Crisis hypertensive

The nitrovasodilator sodium nitroprusside (SNP) has been used for decades to manage acute hypertensive crises and congestive heart failure complicating myocardial ischemia [99]. However, prolonged SNP administration is limited by tolerance, the... 

Tyramine is an amino acid which is present in large quantities in protein rich, fermented and stored products like some cheeses, sausages, red wines, beers etcetera. Tyramine is metabolized into nor-adrenaline by the enzyme mono-amino-oxidase (MAO). If MAO is inhibited by drags nor-adrenaline is accumulated and can give hypertensive crises. 

MAOIs, although effective, are also problematic for routine use in the treatment of BN. First, like the TCAs, MAOIs have a propensity for lowering blood pressure. Additionally, bulimia patients, who are by definition prone to impulsive out of control eating, are not ideal candidates to maintain the strict tyramine-free diet restrictions imposed by MAOIs. Thus, they run a substantial risk of precipitating dangerous hypertensive crises through dietary noncompliance while taking MAOIs. It remains unclear whether the reversible MAOIs such as moclobemide will prove effective in the treatment of BN without the risks associated with other MAOIs. 

The main limitation to the clinical use of the MAOIs is due to their interaction with amine-containing foods such as cheeses, red wine, beers (including non-alcoholic beers), fermented and processed meat products, yeast products, soya and some vegetables. Some proprietary medicines such as cold cures contain phenylpropanolamine, ephedrine, etc. and will also interact with MAOIs. Such an interaction (termed the "cheese effect"), is attributed to the dramatic rise in blood pressure due to the sudden release of noradrenaline from peripheral sympathetic terminals, an event due to the displacement of noradrenaline from its mtraneuronal vesicles by the primary amine (usually tyramine). Under normal circumstances, any dietary amines would be metabolized by MAO in the wall of the gastrointestinal tract, in the liver, platelets, etc. The occurrence of hypertensive crises, and occasionally strokes, therefore limited the use of the MAOIs, despite their proven clinical efficacy, to the treatment of atypical depression and occasionally panic disorder. 

Diazoxide given i.v. causes prominent arteriolar dilation it can be employed in hypertensive crises. After its oral administration, insulin secretion is inhibited. Accordingly, diazoxide can be used in the management of insulin-secreting pancreatic tumors. Both effects are probably due to opening of (ATP-gated) K+ channels. 

Drugs for the control of hypertensive crises include nifedipine (capsule, to be chewed and swallowed), nitroglycerin (sublingually), clonidine (p.o. or i.v., p. 96), dihydralazine (i.v.), diazoxide (i.v.), fenoldopam (by infusion, p. 114) and sodium nitroprusside (p. 120, by infusion). The nonselective a-blocker phentolamine (p. 90) is indicated only in pheochromocytoma... 

It is prescribed for arterial hypertension and hypertensive crises. Synonyms of this drug are aldomet, dopegit, mopatil, and others. 

Sodium nitroprusside is a powerful, instantaneous-acting intravenous drug used to lower blood pressure in hypertensive crises. The hypotensive effect is caused by peripheral vasodilation resulting from a direct effect on both arterial and venous vessels. 

Methyidopate hydrochloride may be used to initiate treatment of acute hypertensive crises however, due to its slow onset of action, other agents may be preferred for rapid reduction of blood pressure. 

Advanced arteriosclerosis symptomatic cardiovascular disease moderate to severe hypertension hyperthyroidism hypersensitivity or idiosyncrasy to the sympathomimetic amines glaucoma agitated states history of drug abuse during or within 14 days following administration of monoamine oxidase (MAO) inhibitors (hypertensive crises may result). 

Hypertensive crises The most serious reactions involve changes in blood pressure it is inadvisable to use these drugs in elderly or debilitated patients or in the presence of hypertension, cardiovascular, or cerebrovascular disease. Not recommended in patients with frequent or severe headaches because headache during therapy may be the first symptom of a hypertensive reaction. 

Patients with marked anxiety, tension, and agitation, because the drug may aggravate these symptoms hypersensitivity to methylphenidate or other components of the product patients with glaucoma, motor tics, or a family history or diagnosis of Tourette s syndrome during treatment with monoamine oxidase inhibitors (MAOIs), and also within a minimum of 14 days following discontinuation of an MAOl (hypertensive crises may result). 

