H2 blockers, used to treat gastrointestinal ulcers and/or reduce stomach acid, may improve survival among people with cancer, especially after colorectal cancer resection.
Cimetidine and other H2 blockers at a glance
Cimetidine and other histamine H2-receptor antagonists, also known as H2 blockers, are used to treat gastrointestinal ulcers and/or reduce stomach acid. They are available both as over-the-counter medications for heartburn and stomach acid and as prescription drugs. Their use in treating cancer is considered off-label.
Some research, mostly small studies, show better cancer survival when people are treated with cimetidine, often around the time of surgery or along with other conventional treatmentsthe cancer care offered by conventionally trained physicians and most hospitals; examples are chemotherapy, surgery, and radiotherapy. The strongest evidence relates to colorectal cancer. Use may also reduce risk of lung cancer, although use of ranitidine—but not other H2 blockers—is linked to higher risk of one type of breast cancer, and people with diabetes have shown a higher risk of lung cancer when using H2 blockers.
CancerChoices ratings for H2 blockers
We rate cimetidine and other H2 blockers on seven attributes, with 0 the lowest rating and 5 the highest. We rate the strength of the evidence supporting the use of cimetidine or other H2 blockers for a medical benefit, such as improving treatment outcomes or managing side effects.
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