ACONITUM — ACONITE 91 



2. Stimulating the inhibitory mechanism of the heart. The 

 vagus mechanism may be stimulated directly (digitalis, aconite, vera- 

 trum), or indirectly by stimulating the vagus center through an 

 increase of blood pressure (adrenaline). 



Blood pressure may be lowered by : 



1. Decreasing the output of the heart per unit of time (cardiac 

 depressants and vagal stimulants). 



2. Decreasing the amount of fluid in the veins (venesection). 



3. Decreasing the resistance in the peripheral vessels (vaso dila- 

 tors and purgatives). 



A large majority of drugs, in large doses, depress or weaken the 

 heart by direct action upon the cardiac muscle, but only those acting 

 through the vagus mechanism are of any therapeutic value for this 

 purpose. Drugs acting upon this mechanism slow the heart and in 

 this manner lower blood pressure, so that they are particularly ser- 

 viceable in cases of rapid heart with high tension, as in the asthenic 

 (mild) fevers, in the early stages of sthenic or long fevers, in acute 

 local inflammations, in valvular disease with excessive hypertrophy, 

 as in aneurism with high tension. In cases of rapid pulse with low 

 tension, drugs of the digitalis group are to be preferred. 



ACONITUM — ACONITE 



Synonyms. Wolfsbane, Monkshood 



Parts Used. The dried tuberous roots of Aconitum napellus, 

 and yielding, when assayed, not less than 0.5 per cent, of the ether 

 soluble alkaloids of aconite. 



Constituents. Aconite contains an alkaloid, aconitine, to which 

 its action is due together with aconine in minute amounts, which is 

 said to be a cardiac stimulant, benzoaconine, picroaconine and acon- 

 itic acid, which are inert. Aconitine is a crystalline alkaloid, 

 slightly soluble in water, but freely so in dilute acids or alcohol. 

 The amorphous aconitine of commerce is a mixture of alkaloids of 

 variable strength but much weaker than the crystalline variety. 

 Aconitine is the most toxic alkaloid known. 



Preparations and Doses. 



Fluidextractum Aconiti. H. ITt v — xv; 0.13 — 0.3. D. ni 



i/io— 1 ; 0.006—0.06. 

 Tinctura Aconiti. H. lU x— xxx; 0.6—2. D. 1TL %— 2; 



0.03—0.13. 

 Flemmings Tincture. H. TTt v — xv; 0.13 — 1. D. nx Vi — ■ 



1 ; 0.0016—0.06. 

 Aconitine U. 8. P. Crystalline. H. gr. V^o—Vs; 0.002— 



0.012. D. gr. yeoo— y25o ; 0.00011—0.00025. 



