New_Zealand_Listener_09_14_2019

20 LISTENER SEPTEMBER 14 2019

increase urination to get rid of extra

water and salt so there’s less fluid

volume and lower pressure in your

blood vessels – like a tap that’s not

fully turned on.

The problem in New Zealand, says

van der Merwe, is that the cilazapril-

hydrochlorothiazide combination has

only 12.5mg of the diuretic, and that’s

too little to be effective. Randomised

controlled trials internationally have

found that it is no better than cila-

zapril alone and the combination is

not commonly used elsewhere. Over-

seas, hypertension poly-pills contain

up to 25mg of the diuretic. “It dates

back to whenever Pharmac was first

negotiating a package to get an ACE

inhibitor, and New Zealand just got

stuck with this,” says van der Merwe.

When patients’ blood pressure is not well

controlled with that combination, they

often end up on two, three or four pills,

when the best solution would be a com-

bination pill with double the dose of the

diuretic, which is not available here. Also

not available here are amiloride tablets. Ami-

loride is a potassium-sparing diuretic, but

Pharmac funds the tablets only in excep-

tional circumstances, forcing patients to take

the only alternative, a fluid that comes in

25ml bottles. “If you’re prescribed 10ml a

day, you end up with all these bottles in

your fridge, and if you’re going overseas

it’s a nightmare,” says van der Merwe. He

has put in numerous exceptional-circum-

stances applications, which have all been

declined. Pharmac has said it’s unable to

find a reliable supplier of the tablets, “but

that’s just nonsense”.

Phamac told the Listener its sole supplier

discontinued the product last year and it

was seeking alternative suppliers. It did

not answer questions about the strength

of the diuretic used in combination with

cilazapril, but said the agency funded 40

different drugs for hypertension and “does

not mandate which medicines are used

for which patients under which clinical

circumstances. This is a matter for prescrib-

ers, with due diligence and professionalism

as health professionals.”

Van der Merwe takes issue with the

recommended approach of total cardiovas-

cular risk when doctors assess the need for

a patient to start anti-hypertension treat-

ment. For example, a 50-year-old woman

with a blood pressure of 158/95 wouldn’t

be treated under current guidelines if she

had no other risk factors, such as being a

diabetic, smoker or having high cholesterol.

The recommended level at which treatment

of hypertension should begin regardless

of total cardiovascular risk is

repeated measurements in the

doctor’s office of 160/100. “Her

five-year risk of a heart attack or

stroke is just 1.7%, and if the risk

is under 5%, the benefits of treat-

ment are said to be outweighed

by the possible risk.” But van

der Merwe says a five-year risk

is meaningless. “A 50-year-old

woman now wants and expects

to live to her eighties or nineties

and to be fit and healthy for all

that time. With that blood pres-

sure, her lifetime risk is 50%, and

that’s what we should be looking

at.” He says the long-term effect

of even moderately raised blood

pressure can be severe.

THE STAKES ARE HIGH

That’s something Auckland car-

rental reservation agent and

part-time actor and singer Hugh

Boyd has discovered to his cost. Boyd, 67,

had hypertension for about eight years

before he finally agreed to start taking

medication in 2015. “The doctor would

talk to me about it and monitor it and say

we should do something about it and I

sometimes tried to ignore it. But it’s not

until you realise it’s a silent killer that you

do anything. I didn’t want to go on pills –

you read about the side effects and I’d had

an allergy reaction to other drugs before.

But I don’t think I really understood at the

start what [hypertension] can do to you.”

In January last year, Boyd was admitted

to North Shore Hospital with unstable

angina and ended up getting two stents

in his coronary arteries. “Knowing what I

know now, I wouldn’t have delayed.” He’s

now on five drugs – a statin, aspirin, an

D ACE inhibitor, a calcium channel blocker
O

N
N
A
C

H
IS

H

O
LM

HYPERTENSION

In 95% of cases,

doctors don’t know

the primary cause

of hypertension.

Wrong drugs to treat hypertension:

left, Dr Walter van der Merwe;

below, Hugh Boyd.

“A lot of people in New

Zealand start [blood

pressure] treatment

only once they’ve had a

heart attack or stroke,

which is putting the cart

before the horse.”