VPT 321: Veterinary Neuropharmacology (2+1) copy 1

USES OF HISTAMINE

• Histamine does not have any clinical use.
• It was used for the diagnosis of :
  • In pheochromocytoma (tumour of the adrenal medulla) histamine causes a rise in blood pressure after a dose of histamine in these patients instead of the fall in blood pressure in normal individuals.
  • Achlorhydria (lack of hydrochloric acid secretion in the stomach) – for this purpose H₂ agonists like 4-methyl histamine or diamprit, or pentagastrin are preferred because histamine has pharmacological actions on the other systems when given for this purpose and alarming side effects may be produced.
  • Integrity of sensory innervation and circulatory competency by testing for the triple response. (Eg: Leproitic spots)
• Repeated injections of histamine has also been attempted to desensitize patients with allergy.
• Cromolyn sodium (Sodium cromoglycate)
  • This drug inhibits the release of histamine and other substances that are released during allergy.
  • Stabilizes the mast cell membrane  and prevents degranulation of mast cells following antigen-antibody reaction. 
  • It is useful in the prophylaxis of asthma.
  • It is not effective in patients with asthma having an allergic component.
  • It is not effective after exposure and is not useful in acute asthmatic attack.
  • It is available as dry powder for inhalation, solution for inhalation and as eye drops.