No such thing as normal

Neville Goodman

ANAESTHETISTS don't have many drugs. And those we have are steadily being taken away. We used to have an effective antiemetic — not that any antiemetic is really effective, but droperidol was the best we had. Maintenance doses for psychosis caused prolonged QT syndrome and it had to go. It was cheap and we anaesthetists used only a tiny dose once or twice per patient, so it was not worth making and we don't have it any more. We used to have methoxamine, an α-agonist useful for treating acute hypotension: gone —uneconomic. We replaced it with an alternative, metaraminol, but now that and another α-agonist, phenylephrine, are in short supply so we are urged to use them only when essential. Is that when the systolic blood pressure is 81 mmHg? Or should we wait until it's 79 mmHg?

I anaesthetised a chap the other day who was taking tralindopril. I'd never heard of it, though clearly it's an ACE inhibitor. I'd heard of captopril and enalapril; a lot of our renal patients are on perindopril; but there are 11 ACE inhibitors in the BNF. Eleven! We have difficulty getting hold of a simple cheap vasopressor that works, and there are 11 ACE inhibitors available to drop the blood pressure even further. The BNF makes no distinction between them: before listing each one, the advice refers generically to ‘ACE inhibitors’ or ‘an ACE inhibitor’. In a quick look at Medline for studies comparing ACE inhibitors one with another, the first two that turned up were for ACE inhibitors not (yet) in the BNF.

ACE inhibitors, according to the BNF, are second line to diuretics and ß-blockers, and I came across a Swedish study concluding that old drugs are just as good as new drugs at reducing the blood pressure in hypertension (there aren't enough data on long-term outcomes for many of the ACE inhibitors).

There are enough ACE inhibitors — we'll ignore all the other antihypertensives for the moment — and enough sub-groups (diabetics, diabetics with renal failure, patients who have already had a myocardial infarction, diabetics who have already had a myocardial infarction …) for controlled trials in hypertension to continue forever until complexity theory, the law of diminishing returns, or boredom stop them. And with a blood pressure of 120/80 now described as ‘pre-hypertension’ (just as skin is now described as ‘pre-melanoma’: see www.gruntdoc.com) there will soon be a cool ACE inhibitor for the yoof market, pre-packaged with ecstasy.