Drug Groups

approved

Description

Histamine stimulates gastric gland secretion, causing an increased secretion of gastric juice of high acidity. This action is probably due mainly to a direct action on parietal and chief gland cells.

Indication

Histamine phosphate is indicated as a diagnostic aid for evaluation of gastric acid secretory function.

Pharmacology

Histamine stimulates gastric gland secretion, causing an increased secretion of gastric juice of high acidity. This action is probably due mainly to a direct action on parietal and chief gland cells.

Toxicity

LD₅₀=807 mg/kg (mouse, oral). Side effects can lead to hypertension, hypotension, headache, dizziness, nervousness and tachycardia. Large overdoses can lead to seizures.

Affected Organisms

Biotransformation

Primarily hepatic. Histamine is rapidly metabolized by methylation and oxidation. Methylation involves ring methylation and catalyzation by the enzyme histamine-N-methyltransferase, producing N-methylhistamine, which is mostly converted to N-methyl imidazole acetic acid. 2 to 3% excreted as free histamine, 4 to 8% as N-methylhistamine, 42 to 47% as N-methyl imidazole acetic acid, 9 to 11% as imidazole acetic acid, and 16 to 23% as imidazole acetic acid riboside

Absorption

Readily absorbed after parenteral administration

External Links