Drugs for diarrhoea

WHO defines diarrhoea as 3 or more loose and watery stools in 24 hours of period.

May be due to

  • Decreased water & electrolyte balance
  • Increased secretion by intestinal mucosa
  • Increased luminal osmotic load
  • Inflammation of the mucosa & exudation in lumen.

Principles of management

Most diarrhoeas are self limiting.

Management of diarrhoea depends on establishing the underlying cause & instituting specific therapy.

  • Treatment of fluid depletion
  • Maintenance of nutrition
  • Drug therapy

 

I. REHYDRATION

Hydration must be maintained in all cases of diarrhoea to prevent fluid depletion and shock.

Intravenous rehydration –

  • Needed when fluid loss is severe, >10% body weight.
  • Or when person is not able to take oral fluids.
  • Composition of i.v. fluid –

NaCl – 85 mM = 5 g

KCl – 13 mM = 1 g

NaHCO3 – 48 mM = 4 g

The above in 1 L water or 5% glucose solution .

Oral rehydration –

  • It contains sodium & potassium chloride, trisodium citrate &
  • Glucose helps in absorption of sodium because glucose facilitated sodium reabsorption remains intact even in severe diarrhoea.
  • Trisodium citrate is to prevent acidosis.

 

The Who has formulated a new formula WHO-ORS, in which the concentration of glucose & NaCl as well as total osmolarity is decreased because –

WHO std. formula was used for cholera stools in which loss of Na was more. Now there is a decrease in cholera cases & major cause of diarrhoea now is rotavirus.

It had lead to edema because of high Na content.

II. MAINTENANCE  OF NUTRITION

Fasting decreases the brush border disaccharide enzymes & reduces absorption of salt, water & nutrients. This may lead to malnutrition is diarrhoea is prolonged or recurrent.

 

III. DRUG THERAPY

 

1] Antimicrobials in Diarrhoea :-

  • These drugs have a limited role because bacterial pathogen is responsible for only a fraction of cases.
  • Antimicrobials are useful in slightly loose, smaller volume stools, frequently with mucous or blood, and associated with fever, abdominal pain or vomiting .
  • These are generally caused by organisms like –

Shigella, enteropathogenic E.coli, Campylobacter jejuni, salmonella typhimurim, E.histolytica, etc.

 

2] Probiotics in diarrhoea.

  • These are microbial cell preparations, either live cultures or lyophilised powders.
  • They restore & maintain healthy gut flora
  • Recolonization of gut by non pathogenic, mostly lactic acid forming bacteria & yeast is believed to help restore the balance of gut flora.
  • Natural curd / yoghurt is an abundant source of lactic acid producing organisms, which serve as probiotics.
  • Probiotics reduce antibiotic associated diarrhoea, acute infective diarrhoea & risk of traveller’s diarrhoea.

 

Non – specific antidiarrhoeal drugs

a. Absorbents

b. Antisecretory drugs

c. Antimotility drugs

 

a] Absorbents –

– These are colloid bulk forming agents like ispaghula, methyl cellulose, etc which absorb water & swell.

– They modify the consistency & frequency & give an impression of improvement, but do not reduce water & electrolyte balance.

 

b] Antisecretory drugs –

Racecadotril:

  • It is an encephalinase inhibitor
  • Prevents degradation of endogenous enkephalins which are mainly opioid receptor agonists.
  • Decreases intestinal hypersecretion by lowering mucosal cAMP due to enhanced enkephalin action.

Octreotide :

  • Long acting somatostatin analogue
  • Used to decrease secretory diarrhoea & other symptoms of carcionoid syndrome & vasoactive intestinal peptide tumors (VIPoma)
  • In high doses, it is useful for treatment of diarrhoea due to vagotomy & AIDS.

Others like bismuth subsalicylate, anticholinergics, opioids are used.

 

c] Antimotility drugs –

– These are opioid drugs which increase small bowel tone & segmenting activity, reduce propulsive movements & diminish intestinal secretions.

– They afford only symptomatic relief in diarrhoea.

Loperamide :

  • It is a non-addictive over the counter drug for diarrhoea

Codeine, Diphenoxylate may also be used.

Note :- Antimotility drugs are limited to non-infective diarrhoea, because they delay the clearance of pathogen from intestine.

 

 

Also, drugs for inflammatory bowel disease are used in the treatment of diarrhoeas.


 

Contributed by – Soumya Khot, Jay Shah.

 

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