Sympathomimetics, classification

MAO Is have not been evaluated systematically for treatment of PD under the current diagnostic classification and generally are reserved for patients who are refractory to other treatments.48,49 MAOIs have significant side effects that limit adherence. Additionally, patients must adhere to dietary restriction of tyramine and avoid sympathomimetic drugs to avoid hypertensive crisis. 

Classification of sympathomimetics by mode of action and selectivity for adrenoceptors... 

Amphetamine [XXII) is a central stimulant and many would not classify it with the antidepressant drugs proper. It has, however, been extensively used in the treatment of depression, it produces euphoria and some at least of its actions may be due to inhibition of monoamine oxidase. However, it also inhibits dopamine- S-oxidase, impairs the noradrenaline binding capacity of the brain and has direct sympathomimetic activity. Its classification with the antidepressants seems, therefore, to be justified, but it is not included with the monoamine oxidase inhibitors, since only a small part of its action can be attributed to enzyme inhibition. Amphetamine is a potentially addictive drug and it should be used cautiously and over short periods of time. Other compounds which are used, if at all, only for the treatment of mild depression, include methylphenidate [XXIII), pipradol [Table 5.2) and deanol (XXIV). The last named compound is interesting since it may owe its effectiveness to a stimulant action on acetylcholine synthesis > . ... 

CLASSIFICATION OF ADRENERGIC RECEPTORS Understanding the diverse effects of the catecholamines and sympathomimetic agents requires understanding the properties of the different types of adrenergic receptors and their distribution on various tissues and organs (Tables 6-1,... 

Understanding the pharmacological properties of sympathomimetics and their antagonists depends on knowledge of the classification, distribution, and mechanism of action of a and fi adrenergic receptors (see Tables 6-1, 6-6, 6-7, Figure 10-1, and Table 10-6). 

FIGURE 10-1 Classification of adrenergic receptor agonists and drugs that produce sympathomimetic effects. For... 

Classification The sympathomimetics are direct or indirect adrenoceptor agonists and are subdivided in two ways by mode of action and by spectrum of action (Figure 9-1). 

Health Canada s Natural Health Products Directorate (NHPD) has concluded that daily use by healthy adults of p-synephrine at up to 50 mg, or up to 40 mg in combination with up to 320 mg of caffeine, would generally result in a Type III risk classification. This classification is defined to mean that such use "is not likely to cause any adverse health consequences." On the other hand, NHPD determined that products that contain p-synephrine but lack certain cautionary statements, identified as "contraindicated in children, pregnancy, and breast-feeding, do not use if you are taking blood pressure medications (either hypertensives or antihypertensives), thyroid medications, sympathomimetics, or monoamine oxidase inhibitors," would be subject to a Type II risk classification (meaning "the use of, or exposure to, such a product may cause temporary adverse hedth consequences or where the probability of serious adverse health consequences is remote") (Maries 2011). 

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