The uses of the methonium compounds : the Bengué memorial award lecture, 1952 / by W.D.M. Paton.

  • William Paton
Date:
[1953?]
Catalogue details

Licence: In copyright

Credit: The uses of the methonium compounds : the Bengué memorial award lecture, 1952 / by W.D.M. Paton. Source: Wellcome Collection.

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    But there is no evidence yet that the fundamental processes involved can be reversed. If a patient with hypertension is taken off hexamethonium he almost always relapses to his previous state. If his kidneys have shown signs of damage already, treatment usually does not do much to improve them. It appears, there¬ fore, that though some of the incidental pathology may recover by the lowering of the blood pressure, so far as any renal damage has been done this is more or less irreversible. On the specific question of whether hexamethonium alters renal blood flow, there is still uncertainty, and it is only possible to say that sometimes it is depressed, less often increased, and sometimes unaffected. This is one of the important points that still needs settling. As to the third question, the main doubts were at first whether the fall of blood pressure might not bring a danger of cerebral thrombosis and of a dangerous reduction of the blood supply to the heart. As already mentioned, so far as the heart was concerned, it appears that the reduction of the load on it does a good deal of benefit, and signs of coronary ischaemia have been few. Similarly, although patients with hypertension are often liable to small transient cerebral episodes, these, in general, do not seem to become more common under treatment, and headaches, in particular, are almost always removed. It seems likely, therefore, that these dangers of fall in blood supply to vital organs are only slight, probably because there is normally some autonomic tone in their vessels, so that the action of hexamethonium in lowering the blood pressure is accompanied by a widening of the vessels to these areas, sufficient to maintain an adequate blood supply. One particular development needs special mention. It was soon found that patients receiving hexamethonium became tolerant to it and the dose required to produce a given fall in blood pressure steadily rose. It was almost always possible, by increasing the dose, to retain the therapeutic effect. This tolerance passes off when the drug is withdrawn and returns again when treatment is re-started. Little is known about the cause of this, but it probably represents an important clue to the pathological processes underlying hypertension. From what has been said it is obvious that treatment with hexamethonium is not a simple matter. Its main defects are :—(i) that in most patients the drug must be given subcutaneously several times a day so that the patient has to live a sort of “ diabetic ” regime ; (2) that the dose given to the patient has to be very carefully balanced under supervision in hospital to start with, and (3) that the patient has to get used to having the symptoms of partial ganglionic block of other functions. The advantages of treatment, however, particularly in the severe case, are considerable, sometimes even life-saving. There may be a substantial relief of symptoms and regression of the signs in the eyes and in the heart. The treat¬ ment is relatively safe, provided care is taken to adjust the dose carefully and to warn the patient about his sensitivity to posture. There have been very few “ toxic effects/' and the drug is cheap and easy to dispense.
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