FDA continues to investigate the presence of the N-Nitrosodimethylamine (NDMA) impurity in ranitidine and is now aware of NDMA in nizatidine, which is chemically similar to ranitidine. Both medicines are H2 blockers which decrease the amount of acid in the stomach. FDA has identified NDMA in ranitidine and nizatidine active pharmaceutical ingredient (API) and finished drugs.

FDA is posting its laboratory results in the table below showing NDMA levels in all ranitidine and nizatidine samples it tested, including API and finished drug which included tablets and syrup. NDMA was present in all samples tested. Testing of ranitidine for injection is still ongoing.

For reference, consuming up to 0.096 micrograms or 0.32 parts per million (ppm) of NDMA per day is considered reasonably safe for human ingestion based on lifetime exposure. FDA has set the acceptable daily intake limit for NDMA at 0.096 micrograms or 0.32 ppm for ranitidine. Although many manufacturers have already recalled ranitidine voluntarily, FDA will recommend recalls to manufacturers with NDMA levels above the acceptable daily intake limit.

The methods FDA used in the laboratory testing are available here.

FDA also developed a simulated gastric fluid (SGF) model to be used with the LC-MS testing method to estimate the biological significance of in vitro findings. The SGF and simulated intestinal fluid (SIF) models are intended to detect the formation of NDMA in systems that approximate the stomach and intestinal fluids, respectively. The results of these tests showed no additional NDMA generated in the stomach.

FDA has determined that the levels of NDMA in ranitidine and nizatidine are similar to the levels you would expect to be exposed to if you ate common foods like grilled or smoked meats.


Company Product Lots Tested NDMA level ppm NDMA level (micrograms-mcg/tablet or oral dose)
Sanofi Pharmaceutical OTC Ranitidine 150mg 19E413M, 19D554, 19A432U, 19C540, 19D431I, 19D442N, 19D423M, 19D464M, 0.07-2.38 0.01-0.36
Sanofi Pharmaceutical OTC Ranitidine 75mg 18L012U, 9A003U, 19B006M, 18M025M, 18N023U, 19B005N, 19A002U, 18N026U 0.10-0.55 0.01-0.04
Cardinal Health OTC Ranitidine 150mg 9FE2953 1.02 0.15
Watson Rx Nizatidine 150mg 1350798M 0.05 0.01
Watson Rx Nizatidine 300mg 1333973A 0.04 0.01
Strides Shasun Ltd Rx Nizatidine 150mg 7704758A 0.11 0.02
Strides Shasun Ltd Rx Nizatidine 300mg 7704022A 0.09 0.03
Novitium Rx Ranitidine 300mg S18038B 2.85 0.86
Dr Reddy’s Rx Ranitidine 300mg C805265 0.68 0.20
Strides Shasun Ltd Rx Ranitidine 300mg 7702255A 0.11 0.03
Sandoz Rx Ranitidine 300mg HU2207 0.82 0.25
Strides Shasun Ltd Rx Ranitidine 300mg 7704537A 0.02 0.00
Aurobindo Rx Ranitidine 300mg RA3019001-A 1.86 0.56
Ajanta Pharma USA Inc Rx Ranitidine 300mg PA1229B 0.23 0.07
Silarx Pharma Ranitidine 150mg Syrup 3652081-02661 1.37 0.20
Pharma Associates Ranitidine 150mg Syrup BE00, BF75, BF77, BF78, BDFF, COAC 0.03-0.07 0.004-0.012
Amneal Pharmaceuticals Ranitidine 300mg AR181795A, AR190878A, AR190876A, AR191177A, HB05819, HB06119, HL08718 0.52-2.17 0.16-0.65
Sanofi Pharmaceutical Ranitidine 150mg 19D570, 19D428U, 19E408M 0.08-2.17 0.01-0.33


Source: FDA