Pharmacologic class (EPC) · 8 drug pages

Histamine-2 receptor antagonist: adverse event reports filed with FDA

270,928 reports list a drug in this class as a suspect or interacting product, 2004–2026.

Read first · FDA's statement on these data

Adverse event reports submitted to FDA do not undergo extensive validation or verification. Therefore, a causal relationship cannot be established between product and reactions listed in a report. While a suspected relationship may exist, it is not medically validated and should not be the sole source of information for clinical decision making or other assumptions about the safety or efficacy of a product. Additionally, it is important to remember that adverse event reports represent a small percentage of total usage numbers of a product. Common products may have a higher number of adverse events due to the higher total number of people using the product. openFDA, FDA

FDA adds: "There is no certainty that the reported event (adverse event or medication error) was actually due to the product. FDA does not require that a causal relationship between a product and event be proven, and reports do not always contain enough detail to properly evaluate an event." The information in these reports "cannot be used to estimate the incidence of these events."

Do not rely on openFDA to make decisions regarding medical care. While we make every effort to ensure that data is accurate, you should assume all results are unvalidated.

Not medical advice. This site counts what was reported to FDA. Questions about a medicine or device belong with a pharmacist or clinician.

270,928
reports across the class: 1.3% of all reports; 1,766
reports, 12 months to June 2026: 2,315 in the 12 months before; 96.3%
marked serious by the reporter: 57.4% across all reports; 8
drugs with a page: brand and generic names counted separately

Histamine-2 receptor antagonist is a pharmacologic class (an FDA Established Pharmacologic Class) with 8 drug pages on this site. Together those drugs are listed as a suspect or interacting product in 270,928 adverse event reports received by FDA, 1.3% of the database, from January 2004 to June 2026.

1,766 reports arrived in the 12 months to June 2026, down 24% from 2,315 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. 96.3% of the class's reports are marked serious, 7.1% record death among the outcomes and 3.6% record hospitalisation, as reported.

Across the class the reactions recorded most often are breast cancer (16.9%), prostate cancer (15.4%) and colorectal cancer (12.2%). The class median share shown beside each term is the middle value across the member drugs; it is the comparison used on every drug page in this class.

The members table is ordered by report count for navigation only. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."

Drugs in the class

Drug	Name type	Reports	Latest 12 months	Marked serious	Top term recorded
Ranitidine	generic	195,204	269	99.1%	Breast cancer
Ranitidine hydrochloride	generic	63,047	463	97.4%	Breast cancer
Famotidine	generic	6,009	687	64.6%	Drug ineffective
PepcidFamotidine	brand	2,589	122	42.7%	Drug ineffective
Pepcid CompleteFamotidine, calcium carbonate and magnesium hydroxide	brand	1,219	80	8.1%	Drug ineffective
Cimetidine	generic	1,121	40	84.5%	Drug ineffective
Pepcid ACFamotidine	brand	1,096	77	15.1%	Drug ineffective
Pepcid Ac Maximum StrengthFamotidine	brand	643	28	3.6%	Drug ineffective

Ordered by report count for navigation only. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."

Reports by month, five years

FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases.

Reactions recorded across the class

share of class reports recording the termmedian drug in the class

Breast cancerbreast cancer16.9%45,801
Prostate cancer15.4%41,788
Colorectal cancer12.2%33,010
Renal cancer11.3%30,621
Bladder cancer10.7%29,095
Oesophageal carcinoma6.2%16,872
Hepatic cancer5%13,511
Gastric cancer4.9%13,158
Pancreatic carcinoma4.5%12,218
Lung neoplasm malignantlung cancer4.4%12,003
Incorrect dose administeredthe wrong dose was given3.6%9,704
Neoplasm malignanta cancer, type not specified2.2%5,940
Drug ineffectivethe medicine did not work as expected1.7%4,510
Gastrointestinal carcinoma1.6%4,368
Thyroid cancer1.6%4,253
Injurya physical injury1.5%4,040
Skin cancerskin cancer1.3%3,632
Off label useused for a purpose or in a way not on the label1.2%3,144
Uterine cancer1.1%2,970
Painpain, site not specified1%2,685
Product use in unapproved indicationused for a purpose not on the label0.8%2,148
Ovarian cancer0.8%2,099
Fatiguetiredness0.7%1,891
Headachehead pain0.7%1,779
Nauseafeeling sick0.6%1,686

Solid bar: share of all class reports. Hollow bar: the median share across the 8 member drugs, the reference used on each member's page. One report can record several terms.

Outcomes, patients and reporters

Outcomes recorded

Death7.1%19,186

Life-threatening1.1%2,927

Hospitalisation (initial or prolonged)3.6%9,627

Disability0.9%2,568

Congenital anomaly0.5%1,479

Other serious92.9%251,619

Not serious3.7%9,929

Patient age

Under 20.2%448

2 to 110.3%698

12 to 170.2%503

18 to 445.8%15,607

45 to 6421.7%58,700

65 to 748.7%23,437

75 and over3.5%9,387

Age not given59.8%162,148

Who reported

Physician2.4%6,376

Pharmacist0.6%1,596

Other health professional3.2%8,600

Lawyer51%138,235

Consumer or non-health professional42.4%114,883

Not given0.5%1,238

Grey bar: all 20,646,523 reports in the database. Outcome flags are as the reporter set them and are not verified by FDA.

Questions about Histamine-2 receptor antagonist reports

Which drugs are in the Histamine-2 receptor antagonist class on this site?

Ranitidine, Ranitidine hydrochloride, Famotidine, Pepcid, Pepcid Complete and Cimetidine and 2 more. Class membership comes from the pharmacologic class (EPC) on the drug's FDA label.

How many reports does the class have?

270,928 reports through June 2026, 1,766 of them in the latest 12 months. A report listing two drugs of the class counts once for each.

What reactions are recorded most often?

breast cancer (16.9%), prostate cancer (15.4%), colorectal cancer (12.2%), renal cancer (11.3%) and bladder cancer (10.7%).

Can the members table be used to rank the drugs?

No. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic." Drugs differ in how many people take them, in the conditions they treat, in time on the market and in how diligently reports are collected.

How do I report an adverse event?

Through FDA MedWatch (Form FDA 3500, or 1-800-FDA-1088) or to the manufacturer. See the guide on how to report.

Where this comes from. Counts are built from the openFDA Drug Adverse Event (FAERS) bulk export released 28 Sep 2026, which holds reports FDA received through 30 Jun 2026. Drug names are as reported, resolved to the brand or generic name on the FDA label where openFDA's harmonisation matched them; classes are the pharmacologic class (EPC) from the label and the National Drug Code Directory of 17 Sep 2026. A class is the Established Pharmacologic Class most often attached to a drug's reports by openFDA's label harmonisation, or from the NDC Directory where reports carry none. No report narrative, lot number, patient detail or reporter identity is published. See the methodology and sources; FDA's record is authoritative, and corrections are handled within five working days.

Drug data (FAERS) through 30 Jun 2026; device data (MAUDE) through 31 Aug 2026. Not medical advice.