Vasopressor effects

Untoward effects of both E and NE (usually to a lesser degree) are anxiety, headache, cerebral hemorrhage (from vasopressor effects), cardiac arrhythmias, especially in presence of digitaUs and certain anesthetic agents, and pulmonary edema as a result of pulmonary hypertension. The minimum subcutaneous lethal dose of E is about 4 mg, but recoveries have occurred after accidental overdosage with 16 mg subcutaneously and 30 mg intravenously, followed by immediate supportive treatment. 

Angiotensin II causes vasoconstriction by direct stimulation of ATj receptors on the vascular smooth muscle. It also enhances release of the neurotransmitter norepinephrine from the sympathetic nerve fibers present in the blood vessels. The vasopressor effects of Ag II may be inhibited pharmacologically in order to decrease TPR and treat hypertension. An important class of orally active drugs is the ACE inhibitors, including captopril and enalopril, which prevent formation of Ag II. More recently, angiotensin receptor antagonists have been developed that act at the vascular smooth muscle. These drugs, which include losartin and valsartan, are also orally active. 

Heart rate, ECG, blood pressure (when using for vasopressor effect)... 

WHO Special Programme of Research, Development and Research Training in Human Reproduction. The WHO multicentre trial of the vasopressor effects of combined oral contraceptives 1. Comparisons with IUD. Task Force on Oral Contraceptives. Contraception 1989 40(2) 129 15. 

Vasopressin [vay soe PRESS in] (antidiuretic hormone, ADH), is structurally related to oxytocin (Figure 25.5). The chemically-synthesized nonapeptide has replaced that extracted from animal posterior pituitaries. Vasopressin has both antidiuretic and vasopressor effects. In the kidney it binds to the V2 receptor to increase water permeability and resorption in the collecting tubules. Thus the major use of vasopressin is to treat diabetes insipidus. It also finds use in controlling bleeding due to esophageal varices or colonic diverticula. Other effects of vasopressin are mediated by the Vi receptor, found in vascular smooth muscle, liver and other tissues. As might be expected the major toxicity is water intoxication and hyponatremia. Headache, bronchoconstriction and tremor also can occur. Caution must be used in treating patients with coronary artery disease, epilepsy and asthma. 

Hydroxyzine may reverse the vasopressor effect of epinephrine patients requiring a vasopressor agent should use norepinephrine or metaraminol instead... 

Because tropicamide is reported to be devoid of vasopressor effects in adults, it is one of the safest mydriatic agents for use in patients with systemic hypertension, angina, or other cardiovascular disease. Tropicamide has also been shown to be the safest agent (as indexed by changes in blood pressure and heart rate) for dilated retinal examinations in neonates. Additional information on pupil dilation in infants may be foimd in Chapter 8. 

A-10. Many other nitrogenous compounds are formed in the intestine as a result of intestinal bacterial activity. Some have powerful pharmacological (vasopressor) effects. Intestinal bacteria convert lysine, arginine, tyrosine, ornithine and histidine to their vasopressor amines such as cadaverene, agmatine, tyramine, putrescine and histamine respectively. 

Nitric oxide (NO), a potent endogenous vasodilator, improved arterial oxygenation and reduced pulmonary artery pressures in patients with ARDS. However, it is also associated with hypotension, as well as being a mediator of sepsis-induced refractoriness to the vasopressor effects of catecholamines. Additional work is needed to define any role for NO and ketoconazole in the management of sepsis. 

Yes. Moderate doses result in vasopressor effect and an increase in heart rate and cardiac output. Large doses, or doses administered too quickly, rapidly increase blood pressure and stimulate baroreceptor reflexes. In this case, the drug may actually depress cardiac function and decrease heart rate and cardiac output. 

C. For predominantly vasopressor effects, infuse 10-20 mcg/kg/min and increase as needed. Doses above 50 mcg/kg/min may result in severe peripheral vasoconstriction and gangrene. 

The vasopressor effect of HORD is not centrally induced but by its stimulatoiy action on the heart muscle [45]. In isolated vas deferens of guinea pig, relative maximal response of HORD ethiodide was found to be higher (0.22) than tyramine (0.09) as compared to norepinephrine (1.00), which served as the reference [46]. HORD isolated from Phyllophora nervosa increased blood pressure, contracted nictating membrane when injected by i.v. route to cats. This epinephrine-like effect was less potent but more durable than epinephrine [5]. 

Alpha-Zbeta-agonists may have enhanced vasopressor effects. 

This experience indicated that indigo carmine not only has a vasopressor effect (SED VIII, p. 1070) but mi t be responsible for severe anaphylactic reactions in view of this, its further use should be discouraged. 

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