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Parnate (Tranylcypromine Sulfate) - Drug Interactions, Contraindications, Overdosage, etc

 
 



DRUG INTERACTIONS

PARNATE drug label information in our database does not contain a dedicated section on drug interactions. Please check subsections of WARNINGS AND PRECAUTIONS as well as other sources.

OVERDOSAGE

Symptoms

The characteristic symptoms that may be caused by overdosage are usually those described above.

However, an intensification of these symptoms and sometimes severe additional manifestations may be seen, depending on the degree of overdosage and on individual susceptibility. Some patients exhibit insomnia, restlessness and anxiety, progressing in severe cases to agitation, mental confusion, and incoherence. Hypotension, dizziness, weakness, and drowsiness may occur, progressing in severe cases to extreme dizziness and shock. A few patients have displayed hypertension with severe headache and other symptoms. Rare instances have been reported in which hypertension was accompanied by twitching or myoclonic fibrillation of skeletal muscles with hyperpyrexia, sometimes progressing to generalized rigidity and coma.

Treatment

Because strategies for the management of overdose are continually evolving, it is advisable to contact a Poison Control Center to determine the latest recommendations for the management of an overdose of any drug. Telephone numbers for the certified Poison Control Centers are listed in the Physicians’ Desk Reference (PDR).

Treatment should normally consist of general supportive measures, close observation of vital signs and steps to counteract specific symptoms as they occur, since MAO inhibition may persist. The management of hypertensive crises is described under WARNINGS in the HYPERTENSIVE CRISES section.

External cooling is recommended if hyperpyrexia occurs. Barbiturates have been reported to help relieve myoclonic reactions, but frequency of administration should be controlled carefully because PARNATE may prolong barbiturate activity. When hypotension requires treatment, the standard measures for managing circulatory shock should be initiated. If pressor agents are used, the rate of infusion should be regulated by careful observation of the patient because an exaggerated pressor response sometimes occurs in the presence of MAO inhibition. Remember that the toxic effect of PARNATE may be delayed or prolonged following the last dose of the drug. Therefore, the patient should be closely observed for at least a week. It is not known if tranylcypromine is dialyzable.

CONTRAINDICATIONS

PARNATE is contraindicated:

1.    In patients with cerebrovascular defects or cardiovascular disorders

PARNATE should not be administered to any patient with a confirmed or suspected cerebrovascular defect or to any patient with cardiovascular disease or hypertension.

2.   In the presence of pheochromocytoma

PARNATE should not be used in the presence of pheochromocytoma since such tumors secrete pressor substances.

3.    In combination with MAO inhibitors or with dibenzazepine-related entities

PARNATE should not be administered together or in rapid succession with other MAO inhibitors or with dibenzazepine-related entities. Hypertensive crises or severe convulsive seizures may occur in patients receiving such combinations.

In patients being transferred to PARNATE from another MAO inhibitor or from a dibenzazepine-related entity, allow a medication-free interval of at least a week, then initiate PARNATE using half the normal starting dosage for at least the first week of therapy. Similarly, at least a week should elapse between the discontinuance of PARNATE and the administration of another MAO inhibitor or a dibenzazepine-related entity, or the readministration of PARNATE.

The following list includes some other MAO inhibitors, dibenzazepine-related entities and tricyclic antidepressants, and the companies which market them.

Other MAO Inhibitors

Generic Name

Furazolidone

Isocarboxazid

Pargyline HCl

Pargyline HCl and methyclothiazide

Phenelzine sulfate

Procarbazine HCl

Dibenzazepine-Related and Other Tricyclics

Generic Name

Amitriptyline HCl

Perphenazine and amitriptyline HCl

Clomipramine hydrochloride

Desipramine HCl

Imipramine HCl

Nortriptyline HCl

Protriptyline HCl

Doxepin HCl

Carbamazepine

Cyclobenzaprine HCl

Amoxapine

Maprotiline HCl

Trimipramine maleate

4.    In combination with bupropion

The concurrent administration of an MAO inhibitor and bupropion hydrochloride (Wellbutrin®, Wellbutrin SR®, Wellbutrin XL®,  Zyban®, GlaxoSmithKline) is contraindicated. At least 14 days should elapse between discontinuation of an MAO inhibitor and initiation of treatment with bupropion hydrochloride.

5.    In combination with selective serotonin reuptake inhibitors (SSRIs) or selective norepinephrine reuptake inhibitors (SNRIs)

As a general rule, PARNATE should not be administered in combination with any SSRI or SNRI. There have been reports of serious, sometimes fatal, reactions (including hyperthermia, rigidity, myoclonus, autonomic instability with possible rapid fluctuations of vital signs, and mental status changes that include extreme agitation progressing to delirium and coma) in patients receiving a SSRI (e.g., fluoxetine) or a SNRI (e.g., venlafaxine) in combination with a monoamine oxidase inhibitor (MAOI), and in patients who have recently discontinued a SSRI or SNRI and are then started on an MAOI. Some cases presented with features resembling neuroleptic malignant syndrome. Therefore SSRIs and SNRIs should not be used in combination with an MAOI, or within 14 days of discontinuing therapy with an MAOI.

Since fluoxetine and its major metabolite have very long elimination half-lives, at least 5 weeks should be allowed after stopping fluoxetine before starting an MAOI.

