Monoamine oxidase with food

Treatment is basically symptomatic and supportive no specific antidotes are available. Artificial ventilation with 100% humidified oxygen is necessary in cases of respiratory distress. If patient is cyanotic and cyanosis does not respond to oxygen administration, methemoglobin levels should be determined. Methemoglobinemia can be treated by intravenous administration of methylene blue. Support of cardiovascular function may also be required. Bladder damage can be determined by urinalysis. Hypotension may be treated with isotonic intravenous fluids. Dopamine or norepinephrine may be used if hypotension does not respond to infusion of fluids. Convulsions may be treated with intravenous benzodiazepines (diazepam or loraze-pam) phenobarbital may be used if the convulsions are recurrent. Because chlordimeform is a monoamine oxidase inhibitor, foods with large amounts of... 

Reversible Inhibitors of Monoamine Oxidase. Selective MAO-A inhibitors, which aie leveisible (so-called RIMAs), have also been developed, theiefoie substantially leduciag the potential foi food and dmg iateiactions. Indeed, the tyiamine-potentiating effects of these dmgs is much reduced compared with the irreversible MAO inhibitors. The RIMAs represent effective and safer alternatives to the older MAO inhibitors. The only marketed RIMAs ate toloxatone [29218-27-7] and moclobemide (55). The latter is used widely as an effective, weU-tolerated antidepressant. 

Levodopa interacts with many different drugs. When levodopa is used with phenytoin, reserpine, and papaverine, there is a decrease in response to levodopa The risk of a hypertensive crisis increases when levodopa is used with the monoamine oxidase inhibitors (see Chap. 31). Foods high in pyridoxine (vitamin B6) or vitamin B6 preparations reverse the effect of levodopa However, when carbidopa is used with levodopa, pyridoxine has no effect on the action of levodopa hi fact, when levodopa and carbidopa are given together, pyridoxine may be prescribed to decrease the adverse effects associated with levodopa... 

FIGURE 29-2. Levodopa absorption and metabolism. Levodopa is absorbed in the small intestine and is distributed into the plasma and brain compartments by an active transport mechanism. Levodopa is metabolized by dopa decarboxylase, monoamine oxidase, and catechol-O-methyltransferase. Carbidopa does not cross the blood-brain barrier. Large, neutral amino acids in food compete with levodopa for intestinal absorption (transport across gut endothelium to plasma). They also compete for transport across the brain (plasma compartment to brain compartment). Food and anticholinergics delay gastric emptying resulting in levodopa degradation in the stomach and a decreased amount of levodopa absorbed. If the interaction becomes a problem, administer levodopa 30 minutes before or 60 minutes after meals. 

Myelosuppression is the major side effect. Nausea, vomiting, and a flulike syndrome occur initially with therapy. Patients must be counseled to avoid tyramine-rich foods because procarbazine is a monoamine oxidase inhibitor. Patients should be provided a list of foods and beverages to avoid to prevent a hypertensive crisis. A disulhramlike reaction can occur with the ingestion of alcohol. 

MAOIs work by inhibiting a brain enzyme called monoamine oxidase. Patients taking MAOIs must avoid a substantial list of foods that can interact with the medication and cause dangerously high blood pressure. 

Newer MAOI drugs are selective for the MAO-A subtype of the enzyme, and are less likely to interact with foods or other drugs. Monoamine oxidase (MAO) inactivates monoamine substances, many of which are, or are related to, neurotransmitters. The central nervous system mainly contains MAO-A, whose substrates are adrenaline (epinephrine), noradrenaline (norepinephrine), metanephrine, and 5-hydroxyti7ptamine (5-HT), whereas extra-neuronal tissues, such as the liver, lung, and kidney, contain mainly MAO-B which metabolises p-phenylethylamine, phenylethanolamine, o-tyramine, and benzylamine. 

Monoamine oxidase inhibitors (eg, tranylcypromine, phenelzine) are older antidepressants that are occasionally used for resistant depression. They can cause severe hypertensive reactions when interacting foods or drugs are taken (see Chapters 9 and 30), and they can interact with the selective serotonin reuptake inhibitors (SSRIs). 

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. 

Desmethylselegiline is also an irreversible inhibitor of monoamine oxidase B in humans. There is evidence that the 1-stereoisomers of 1-amphetamine and 1-methamphetamine may have some qualitatively different actions from their d-isomer counterparts, which might result in beneficial clinical effects and could complement any beneficial clinical actions of selegiline itself. Food has no effect on the pharmacokinetics of desmethylselegiline, methamphetamine, and amphetamine. At a dose of 10 mg per day, selegiline is devoid of the cheese effect that is, it does not cause hypertension when taken with tyramine-containing foods such as cheese. 

Q14 MAOIs, such as phenelzine and isocarboxazid, affect the sympathetic nervous system by inhibiting one or both forms of brain monoamine oxidase. Their sympathomimetic effects can produce a feeling of well-being and increased energy, which is helpful for depressed patients. However, psychosis may occur in a susceptible individual or may follow over-administration of these agents. An increase in sympathomimetic action (such as occurs with use of amphetamines, which increase the release of noradrenaline) can result in a lethal hypertensive crisis. In addition, a hypertensive crisis can also be initiated if the patient consumes a diet rich in amines foods with a high amine content include cheese, pickles, broad beans and wine. 

The monoamine oxidase inhibitors epitomize cyclical fashions in drug use and the impact of adverse effects. They were the first psychotropic drugs for which a clear biochemical action was defined. Early excitement was quickly tempered by reports of liver toxicity with the hydrazine derivatives, leading to synthesis of the cyclopropylamine drug, tranylcypromine, which in turn elicited the food and drug interactions that led to an overall decline in popularity. 

Procarbazine is a weak inhibitor of monoamine oxidase adverse drug and food interactions can occur, for example with tyramine-containing foods and drinks,... 

St. John s wort is a monoamine oxidase inhibitor, and the authors believed that this explained how the concomitant use of a tyramine-rich food with St. John s wort had caused this problem. 

Fnrazohdone is used in the treatment of giardiasis. Its adverse effects are usually mild and transient abdominal discomfort, nausea, and vomiting. The urine may be dark-colored (SEDA-11, 597). Metabolites of furazolidone inhibit monoamine oxidase (1) and there is therefore the potential for interactions with foods containing tyramine (2) and with opioid analgesics hyperpyrexia has been reported in rabbits that were given fnrazohdone and pethidine (3). 

Phentolamine is a non-selective alpha-adrenoceptor antagonist. It is used to treat hypertensive crises attributable to the effects of noradrenahne, as in pheochromo-cytoma and during the interaction of monoamine oxidase inhibitors with amine-containing medicaments and foods (1). Its adverse effects are similar to those of phenoxy-benzamine. 

St. John s Wort (Hypericum perforatum) St. John s wort, known as herbal Prozac, treats depression, anxiety, and psychogenic disturbance similar to monoamine oxidase (MAO). Patients who use St. John s Wort do not have to avoid tyramine-rich foods, which is the case with patients who take MAO. St. John s Wort is a dietary supplement. 

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). 

Administered as a single, daily dose on an empty stomach Monoamine oxidase inhibitors drug-food interactions with tyramine-rich foods such as red wines, dark beers, aged cheeses, yogurt may precipitate hypertensive crisis drug interactions tricyclic antidepressants and SSRIs, sympathomimetics disulfiram-like reaction with alcohol... 

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