Epinephrine pharmacological effects

While epinephrine is usually well tolerated in young and healthy individuals, there may be problems in elderly patients with cardiac arrhythmia or previous myocardial infarction episodes [31-33]. Pharmacological effects of epinephrine include rapid rise in blood pressure, pallor, anxiety, tachycardia, headache and tremor as well as vertigo. Most commonly these effects occur after intravenous injection or after overdosing epinephrine. Cardiac arrhythmia or pulmonary edema may develop in serious cases [33, 34]. 

Epinephrine is widely used in clinical medicine for its multiple pharmacologic effects particularly for its potent vasoconstrictor effects. For example, in a dilute solution of 1 100,000, it provides a surgical tourniquet and facilitates a blood-free operating field. It is administered by nebulizer and face mask for post-intubation croup and for viral croup. 

Epinephrine has a narrow benefit-to-risk ratio. Along with its therapeutic effects, when administered in recommended doses by any route, it potentially causes transient anxiety, fear, restlessness, palpitations, pallor, tremor, and headache. Although usually perceived as adverse effects, such symptoms indicate that a pharmacologically active dose of the medication has been absorbed. The desirable pharmacologic effects of epinephrine cannot be separated from the undesirable pharmacologic effects [10]. 

The L-isomers are the naturally occurring forms of epinephrine and norepinephrine and possess considerably greater pharmacological effects than do the D-isomers. Throughout most of the world, epinephrine and norepinephrine are known as adrenaline and noradrenaline, respectively. 

Phenylephrine is a synthetic sympathomimetic amine structurally similar to epinephrine. It acts primarily on ai receptors and has little or no effect on (3 receptors. A minor part of its pharmacologic effects may be attributed to release of norepinephrine from adrenergic nerve terminals. 

The toxicities of the beta blockers are directly related to their pharmacologic effects. These agents block the effects of catecholamines such as epinephrine and norepinephrine on the beta-1 and beta-2 receptors. Beta-1 receptors are located in the heart, kidneys, and eyes. Toxicity is most often due to antagonism of the cardiac beta-1 receptors. 

The pharmacological effects of lycorine (1) have been studied using the guinea pig it caused concentration-dependent relaxation of the isolated epinephrine-precontacted pulmonary artery. In this study, its effects on heart were suggested to be mediated by the stimulation of 8-adrenergic receptors 102). 

Bromelain has shown a wide variety of pharmacological effects in cliiucal, in vitro and in vivo studies. These effects include bum debridement, anti-inflammatory activity, prevention of epinephrine-induced pulmonary edema, smooth muscle relaxation, stimulation of muscle contractions, enhanced antibiotic absorption, immunomodulation, cancer prevention and remission, antitumor activity, ulcer prevention, sinusitis relief, appetite inhibition, shortening of labor, and enhanced excretion of fat. The precise nature of these effects (some of which are not produced by other proteases such as ficin, papain, and trypsin) is not clear. 

Both hormones are pyrocatechol (o-dihydroxybenzene) derivatives, which are easily oxidized. This fact explains the histochemical reaction of the chromaffin tissue. The hormonal content of the adrenal medulla is relatively high (several mg per gm of gland). The two active substances of the adrenal medulla, epinephrine and norepinephrine, are both derivatives of phenyl ethylamine, which possesses strong pharmacologic effects. 

The physiological effects of the catecholamines are mediated by a large number of different receptors that are of particular interest in pharmacology. Norepinephrine acts in the autonomic nervous system and certain areas of the brain. Epinephrine is also used as a transmitter by some neurons. 

The distinctive feature of a-adrenoblockers is their ability to reduce the pressor effect of pharmacological doses of epinephrine (adrenaline). 

Pharmacology Dipivefrin is a prodrug of epinephrine. Dipivefrin, converted to epinephrine in the eye by enzymatic hydrolysis, appears to act by decreasing aqueous production and enhancing outflow facility. It has the same therapeutic effects as epinephrine with fewer local and systemic side effects. 

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