Drugs In Hypertension


Categories: Uncategorized
Sources: Disturbances Of The Heart

The drugs that are mostly used to lower blood pressure are nitrites

or drugs which are like nitrites, and these are nitroglycerin,

sodium nitrite, erythroltetra nitrate and amyl nitrite, and the

frequency of their use is in the order named. Other drugs used to

lower blood pressure are iodids, thyroid, alkalies, chloral, bromids

and aconite, the latter rarely.



Amyl nitrite is required only when a sudden immediate effect is

desired in angina pectoris or in some other serious spasmodic

condition. Sodium nitrite is more likely to upset the stomach than

is nitroglycerin. It acts, however, a little longer, but not enough

to warrant its frequent selection. The dose of sodium nitrite is

from 0.03 to 0.06 gm. (1/2 grain to a grain), best in tablet form

and given with plenty of water. The tablet should of course be

dissolved or crushed with the teeth. It should not be given on an

empty stomach, as it may cause considerable irritation and pain. It

more or less actively lowers the blood pressure for about an hour.



Erythrol tetranitrate is preferred by some clinicians who find that

its effect lasts somewhat longer. There is probably, however, no

better nitrite or nitrate than nitroglycerin. While it acts but a

short time, it acts effectively, and although no nitrite has

vasodilating effects for any length of time from one dose, when the

doses are given repeatedly and for days at a time, the blood

pressure will generally be more or less reduced. The dose is from

1/500 to 1/100 grain, three or four times a day, or every three

hours, as desired. The best form in which to use it is in a very

soluble tablet, and the tablet should not be dissolved unless

intense immediate action is desired. It acts when absorbed from the

tongue almost as rapidly as when given hypodermically; it acts in

two or three minutes, and the blood pressure may drop from 20 to 30

mm. In experimental tests the action does not last more than from

fifteen minutes to half an hour, but clinically the effect of

repeated doses is much more satisfactory. Spirit of glyceryl

trinitrate or spirit of Nitroglycerin, dose 1 minim, keeps well if

care is taken to guard against evaporation of alcohol; tablets if

well made and kept in bottles properly corked, will retain their

activity for months.



The closer a physician is to the laboratory, the less he believes in

the value of nitroglycerin in hypertension. The nearer he is to

clinical work the more he believes in it. It is a fact that in some

instances, even with a dose as small as 1/200 grain of

nitroglycerin, three or four times in twenty-four hours, the blood

pressure will be lower, whatever the diet is and whatever the other

treatments are, than if the patient does not take the nitroglycerin.

Also the value of these short relaxation periods from the standpoint

of a strained and tired heart should not be underestimated, the same

as the value of a night's rest, or the value of a recreation period

of an hour or two. If a patient has hypotension and a systolic

pressure of 110, and is given nitroglycerin, the very unpleasant

results from its administration will be immediately noticed. Hence

nitroglycerin is one of the most valuable drugs that we possess for

the treatment of hypertension, and some patients are even benefited

by as small a dose as l/500 grain. Lawrence [Footnote: Lawrence, C.

H.: The Effect of Pressure-Lowering Drugs and Therapeutic Measures

on Systolic and Diastolic Pressure in Man, Arch. Int. Med., April,

1912, p. 409.] found that the fall of diastolic pressure from

nitrites was about half of the fall of systolic pressure. When there

is no kidney lesion a very high systolic pressure falls more under

nitroglycerin than does a medium high systolic pressure.



Alkalies, whether potassium or sodium citrate or sodium bicarbonate,

are often of advantage in so changing and aiding metabolism, or

perhaps reducing the irritation from hyperacidity or a mild

condition of acidosis, that their administration causes a lowering

of blood pressure.



While iodids may not be direct vasodilators and do not render the

blood more aplastic or diminish its viscosity, as shown by Capps

[Footnote: Capps, J. A.: Effect of Iodids on the Circulation and

Blood Vessels in Arteriosclerosis, THE JOURNAL A. M. A., Oct. 12,

1912. p. 1350.] still, iodids in small doses, 0.1 to 0.2 gm. (1-1/2

to 3 grains) given from once to three times a day, after meals

(these small doses do not disturb the stomach), will stimulate the

thyroid gland to greater activity, and when this gland secretes

properly, the blood pressure is somewhat lowered. Of course, in

syphilitic sclerosis large doses of iodids are indicated and are

valuable.



In obese patients with hypertension, in the hypertension of women at

the menopause, and in hypertension with insufficient kidneys,

thyroid medication is often of great value. Sometimes a small dose

of from 0.1 to 0.2 gm. (1 1/12 to 3 grains) once a day is all that

is needed. At other times, especially when there is no marked

arteriosclerosis and no marked kidney or liver lesion, very high

blood pressures are reduced only by very large doses, even as much

as 10 grains a day. Such treatment is often of very great benefit.

Of course, if one of the persons under consideration has symptoms of

hyperthyroidism, or if small doses of thyroid cause palpitation, the

treatment is not indicated, on the one hand, and should be stopped,

on the other. Sometimes when the blood pressure cannot be reduced,

in these cases without apparent organic lesions, and thyroid

treatment is more or less successful, but at the same time causes

great excitation, it may be combined with bromid medication, and

then the benefit is sometimes very great.



A patient who cannot sleep and who has hypertension may receive

bromids if he is very irritable or if there are symptoms of thyroid

irritability; but the most successful sleep and lowering of blood

pressure is caused by chloral. A dose of 0.5 gm. (7 1/2 grains) at

night is generally sufficient and need not be long continued.

Chloral has been frequently given to reduce pressure in 0.2 to 0.25

gm. (3 or 4 grain) doses, three times a day, after meals.



Bromids, of course, will lower the blood pressure, but they depress

all metabolism, interfere with digestion, and are not advisable for

any length of time. However, in some cases they cause a marked

improvement in the patient's condition.



Patients under treatment with chloral, bromids, and thyroid

especially, should be carefully watched and the treatment modified

to meet the varying conditions. Patients under iodid need not be

seen so frequently; those under nitroglycerin or alkalies still less

frequently. But all patients under the active management of

hypertension should be seen at from one to three week intervals, and

the urine should be repeatedly examined and the blood pressure

carefully recorded.





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