturnal awakening due to regurgitation, esophagitis present or absent.

 

Stage 3: Daily/chronic symptoms, disturbed sleep, esophagitis/erosions/stricture, symptoms recur soon after treatment stopped.

 

Though GERD is primarily a g.i. motility disorder, acidity of gastric contents is the most important aggressive factor in causing symptoms and esophageal lesions. The functional abnormality is persistent; dietary and other lifestyle measures (light early dinner, raising head end of bed, weight reduction and avoidance of precipitating factors) must be taken.

 

Treatment of GERD is individualized according to severity and stage of the disorder.

 

The site and mechanism of benefit afforded by different classes of drugs in GERD is depicted in Fig. 47.3.

 


 

1. Proton Pump Inhibitors (PPIs)

 

These are the most effective drugs, both for symptomatic relief as well as for healing of esophageal lesions. Intragastric pH >4 maintained for ~18 hr/day is considered optimal for healing of esophagitis. This level of acid suppression can be consistently achieved only by PPIs. Therefore, PPIs are the drugs of choice for all stages of GERD patients, particularly stage 2 and 3 cases. Symptom relief is rapid and 80–90% esophageal lesions heal in 4–8 weeks. Dose titration is needed according to response in individual patients. Some patients require twice daily dosing. Prolonged (often indefinite) therapy is required in chronic cases because symptoms recur a few days after drug stoppage. PPIs have no effect on LES tone.

 

2. H2 Blockers

 

They reduce acidity of gastric contents and have no effect on LES tone. H2 blockers cause less complete acid suppression than PPIs—adequate symptom relief is obtained only in mild cases; healing of esophagitis may occur in 50–70% patients. H2 antagonists are indicated in stage1 cases, or as alternative to PPIs in stage 2 or 3. The daily dose should be divided into 2–3 portions for better response.

 

3. Antacids

 

Their use in GERD is limited to occasional or intercurrent relief of heartburn. Antacids are no longer employed for healing of esophagitis.

 

4. Sodium Alginate

 

It forms a thick frothy layer which floats on the gastric contents like a raft may prevent contact of acid with esophageal mucosa. It has no effect on LES tone. Combination of alginate with antacids may be used in place of antacids alone, but real benefit is marginal.

 

REFLUX LIQUID: Sod. alginate 200 mg + alum. hydrox. gel 300 mg + mag. trisilicate 125 mg/10 ml susp; REFLUX FORTE Aginic acid 20 mg + sod. bicarb. 70 mg + alum. hydrox. 300 mg tab; GAVISCON Alginic acid 500 mg + mag. trisilicate 25 mg + alum. hydrox. gel 100 mg + sod. bicarb. 170 mg tab.

 

5. Prokinetic Drugs

 

Metoclopramide, cisapride and other prokinetic drugs may relieve regurgitation and heartburn by increasing LES tone, improving esophageal clearance and facilitating gastric emptying, but do not affect gastric acidity or promote healing of esophagitis. Symptom control afforded by prokinetic drugs is inferior to that by PPIs/H2 blockers. Their use in GERD has declined. Prokinetic drugs are occasionally added to PPI/H2 blocker therapy, but whether this improves outcome is not clear.

 

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