Action, Medical Uses, and Dosage. In sufficiently large doses it acts as an intense irritant to the cardiac ganglia, producing thereby irritability, hyperaesthesia, arythmia, spasm and neuralgia of the heart, and even carditis and pericarditis. According to E. M. Hale, M. D., it acts upon the circular cardiac fibers, whereas digitalis acts upon all the muscular fibers of the heart. The tincture, in large doses, produces gastric irritation, and also affects the brain, causing confusion of mind, hallucination, and slight delirium. In excessive doses, a quickened pulse, constrictive headache, or constrictive sensation in the chest, cardiac pain with palpitation, vertigo, dimness of sight, over-sensitiveness to noises, and a disposition to be sad or to imagine evil, are among its many nervous manifestations.
Melancholia often follows such action.
It is generally conceded, however, that the mental, cerebral, gastric, and other effects are secondary to and dependent largely upon the primary effects of the drug upon the heart. In medicinal doses, night-blooming cereus diminishes the frequency of the pulse, and increases the renal secretions, and is, therefore, sedative and diuretic. In such doses it does not appear to weaken the nervous system in the least. The special field for cactus is diseases of the heart , in which it exerts a very decided action, palliating or removing the symptoms, and frequently giving prompt relief. However, our Allopathic antagonists, who are generally skeptical regarding the virtues of plants which do not possess unusually powerful properties, consider cactus as a valuable agent in mitral regurgitation , due to valvular lesions.