Indications And Clinical Uses: To test the ability of the gastric mucosa to produce hydrochloric acid.
Contra-Indications: The gastric histamine test is contraindicated in patients with a history of hypersensitivity to histamine products, in patients with hypotension, severe hypertension, vasomotor instability, bronchial asthma (past or present), urticaria (past or present), or severe cardiac, pulmonary or renal disease.
Precautions: Attacks of severe asthma or other serious allergic conditions may be precipitated. The possible benefit that may be derived from the gastric histamine test should be carefully weighed against the serious untoward reactions that may develop in patients with allergic diseases. Small doses by any route of administration may precipitate asthma in patients with bronchial disease. Use the utmost caution in administering histamine to such patients. When histamine phosphate is administered, pull back on the syringe plunger before the injection is made to be sure the end of the needle is not in a blood vessel. Avoid accidental introduction into a vein or artery. Epinephrine HCl 1:1 000 aqueous solution, should be immediately available to counteract the effects of histamine.
Pregnancy and Lactation: The safety of histamine phosphate for use during pregnancy or lactation has not been established. However, based on histamine’s known ability to contract uterine muscle, exposure or repeated doses should be avoided. Therefore, the benefits must be weighed against its possible hazards to the mother and child.
The risk/benefit ratio must be carefully weighed when considering the use of the gastric histamine test in patients with pheochromocytoma.
Histamine increases the acid of the gastric juice and may cause symptoms of peptic ulcer. A large dose of histamine may cause severe occipital headache, blurred vision, anginal pain, a rapid drop in blood pressure and cyanosis of the face. Overdosage may cause severe symptoms, including circulatory collapse, shock, and even death. Monitor the blood pressure and pulse carefully during injection of histamine.
Use with caution in elderly patients and in patients with any cardiac abnormality.
Adverse Reactions: Average or large doses of histamine may include such local reactions as erythema and edema and/or such systemic reactions as flushing, dizziness, headache, bronchial constriction, dyspnea, visual disturbances, faintness, syncope, urticaria, asthma, marked hypertension or hypotension, palpitation, tachycardia, nervousness, abdominal cramps, nausea, diarrhea, vomiting, metallic taste, local or generalized allergic manifestations, or collapse with convulsions. These reactions may be serious and excessive dosage can produce collapse and shock, and may be fatal.
Symptoms And Treatment Of Overdose: Symptoms: See Adverse Effects.
Treatment: If accidental overdosage is discovered early, temporary application of a tourniquet proximally to the injection site may be tried to slow down the absorption of the drug. Antidotes to histamine are the following: epinephrine HCl, 0.1 to 0.5 mL of a 1:1 000 aqueous solution, given s.c. in case of emergency due to severe reactions; an antihistamine preparation, given orally in case of mild allergic reactions caused by the usual dose of the drug.
Dosage And Administration: Gastric Acid Test: The patient fasts for 12 hours. A plastic duodenal tube is passed into the stomach, the gastric content withdrawn, and its acidity determined. Care should be taken to prevent the patient from swallowing salivary secretions during administration of the test results. The alkalinity of the saliva may interfere with the test results. Histamine phosphate 500 to 750 g is injected s.c.
Gastric content is again removed after 5 minutes and at 15-minute intervals thereafter on 3 occasions.
The volume and acidity of each specimen are determined. If no acidity is detected, a maximum histamine stimulation test can be performed using 40 g/kg histamine phosphate s.c. Pulse rate and blood pressure should be determined immediately after histamine injection.
Availability And Storage: Each mL contains: histamine phosphate USP 1 mg. Nonmedicinal ingredients: sodium chloride. Ampuls of 1 mL, boxes of 10. Store between 15 and 30°C. Protect from light. Do not freeze.
HISTAMINE Bioniche Histamine Phosphate Diagnostic Aid