Comparative effects of dihydroergotamine and hydergin on the blood flow, capillary filtration rate and the capacitance vessels in the human calf studied by plethysmography

Combination dihydroergotamine mesylate and heparin sodium with lidocaine HCl. Pharmacokinetics, mechanism of action, clinical efficacy, and adverse effects

Dihydroergotamine(DHE)-heparin combination offers a unique treatment modality for the prevention of deep vein thrombosis. The combination appears to affect all 3 limbs of Virchow's triad: hypercoagulability, venous stasis, and endothelial damage. In most efficacy studies, data indicated that the combination of DHE 0.5 mg and heparin 5000 IU was superior to low-dose heparin alone. Even when the efficacy of DHE-heparin was the same as that of heparin alone, the use of the combination allowed for a decrease in the heparin dose required.

Dihydroergotoxine, an ergot alkaloid without marked hypotensive effect, improves blood flow and metabolism in the underperfused canine myocardium

Regional myocardial blood flow was assessed in 6 anaesthetized dogs using radiolabelled microspheres. Lactate, H+, and O2 content were measured in arterial and local venous blood, obtained from the area supplied by the circumflex branch of the left coronary artery (LCX). Constriction of LCX by 67% led to considerable hemodynamic changes indicative of depressed global myocardial function. A significant release of lactate from the underperfused part of the left ventricle was recorded. Infusion of 0.7 micrograms/kg dihydroergotoxine over a period of 5 min induced a decrease in heart rate, left ventricular dp/dt max, and cardiac output, a sustained increase in total peripheral and femoral resistance and a transient increase in mean arterial blood pressure. Dihydroergotoxine markedly reduced lactate release and even, in some cases, induced lactate uptake and led to a significant increase in the endocardial blood flow both in the underperfused and normally perfused left ventricle. It is concluded that dihydroergotoxine, due to its ability to reduce myocardial oxygen demand and owing to its alpha-sympatholytic activity, which is not accompanied by any marked decrease in arterial blood pressure, causes improvement in blood flow in the underperfused myocardium and a marked amelioration of the impaired metabolic processes.

Alpha-adrenoceptors, 5-hydroxytryptamine receptors and the action of dihydroergotamine in human venous preparations obtained during saphenectomy procedures for varicose veins

Changes in tension were monitored isometrically on spiral strips from human saphenous veins obtained during surgical removal of varicose veins. Concentration-response curves for noradrenaline and 5-hydroxytryptamine (5-HT) were established by cumulative administrations, curves for dihydroergotamine were constructed from the mean responses to single concentrations. The use of the antagonists prazosin, yohimbine and pizotifen provided evidence for the existence of both postjunctional alpha 1- and alpha 2-adrenoceptors and for the existence of 5-HT receptors. The venoconstrictor effects of dihydroergotamine were unchanged by prazosin. Yohimbine antagonized both dihydroergotamine and 5-HT at about 60 times higher concentrations than required against noradrenaline whereas pizotifen inhibited responses to both dihydroergotamine and 5-HT at about 100 times lower concentrations than those to noradrenaline. These new results are in contrast to conclusions drawn from animal studies and do not support the suggestion that in man the venoconstrictor activity of dihydroergotamine is mediated through stimulation of alpha-adrenoceptors. The present results strongly suggest that in human saphenous veins the constrictor activity of dihydroergotamine is mediated at least in part through stimulation of 5-HT receptors.

The recording of venous compliance in the conscious dog: a method for the assessment of venoconstrictor agents

Determinations of drug-induced changes in venous compliance were performed in conscious dogs using a linear variable differential transformer. Changes in the diameter of the canine saphenous vein, produced by inflation to 45 mmHg of a sphygmomanometer cuff placed on the upper hind leg, were recorded. The cuff was inflated at 5-min intervals for 2 min before and after drug administration. Validation studies of this new method were performed by investigating the venoconstrictor activity of dihydroergotamine (Dihydergot). The intravenous administration of DHE, either locally or systemically, elicited dose-dependent and longlasting venoconstrictor responses with extremely small interindividual variations. Comparison of the present results to those reported for man suggests that recording of venous compliance in the conscious dog provides data with good predictability.