Can antidepressants such as tricyclics or buproprion augment the effect of stimulants on nondepressed children with ADHD Randomized controlled trials have yet to address this question. Nonetheless, such combinations are common in clinical practice. One case report showed leukopenia in a child treated with a combination of MPH and tricyclics for 4 months, although the doses were not specified (Burke et ah, 1995). Another case report indicated that obsessive-compulsive symptoms developed secondary to the combination of MPH and tricyclics (Pataki et ah, 1993). On a cautionary note, MPH has been found to interact with guanethidine to produce paradoxical hypotension. Patients on monoamine oxidose (MAO) inhibitors are likely to develop hypertensive crises if given a stimulant. 

Hypertensive crises are characterized initially by headache, but can evolve to include neck stiffness, chest discomfort, palpitations, confusion, and, ultimately, hemorrhage or stroke. Treatment of MAOI-associated hypertension may include a watch-and-wait stance by the patient if the symptoms are mild. Some patients have the ability to check and monitor their own blood pressure. Others may consult with a physician for blood pressure checks and observation, but if symptoms are severe, the patient may need to go to an emergency room or self-medicate. Standard emergency room treatment is intravenous phentolamine, an a-adrenergic blocker, continuous monitoring and management until blood pressure is normalized without medication. Some doctors will provide patients with small doses of chlorpromazine or nifedipine to treat hypertension if a problem arises. 

Phenelzine and tranylcypromine are both effective in the treatment of social phobia. Many practitioners continue to be hesitant to use this class of medications, given the dietary restrictions required of patients and the potential risk of hypertensive crises when combined with dietary tyramine and sympathomimetic medications. However, the proven effectiveness of this class makes it an important option in the treatment of social phobia. 

Unfortunately, even perfect compliance with dietary and other restrictions does not guarantee complete protection from MAOI-induced hypertensive crises. There are reports of spontaneous hypertension associated with MAOI therapy. Most of these involved the use of tranylcypromine, but phenelzine also has been implicated. 

MAOIs fall between TCAs and SSRIs in terms of lethality in overdose. Most complications related to MAOI overdose arise from the drugs stimulation of the sympathetic nervous system. MAOIs are most dangerous when patients experience hypertensive crises as the result of ingesting foods with high tyramine content. 

Pharmacologic doses of pyridoxine (vitamin B6 ) enhance the extracerebral metabolism of levodopa and may therefore prevent its therapeutic effect unless a peripheral decarboxylase inhibitor is also taken. Levodopa should not be given to patients taking monoamine oxidase A inhibitors or within 2 weeks of their discontinuance because such a combination can lead to hypertensive crises. 

The combined administration of levodopa and an inhibitor of both forms of monoamine oxidase (ie, a nonselective inhibitor) must be avoided, because it may lead to hypertensive crises, probably because of the peripheral accumulation of norepinephrine. 

During clinical studies of iproniazid (201) in the treatment of tuberculosis it was found to have a mood-elevating effect. It was later found to be an inhibitor of monoamine oxidase (MAO), the enzyme which oxidatively deaminates such neurotransmitters as noradrenaline and serotonin, and it was tried in the treatment of depression in 1957. Other MAO inhibitors were introduced later, most of them being hydrazine derivatives. Heterocyclic examples include isocarboxazid (202) and nialamide (203). They are toxic and cause dangerous hypertensive crises if food with a high tyramine content is eaten, and on this account their use is limited. 

Monoamine oxidase (MAO) inhibitors Foods containing tyramine (liver, pickled herring, cheese, bananas, avocados, soup, beer, wine, yogurt, sour cream, yeast, nuts) Palpitations, headache, hypertensive crises... 

The pioneer drug, captopril, had a relatively short duration of action. Nonetheless, with sublingual administration it is used to elicit beneficial hemodynamic and clinical effects in hypertensive crises, acute myocardial ischemia, and acute CHF. Several long-acting analogue drugs are used nowadays as a first-choice therapy in cardiovascular diseases, and their minor differences have been summarized in this chapter. 

Hypertensive crises usually occur when MAO inhibitors are combined with other drugs or foods that cause interactions (see next subsection). 

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