1950s – Blood-pressure medications arrive on the U.S. market.

1980s – Drug makers begin to promote calcium channel blockers for hypertension, while downplaying the older, safer, cheaper diuretics.

1982 to 1992 – Diuretic use declines from 56 percent to 27 percent of patients with high blood pressure.

1992 – The Fifth Report of the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure identifies diuretics and beta blockers as preferred drugs for uncomplicated hypertension.

1996 – Calcium channel blockers are the most heavily advertised drugs in The New England Journal of Medicine this year. There are no ads in the journal for diuretics.

1997 – The Joint National Committee redefines hypertension at a lower blood pressure, 140/90.

January 1998 – A study, published in The New England Journal of Medicine, reviewed 70 medical-journal articles that discussed the safety of calcium channel blockers and found that 96 percent of the authors who supported the drugs had financial relationships with the drugs' makers, as opposed to 37 percent of the authors who were critical.

September 1998 – A WHO task force and other experts agree to guidelines saying any anti-hypertensive drug could be used as a first treatment. WHO announces that half-a-billion people worldwide need hypertension treatment.

November 1998 – WHO founds the Initiative for Cardiovascular Health Research in the Developing Countries.

February 1999 – WHO task force presents recommendations for primary-physician care of mild hypertension, backed by studies funded by Bayer and AstraZeneca. Defining hypertension as over 140/90, “normal” as 130/85 and “optimal” as 120/80, the recommendations would classify 45 percent of people of all ages, and nearly 60 percent of elderly people, as hypertensive. Hundreds of doctors object.

August 2000 – A study reported to the European Cardiology Society shows the use of calcium channel blockers led each year to nearly 85,000 avoidable heart attacks and heart failures worldwide, with half the cases in the United States.

2002 to present – Drug industry accelerates campaigns to get more people to check their blood pressure and to get patients to take more than one drug for hypertension, combining a diuretic with newer drugs.

May 2003 – A new U.S. guideline says 45 million Americans have “prehypertension,” defined as systolic pressure from 120 to 139, or diastolic from 80 to 89. It also recommends that doctors add one or more different blood-pressure drugs if diuretics did not lower patients' blood pressure below 140/90.