Withdrawal of High Blood Pressure Medication

Monday 2 December 2002 12:00AM (view full episode)

An Australian study concluded that age, blood pressure control and the number of anti-hypertensive drugs are important factors in the clinical decision to withdraw drug treatment for high blood pressure.


Norman Swan: Welcome to the program.

Today: giving up your blood pressure pills; is it possible, and if so how?

Having your appendix out: surprising benefits for some people's innards;

And a new way of identifying whether infections are the causes of more diseases than we ever imagined.

Almost 3-million Australians over the age of 25 are thought to have high blood pressure, hypertension, in the jargon. For those who can't get it down by exercising, losing weight and cutting back on salt, medication is needed to help to prevent heart attacks and strokes.

But even with new drugs on the market which don't have many side effects, no-one likes the thought of medication for life, which is usually what you're told.

So can you ever get off your blood pressuring lowering tablets?

Well according to work done in Melbourne, the answer is yes, but only for some people.

The findings came from a large study of anti-hypertensive treatment in the elderly; but the discovery was almost by accident when one of the researchers, Dr Mark Nelson, noticed a curious thing.

Mark Nelson: In fact I called this the John West study, because we accepted the patients that the main study rejected. About two-thirds of the patients who came in were currently on anti-hypertensive medication, so we had to wash them out of those medications to prove that they were hypertensive, so that they could go into the study. And about 17%, no matter how long we seemed to wait, never went back up.

Norman Swan: So either they were misdiagnosed in the first place, or they'd been cured.

Mark Nelson: There's a number of possibilities. There is misdiagnosis, there's a phenomenon called white coat hypertension, which means that somebody, when they're getting their blood pressure checked by their doctor, has a higher level than they do when they're walking around in the street. It is possible that they were simply commenced on medication with incorrect diagnoses, and as you're saying, there is a possibility of cure.

Norman Swan: Mark Nelson then decided to tack on an extra study to the big one. He wanted to find out what it was about the people, this 17%, which allowed them to stay off their tablets. Because you've got to be careful. The price of not treating high blood pressure can be your life.

Mark followed 500 people with a diagnosis of hypertension who were attending general practitioners in Victoria.

Mark Nelson: The 17% that we saw in the general group was actually higher in this group when we found that we could successfully take a much larger percentage of their medication and that they would be still with blood pressure in the normal blood pressure range 12 months later.

Norman Swan: And how high have their blood pressures been at the beginning and how long have they been treated before you took them off?

Mark Nelson: We had access to the general practitioners' records, but we could only find the records for about 40% of the subjects. So we couldn't investigate that. All we could investigate were what the patients were currently presenting with, and this perhaps represents what actually happens in clinical practice. I was interested in looking at what I called desk-top indicators, that is, simple things that the average general practitioner sitting there with their patient can find by either measuring it on the patient, or looking in their medical record.

Norman Swan: And these 500 people you studied, what happened with them?

Mark Nelson: About 38% of them remained normotensive, 12 months after they'd stopped their medication, normotensive being normal blood pressure. Amongst those who were normotensive at 12 months, it was much more common amongst younger patients. When I'm talking about younger patients, I'm talking about the younger old, which is 65 to 74 year olds. Patients who had lower on treatment systolic blood pressure; systolic blood pressure is the higher blood pressure: the high one is the systolic, the lower one is the diastolic. And also patients on a single agent which is not very surprising. Obviously if you've got lower blood pressure, it's easier to control.

Norman Swan: So they tended to be people who were more successfully treated and treated with just one drug, therefore the doctor wasn't having too much trouble getting the blood pressure down.

Mark Nelson: That's right. It probably was an indicator of their pre-treatment blood pressure. There was one other factor that did predict success in remaining normotensive, that was patients with a greater waist-hip ratio, and what that represents, if you like, is central obesity.

Norman Swan: Central obesity predicted staying off drugs?

Mark Nelson: It did, and that was a surprise to us. There is biological feasibility I think, because I have previously done a meta-analysis of other studies that have looked at anti-hypertensive blood pressure withdrawal.

Norman Swan: A meta-analysis is where you study the other scientific literature and try and bring together the figures to make sense of them.

Mark Nelson: That's right, and two things that predicted maintenance of normal blood pressure after drug withdrawal were salt restriction and weight loss. So what I can assume may have happened here is that patients who greater waist-hip ratio had the opportunity of losing weight, and hence maintaining their normal blood pressure.

Norman Swan: So let's very briefly describe two or three situations in a general practitioner's surgery and what your study and others helps to inform. So somebody might be listening to this who has just been diagnosed with high blood pressure, the doctor wants to put you on blood pressure medication, you're over 65 and you say, 'Oh well, why don't I just wait for a year and it'll come down.' What's the answer?

Mark Nelson: In that case you're talking about initiation of blood pressure medication, then it's reasonable if the doctor has done repeated blood pressure measurements, two or three measurements at least a week apart, and they do show that there is hypertension, then the clinical trials support that person being offered initially behavioural modifications, so things such as exercise, weight loss, salt restriction, smoking cessation etc. usually, but not always, they would then require medication.

Norman Swan: The second question is, Well I've been on blood pressure medication now for a year, and my blood pressure is normal, Doctor can't I come off it now? What's the answer?

Mark Nelson: Any arrangement between the physician and a patient is unique. If that person has never had a stroke or a heart attack or doesn't have bad arteries in their legs, what is called secondary prevention if they are in those circumstances, they certainly can't come off their medication.

Norman Swan: And that's because just to say is that what seems to be normal blood pressure is actually high for them, it's significant risk factor because of everything else going on at the same time.

Mark Nelson: Exactly. It's what's called absolute risk, that is, your risk of having a heart attack of stroke, that delineates who best benefits from medication.

Norman Swan: But if you're otherwise healthy, and there's no risk of heart disease, what you're saying is that if you're on one drug, your blood pressure is not that high on treatment, it might be worth a trial stopping.

Mark Nelson: It may well be. But reinforcing the factors that I said before about behavioural modification is that we know that things like salt restriction, weight loss, exercise, bringing your blood pressure down, but if we move away from cardiovascular disease, those sorts of activities are beneficial to help generally. For example, cancer prevention. So I would ask the doctors to consider that, and I'm sure that they will have patients who are willing to accept behavioural modification in the circumstances where they could swap it for their medication.

Norman Swan: Dr Mark Nelson, who's an NH&MRC Fellow in the Department of Epidemiology and Preventive Medicine at Monash University in Melbourne.


Nelson M.R. et al. Predictors of normotension on withdrawal of antihypertensive drugs in elderly patients: prospective study in second Australian national blood pressure study cohort. British Medical Journal, Vol. 325, 12 October 2002, pp 815-817


Dr Mark Nelson
Department of Epidemiology and Preventive Medicine,
Monash University,
Alfred Hospital,
Prahran Vic. 3181


Dr Norman Swan
Brigitte Seega