Bayer's Adalat XL product and Mylan's nifedipine extended release 60 mg not bioequivalent: Study

May 25 2010

Letter to the editor published in International Journal of Clinical Pharmacology and Therapeutics

Bayer Inc. today responded to Professor Marvin Meyer's letter to the editor, entitled: "Critical questions concerning the validity of the Bayer study report of differences in bioavailability between 60 mg of nifedipine osmotic push-pull systems after fasted and fed administration" and published in the online edition of the International Journal of Clinical Pharmacology and Therapeutics. Bayer responded to the clinical relevance of the differences in formulation and dissolution behaviour and the delayed absorption of Mylan's extended release nifedipine. Bayer supports the findings of the study, published in the February issue (Vol. 48 - No. 2/2010) of the International Journal of Clinical Pharmacology and Therapeutics, which demonstrate that the extended release generic nifedipine product is not bioequivalent to Adalat(R) XL(R) (nifedipine extended release tablets).

"Patient safety is Bayer Inc.'s top priority", said Dr. Shurjeel Choudhri, Head, Medical and Scientific Affairs, Bayer Inc. "We strongly encourage health care providers to monitor their patients who switch to the generic nifedipine product."

The Anschutz et al study shows that Bayer's nifedipine extended release 60 mg product and Mylan Nifedipine Extended Release 60 mg are not bioequivalent. Available safety and clinical data indicate that switching from Bayer's nifedipine 60 mg product to the generic product can lead to loss of efficacy and adverse events.

Adalat(R) XL(R), a clinically proven blood pressure control medication, delivers a relatively constant plasma level of nifedipine over 24 hours. This helps patients maintain a stable blood pressure level while avoiding unwanted side effects that may be seen with shorter acting agents. The generic nifedipine is also a time-release delivery product, but the study clearly demonstrated the existence of a lag time and reduced total nifedipine release. Safety and clinical data indicate that switching from Adalat(R) XL(R) 60 mg to the generic product can lead to loss of efficacy and adverse events.

Bayer has a longstanding commitment to the cardiovascular health of Canadians and will continue to actively market Adalat(R) XL(R).

To view the online version of the International Journal of Clinical Pharmacology and Therapeutics, visit: http://www.dustri.com/nc/journals-in-english/mag/int-journal-of-clinical-pharmacology-and-therapeutics.html.