At least 2 weeks should be allowed after stopping sertraline (Zoloft®, Pfizer) or paroxetine (Paxil®, Paxil CR®, GlaxoSmithKline) before starting an MAOI.

At least one week should be allowed after stopping a SNRI (e.g., venlafaxine) before starting a MAOI.

6.    In combination with buspirone

PARNATE should not be used in combination with buspirone HCl, since several cases of elevated blood pressure have been reported in patients taking MAO inhibitors who were then given buspirone HCl. At least 10 days should elapse between the discontinuation of PARNATE and the institution of buspirone HCl.

7.    In combination with sympathomimetics

PARNATE should not be administered in combination with sympathomimetics, including amphetamines which may be found in many herbal preparations as well as over-the-counter drugs such as cold, hay fever or weight-reducing preparations that contain vasoconstrictors.

During therapy with PARNATE, it appears that certain patients are particularly vulnerable to the effects of sympathomimetics when the activity of certain enzymes is inhibited. Use of sympathomimetics and compounds such as guanethidine, methyldopa, reserpine, dopamine, levodopa, and tryptophan with PARNATE may precipitate hypertension, headache, and related symptoms. Cerebral hemorrhage may also occur. The combination of MAOIs and tryptophan has been reported to cause behavioral and neurologic syndromes including disorientation, confusion, amnesia, delirium, agitation, hypomanic signs, ataxia, myoclonus, hyperreflexia, shivering, ocular oscillations, and Babinski's signs.

8.    In combination with meperidine

Do not use meperidine concomitantly with MAO inhibitors or within 2 or 3 weeks following MAOI therapy. Serious reactions have been precipitated with concomitant use, including coma, severe hypertension or hypotension, severe respiratory depression, convulsions, malignant hyperpyrexia, excitation, peripheral vascular collapse, and death. It is thought that these reactions may be mediated by accumulation of 5-HT (serotonin) consequent to MAO inhibition.

9.    In combination with dextromethorphan

The combination of MAO inhibitors and dextromethorphan has been reported to cause brief episodes of psychosis or bizarre behavior.

10.  In combination with cheese or other foods with a high tyramine content

When excessive amounts of tyramine are consumed in conjunction with tranylcypromine, or within 2 weeks of stopping treatment, a serious and sometimes fatal hypertensive reaction may occur.

Tyramine occurs naturally in some foods or may occur from the bacterial breakdown of protein in foods which are fermented, aged, or spoiled. Foods that have reliably been shown to contain a high tyramine content and may also have been reported to induce a serious hypertensive reaction when consumed with tranylcypromine are:

  • all matured or aged cheeses (note: all cheeses are considered matured or aged except fresh cottage cheese, cream cheese, ricotta, and processed cheese. All non-cheese dairy products can be consumed providing they are fresh)
  • all aged, cured or fermented meat, fish, or poultry (note: meat, fish, or poultry that has not undergone aging, curing or fermenting and that is bought fresh, stored correctly and eaten fresh is not contraindicated)
  • all fermented soybean products (e.g., soy sauce, miso, fermented tofu)
  • sauerkraut
  • fava or broad bean pods
  • banana peel (but not the pulp)
  • concentrated yeast extracts (e.g., Marmite or Vegemite spread)
  • all tap/draught beers (note: some bottled beers, including non-alcoholic beer, may also pose a risk).

Patients should be advised to minimize or avoid use of all alcoholic beverages while taking PARNATE. Patients should be advised to adhere to the following dietary guidance about eating fresh foods:

Foods may be deliberately aged as part of their processing and these are contraindicated (see list above). Foods may also naturally age over time, even if they are refrigerated. It is therefore extremely important that patients are instructed to buy and eat only fresh foods or those which have been properly frozen. They should avoid eating foods if they are unsure of their storage conditions or freshness and they should be cautious of foods of unknown age or composition even if refrigerated.

The longer food is left to deteriorate and the larger the quantity of food eaten, the greater the potential quantity of tyramine ingested. Where there is any doubt, patients should be advised to either avoid the food or consume it in strict moderation if it is not otherwise contraindicated.

Patients should also be warned that tyramine levels may vary by brand or even batch and a person may absorb different amounts of tyramine from a particular food at different times. Therefore, if they have accidentally consumed a prohibited food on one occasion and not had a reaction, this does not mean that they will not have a serious hypertensive reaction if they consume the same food on a different occasion.

11.   In patients undergoing elective surgery

Patients taking PARNATE should not undergo elective surgery requiring general anesthesia. Also, they should not be given cocaine or local anesthesia containing sympathomimetic vasoconstrictors. The possible combined hypotensive effects of PARNATE and spinal anesthesia should be kept in mind. PARNATE should be discontinued at least 10 days prior to elective surgery.

ADDITIONAL CONTRAINDICATIONS

In general, the physician should bear in mind the possibility of a lowered margin of safety when PARNATE is administered in combination with potent drugs.

1. PARNATE should not be used in combination with some central nervous system depressants such as narcotics and alcohol, or with hypotensive agents. A marked potentiating effect on these classes of drugs has been reported.

2. Anti-parkinsonism drugs should be used with caution in patients receiving PARNATE since severe reactions have been reported.

3. PARNATE should not be used in patients with a history of liver disease or in those with abnormal liver function tests.

4. Excessive use of caffeine in any form should be avoided in patients receiving PARNATE.

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