Monoamine oxidase inhibitors examples

Serious adverse effects of epinephrine potentially occur when it is given in an excessive dose, or too rapidly, for example, as an intravenous bolus or a rapid intravenous infusion. These include ventricular dysrhythmias, angina, myocardial infarction, pulmonary edema, sudden sharp increase in blood pressure, and cerebral hemorrhage. The risk of epinephrine adverse effects is also potentially increased in patients with hypertension or ischemic heart disease, and in those using (3-blockers (due to unopposed epinephrine action on vascular Ui-adrenergic receptors), monoamine oxidase inhibitors, tricyclic antidepressants, or cocaine. Even in these patients, there is no absolute contraindication for the use of epinephrine in the treatment of anaphylaxis [1,5,6]. 

MAO (monoamine oxidase) inhibitor Non-selective inhibitors of the enzyme monoamine oxidase. An example is iproniazid, one of the first-generation anti-... 

Several different types of serotonin receptor (for example, S-HTi / 5-HT2A/ 5-HT2C/ 5-HTib/id) have been associated with the motor side effects of the SSRIs which may arise should these drugs be administered in conjunction with a monoamine oxidase inhibitor. The 5-HT3 receptor is an example of a non-selective cation charmel receptor which is permeable to both sodium and potassium ions and, because both calcium and magnesium ions can modulate its activity, the 5-HT3 receptor resembles the glutamate-NMDA receptor. Antagonists of the 5-HT3 receptor, such as ondansetron, are effective antiemetics and are particularly useful when... 

Serendipity has played a major role in the discovery of most classes of psychotropic drugs. For example, the observation that the first antidepressants, the tricyclic antidepressants and the monoamine oxidase inhibitors, impeded the reuptake of biogenic amines into brain slices, or inhibited their metabolism, following their acute administration to rats, provided the experimenter with a mechanism that could be easily investigated in vitro. Such methods led to the development of numerous antidepressants that differed in their potency, and to some extent in their side effects (for example, the selective serotonin reuptake inhibitors) but did little to further the development of novel antidepressants showing greater therapeutic efficacy. The accidental discovery of atypical antidepressants such as mianserin led to the broadening of the basis of the animal models... 

Examples of monoamine oxidase inhibitors are phenelzine, tranylcypromine, isocarboxazid and mo-clobemide. They are indicated for atypical depression. Changes in the neurotransmitter levels are seen in several days but the clinical effect may lag by several weeks. Phenelzine is a non-selective hydrazine-type monoamine oxidase inhibitor while the also non-selective inhibitor tranylcypromine is of the non-hydrazine-type. Phenelzine, tranylcypromine and isocarboxazid are irreversible inhibitors. Phenelzine is partly metabolized by acetylation and slow acetylators are more prone to toxicity. It has anxiolytic properties and superior efficiacy in treating severe anxiety. 

By contrast, a number of studies have not found verapamil monotherapy to be effective for acute mania (Table 10-14). Several case reports in the literature have not supported verapamil s potential antimanic properties. For example. Barton and Gitlin ( 262) found that none of eight acutely manic or hypomanic patients treated openly improved on verapamil. By contrast, there are several case reports of hypomania (some monoamine oxidase inhibitor—induced) improving with verapamil. Dubovsky (255) notes that, in his experience with spontaneous mania, he has been unimpressed with verapamil in patients who had previously been unresponsive to lithium. 

Synergism - a potentiation or prolongation which results in much greater than expected effects. This could involve competitive substrates for an enzyme or receptor, decreased excretion, displaced plasma protein binding, etc. The analgesic propoxyphene (Darvon ) slows down the excretion of ethanol and so increases the depressant effects of the alcohol. Recall the example given earlier of the monoamine oxidase inhibitors used as antidepressants and the tyramine-containing foods which could precipitate a hypertensive crisis. 

Strong support for the biogenic amine theory of depression is provided by the powerful antidepressant effect of inhibitors of monoamine oxidase. An example is pargyline (Fig. 30-33), which forms a covalent... 

The oxazolidinone-based compounds are the most common (Figure 23.1), and examples include antibacterial,27-28 adhesion receptor antagonists,29-30 tumor necrosis factor inhibitors,31 platelet aggregation inhibitors,32 antimigraine drugs,33 and monoamine oxidase inhibitors.3435 In one case, an oxazolidinone has been used as a transdermal drug delivery agent.36... 

SSRIs can provoke 5HT neurotoxicity (the 5HT syndrome) through pharmacodynamic interactions with other drugs that also potentiate 5HT function. Often the ability of the interacting drug to facilitate 5HT function is well known, as is the case, for example, when SSRIs are combined with monoamine oxidase inhibitors or lithium. In other cases, however, the potential 5HT activity of the co-administered drug is not widely known. The ability of the antibiotic linezolid to inhibit MAO and thereby to cause 5HT neurotoxicity in combination with SSRIs has been noted previously (SEDA-27, 14), and further cases have now been reported. 

The amphetamines should not be used together with or within 14 days of any monoamine oxidase inhibitors severe hypertensive reactions and on occasion confu-sional states (for example with fenfluramine) can occur (SED-9, 9). 

Action on receptors provides numerous examples. Beneficial interactions are sought in overdose, as with the use of naloxone for morphine overdose (opioid receptor), of atropine for anticholinesterase, i.e. insecticide poisoning (acetylcholine receptor), of isoproterelol (isoprenaline) for overdose with a P-adrenoceptor blocker (p-adrenoceptor), of phentolamine for the monoamine oxidase inhibitor-sympathomimetic interaction (a-adrenoceptor). 

When explaining possible medication and/or food interactions, for example the importance of avoiding alcohol with certain drugs such metronidazole or cheese with monoamine oxidase inhibitors (MAOIs). 

Because of undesirable side effects associated with monoamine oxidase inhibitor therapy (see section 2.3.2), pharmaceutical companies nearly abandoned research on new analogs in the 1960s. The early MAO inhibitors were nonselective and irreversible. Today, efforts toward the development of monoamine oxidase inhibitors are focused on selective MAQA or MAOB inhibitors. Selective MAOB inhibitors are being examined in the treatment of, for example, schizophrenia, Alzheimer s disease, and Parkinson s disease. MAO-B inhibitors might be effective in the treatment of depression, but relatively little woik has been done in this area. Selegiline... 

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