In the same year, Ahmed Hegazy submitted his invention (in collaboration with Klaus-Dieter Rämsch) of an extended release, solid medicinal preparation of nifedipine to the German Patent Office in Munich, patenting the “use of nifedipine crystals with a specific surface area of 1-4 m2/g for the production of solid medicinal formulations for achieving long-lasting blood levels for the oral treatment of hypertension by administration 1 to 2 times”, an invention that became known as Adalat retard from Bayer (see letter Dr Schauerte). In that formulation, the active ingredient is released over a period of up to 36 hours. With the increasing incidence of heart disease in that period—heart failure became the first cause of death in West Germany—and the new  formulation, the medication replaced Aspirine in the 1990s as the biggest single product of Bayer. As Alexander Mey noted, "[d]iese Maßnahmen führten dazu, dass der Umsatz im Jahr 2000 auf 1,7 Mrd. US-$ stieg, obwohl das Präparat bereits ein Vierteljahrhundert am Markt war." On 14 October 1991, Hegazy was awarded the Otto Bayer Medal—no relation to the company founder—for his work solubilizing poorly soluble active ingredients such as nifedipine, a prize, that the Bayer Group has been using to honor excellent research since 1984. By 2020, 528 researchers had received the award. A 1995 US lawsuit, in which Hegazy defended his patent, found that Pfizers Procardia XL product was also based on his European patent No. 0047899, United States Patent 5264446.
No difference was found in the rate of deaths among babies around the time of birth, while data on longer-term outcomes is lacking. Other
Raynauds phenomenon is often treated with nifedipine. A 2005 meta-analysis showed modest benefits (33% decrease in attack severity, 2.8-5 reduction in absolute number of attacks per week); it does conclude that most included studies used low doses of nifedipine.Topical nifedipine has been shown to be as effective as topical nitrates for anal fissures.Nifedipine is also used in high-altitude medicine to treat high altitude pulmonary edema.Nifedipine is one of the main choices for the treatment of Prinzmetal angina due to its vasodilating effects on the coronary arteries.Other uses include painful spasms of the esophagus such as from cancer or tetanus. It is also used for the small subset of people with pulmonary hypertension.Finally, nifedipine can be used in the treatment of renal calculi, which are commonly referred to as kidney stones. Studies have indicated that it helps to relieve renal colic. However, alpha blockers (such as tamsulosin) have been described as being significantly better. Side effects
Nifedipine rapidly lowers blood pressure, and patients are commonly warned they may feel dizzy or faint after taking the first few doses. Tachycardia (fast heart rate) may occur as a reaction. These problems are much less frequent in the sustained-release preparations of nifedipine.Extended release formulations of nifedipine should be taken on an empty stomach, and patients are warned not to consume anything containing grapefruit or grapefruit juice, as they raise blood nifedipine levels.