Pharmacological actions of the main metabolites of dihydroergotamine

Dihydroergotamine (DHE) and 5 of its main metabolites, namely 8'-hydroxy-dihydroergotamine (8'-OH-DHE), 8',10'-dihydroxy-dihydroergotamine (8',10'-OH-DHE), 2,3seco,N(1)formyl,3-keto,8'-hydroxy-dihydroergotamine (8'-OH,N(1)formyl-DHE), dihydrolysergic acid amide (DH-LSA) and dihydrolysergic acid (DH-LS) were investigated on human and canine veins in vitro, on canine veins in situ, and in the ganglion-blocked rat in vivo. Like DHE, the metabolites 8'-OH-DHE, 8', 10'-OH-DHE and DH-LSA caused constriction of human varicose veins and only weak alpha-adrenoceptor blockade. On canine femoral vein strips the same compounds produced predominantly alpha-adrenoceptor blockade and only negligible stimulation. 8'-OH,N(1)formyl-DHE and DH-LS were largely inactive. The same compounds, which were agonists on human vein strips in vitro, induced dose-dependent reduction of venous compliance when infused locally into the dog saphenous vein in situ. In the ganglion-blocked rat, only 8'-OH-DHE and 8',10'-OH-DHE besides the parent drug produced an increase in diastolic blood pressure when injected intravenously. It is concluded that DHE metabolites with considerable venoconstrictor activity may contribute to the selective therapeutic action of DHE.

The role of the prostanoid system in mediating the haemodynamic effects of dihydroergotamine

Dihydroergotamine (DHE) increases tonus in veins, especially in capacitance vessels, thereby reducing blood pooling and increasing venous blood flow velocity and it has been suggested that DHE achieves its effect partially through its influence on prostanoids synthesis and release. Pretreatment with indomethacin did not affect DHE response in central haemodynamic variables or in tissue blood flow in dogs; nor did it affect the reduced venous vessel area, increased blood flow in dogs; nor did it affect the reduced venous vessel area, increased venous blood flow velocity (measured ultrasonically), or reduced resting calf volume blood flow (measured by plethysmography), caused by DHE in humans. Although the number of animals and of humans in this study were small, nontheless it seems unlikely that the effect of clinically relevant doses of DHE is appreciably mediated by the prostanoid system.

Actions of co-dergocrine mesylate and its components at vascular smooth muscle

The mechanisms by which co-dergocrine mesylate (CODE) and its components modify vascular tone was investigated in vitro. Changes in tension were monitored isometrically on spiral strips of canine basilar arteries and femoral veins suspended in 10 ml organ baths and on spiral strips of canine saphenous veins superfused between two platinum electrodes for electric stimulation (150 mA, 0.1 ms, 2 Hz) and measurement of tritium overflow. Cumulative concentration-response curves were established for 5-hydroxytryptamine (5-HT), noradrenaline (NA), dihydroergocornine (DHCO), dihydroergocristine (DHEC), dihydro-alpha-ergokryptine (DH alpha E), dihydro-beta-ergokryptine (DH beta E) and CODE. CODE and its single components were about equally potent in antagonizing responses to 5-HT on basilar arteries. On femoral veins DHEC antagonized responses to NA noncompetitively whereas the other components caused competitive antagonism against NA. Compared to CODE, DH alpha E and DH beta E, the alpha-blocking potency of both DHCO and DHEC was about 10 times weaker. All 5 ergot compounds were about equally potent in antagonizing contractile responses to electric stimulation of saphenous veins whereas the stimulation-induced overflow of labeled NA was inhibited in the following order of potency: CODE greater than or equal to DHCO greater than DH alpha E greater than DH beta E greater than DHEC. The 5 ergot compounds stimulated arterial and venous smooth muscle at slightly higher concentrations than necessary for antagonism of 5-HT or NA. Evidence is presented that the mechanism of the stimulant action on arteries differs from that on veins. It is suggested that the diversity of actions of CODE is the base for its therapeutic effectiveness in patients suffering from regional vascular disorders.

Iatrogenic ergot vasospastic angiitis. A case report

Hydergin, a preparation composed of equal components of dihydroergocristine, dihydroergocryptine and dihydroergocornine has been used as a peripheral vasodilator. We have presented a case report, with arteriographic confirmation, in which, this drug has produced symptoms and signs of Iatrogenic Ergot Vasospastic Angiitis, involving the rare site of right ring finger.