Histamine receptor 2 inhibitors
Mechanism Of Action:
Histamine has 2 types of receptors. One is Histamine 1 and other is histamine 2. Activation of histamine 1 receptors produce classic symptoms of inflammation and activation of histamine 2 increase the secretion of HCL by parietal cells in the stomach.
Histamine receptors 2 blockers decrease the acid production by parietal cell in the stomach.
- Cimetidine ( First drug in this class and used less frequently because of numerous drug-drug interactions, inhibits hepatic drug-metabolizing enzymes and it must be taken 4 times a day.)
- Since, it decrease the acid production in the stomach, it is mainly used for the PUD (Peptic ulcer disease)
- H2 blockers are sometimes used to prevent ulcers in people who take NSAIDs long-term (for example, for arthritis).
- GERD (gastroesophgeal reflux disorder)
- Continue to monitor periodic hepatic and renal function tests and CBC, platelets, and electrolyte levels.
- Take at bedtime is it is once a day
- Long-term use can cause gynecomastia, and impotence, in men and breast tenderness in women.
- Avoid taking 1 hr before and after taking antacids. Antacids can reduce the absorption of drugs.
- Dizziness and drowsiness from these drugs may occur. Therefore special precautions should be taken to reduce falls.