NEW YORK - George Rieveschl, a chemical engineer whom millions of sufferers of allergies, colds, rashes, hives, and hay fever can thank for the relief they receive by swallowing a capsule of beta-dimethylaminoethylbenzhydryl ether hydrochloride - the antihistamine he invented and renamed Benadryl - died Thursday in Cincinnati. He was 91 and lived in Covington, Ky.
The cause was pneumonia, his wife, Ellen, said.
Dr. Rieveschl (pronounced REE-va-shell), who had a doctorate in chemistry, was an assistant professor researching muscle-relaxing drugs at the University of Cincinnati in the early 1940s when he realized the powerful potential of that 19-syllable antihistamine compound, then being tested as a muscle relaxer.
Histamines are chemicals made in some cells that can damage the tiny blood vessels called capillaries, allowing blood plasma to leak into body tissues and cause swelling, itching, and redness. Antihistamines are manufactured compounds that block receptors in the capillaries, preventing those irritating, sometimes fatal effects.
The compound that Dr. Rieveschl synthesized was not the first antihistamine. A Swiss-born Italian pharmacologist, Daniel Bovet, had created a compound called neoantergan and, in 1957, received a Nobel Prize for his pioneering work. But neoantergan causes severe drowsiness.
"What George Rieveschl did was synthesize a compound that is much more tolerable, because it causes much less drowsiness," said I. Leonard Bernstein, a professor of medicine at the University of Cincinnati and a former president of the American Academy of Allergy, Asthma, and Immunology." It's a very benign drug that most people can tolerate."
The discovery of Benadryl was also significant because it was the first finding that specific receptors in capillaries can be affected by different compounds. "So there are now a whole series of antihistamines that will counter these different histamine receptors," Bernstein said.
It was also a profitable one. In 1943, Dr. Rieveschl left the University of Cincinnati to test his discovery at the laboratories of Parke-Davis, then the nation's largest drug manufacturer. Parke-Davis, now a subsidiary of
Because he had invented the drug before he worked for the company, Dr. Rieveschl received a 5 percent royalty for the 17-year length of the patent. Based on sales that rose to about $6 million a year by the early 1960s, that proved quite lucrative for him, Dr. Rieveschl told The Cincinnati Post in 1999. However, he said, he did not benefit from the huge profits Parke-Davis made after the Food and Drug Administration allowed Benadryl to become an over-the-counter drug in the 1980s. Sales then jumped to more than $180 million a year.
Officials at Pfizer did not respond Friday to requests for current information on Benadryl's profits or market share.
"He did this on his own, in the days before we had research teams," Bernstein added. "He understood this concept because he was a good organic chemist."
Born Jan. 9, 1916, in Lockland, Ohio, Dr. Rieveschl was the son of George and Alma Hoffling Rieveschl.
Dr. Rieveschl did not originally intend to be a chemist. In 1933 he graduated from the Ohio Mechanics Institute of Technology and began looking for work in commercial art. More than 200 job applications received six responses, all rejections. He turned his attention to chemistry and, paying tuition of $35 a semester, enrolled at the University of Cincinnati. There, he earned a bachelor's degree in 1937, a master's in 1939, and a doctorate in 1940.
Three years later, Dr. Rieveschl went to work at Parke-Davis, eventually rising to vice president of commercial development.
In 1970, he returned to his alma mater as vice president of research. He retired in 1982, and five years later the university's main science and engineering building was named in his honor.
He leaves two sons, five grandchildren, and four great-grandchildren.