phenelzine (Rx)

Brand and Other Names:Nardil
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Dosing & Uses

AdultPediatricGeriatric

Dosage Forms & Strengths

tablet

  • 15mg

Depression

Initial 15 mg PO q8hr, increase not to exceed 20-30 mg q8hr

Dosage should be increased to at least 60 mg/day at a fairly rapid pace consistent with patient tolerance; may be necessary to increase dosage up to 90 mg/day to obtain sufficient MAO inhibition; many patients do not show a clinical response until treatment at 60 mg has been continued for at least 4 weeks

After maximum benefit from drug is achieved, decrease dose after maximum response (2-6 weeks) over 2-6 week period to maintain dose as low as 15 mg qDay or every other day

Monitor blood pressure

Dose considerations

  • When discontinuing antidepressant therapy lasting for >3 weeks, gradually taper dose over 2-4wk to minimize withdrawal adverse effects

Safety & efficacy not established

Depression

Initial 15 mg PO q8hr, increase not to exceed 20-30 mg q8hr

Decrease dose after maximum response (2-6 weeks) over 2-6 week period to maintain dose as low as 15 mg qDay or every other day

Monitor blood pressure

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Interactions

Interaction Checker

and phenelzine

No Results

     activity indicator 
    No Interactions Found
    Interactions Found

    Contraindicated

      Serious - Use Alternative

        Significant - Monitor Closely

          Minor

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            Adverse Effects

            Frequency Not Defined

            Common

            • Orthostatic hypotension
            • Asthenia
            • Dizziness
            • Headache
            • Drowsiness
            • Fatigue
            • Hyperreflexia
            • Sleep disturbance
            • Somnolence
            • Weakness
            • Tremor
            • Constipation
            • Dry mouth
            • Weight gain

            Less Common

            • Confusion
            • Decreased memory
            • Paresthesia
            • Anorexia
            • Nausea
            • Vomiting
            • Impotence
            • Increased LFT's
            • Nystagmus
            • Urinary frequency or retention

            Uncommon

            • Edema
            • Anxiety
            • Irritation
            • Hypomania
            • Hypermetabolic syndrome (hyperpyrexia, tachycardia, tachypnea, increased CPK, acidosis)
            • Arthralgia
            • SIADH

            Rare

            • Hypertensive crisis
            • Ataxia
            • Seizure
            • Worsening depression
            • Suicide
            • Edema of glottis
            • Leukopenia
            • Hepatic necrosis, jaundice
            • Drug-induced lupus erythematosus
            • Visual disturbance
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            Warnings

            Black Box Warnings

            In short-term studies, antidepressants increased the risk of suicidal thinking and behavior in children, adolescents, and young adults (<24 yr of age) taking antidepressants for major depressive disorders and other psychiatric illnesses

            This increase was not seen in patients aged >24 years; a slight decrease in suicidal thinking was seen in adults >65 years

            In children and young adults, risks must be weighed against the benefits of taking antidepressants

            Patients should be monitored closely for changes in behavior, clinical worsening, and suicidal tendencies; this should be done during initial 1-2 months of therapy and dosage adjustments

            The patient’s family should communicate any abrupt changes in behavior to the healthcare provider

            Worsening behavior and suicidal tendencies that are not part of the presenting symptoms may require discontinuation of therapy

            This drug is not approved for use in pediatric patients

            Contraindications

            Hypersensitivity

            Pheochromocytoma, congestive heart failure

            Within 10 days of elective surgery using general anesthesia or spinal anesthesia

            Liver disease, abnormal liver function tests, or history of hepatic disease

            Renal disease, severe renal impairment, ESRD

            Cautions

            Orthostatic hypotension may occur

            Hypertensive reactions may occur from consumption of foods high in tyramine or supplements containing caffeine, tyrosine, tryptophan, phenylalanine, or phenylalanine

            Not first-line therapy

            Discontinue 10 days before surgery

            Therapy not approved for treating any indications in the pediatric population

            Most serious reactions involve changes in blood pressure

            Therapy may cause excessive stimulation in schizophrenic patients

            Drug potentiates hexobarbital hypnosis in animals; barbiturates should be given at a reduced dose with phenelzine

            Drug should be used with caution in diabetes mellitus; increased insulin sensitivity may occur; requirements for insulin or oral hypoglycemics may be decreased; there is conflicting evidence as to whether or not MAO inhibitors affect glucose metabolism or potentiate hypoglycemic agents; this should be kept in mind if drug is administered to diabetics

            Hypertensive crises

            • Most important reaction associated with therapy is the occurrence of hypertensive crises, which have sometimes been fatal
            • The crises are characterized by occipital headache which may radiate frontally, palpitation, neck stiffness or soreness, nausea, vomiting, sweating (sometimes with fever and sometimes with cold, clammy skin), dilated pupils, and photophobia; either tachycardia or bradycardia may be present and can be associated with constricting chest pain
            • Intracranial bleeding has been reported in association with increase in blood pressure; blood pressure should be observed frequently to detect evidence of any pressor response in all patients receiving therapy; therapy should be discontinued immediately upon occurrence of palpitation or frequent headaches during therapy
            • If a hypertensive crisis occurs, drug should be discontinued immediately and therapy to lower blood pressure should be instituted immediately; on the basis of present evidence, phentolamine is recommended; dosage reported for phentolamine is 5 mg intravenously; care should be taken to administer this drug slowly in order to avoid producing an excessive hypotensive effect; fever should be managed by means of external cooling

            Suicide risk

            • Patients with major depressive disorder (MDD), both adult and pediatric, may experience worsening of their depression and/or the emergence of suicidal ideation and behavior (suicidality) or unusual changes in behavior, whether or not they are taking antidepressant medications, and this risk may persist until significant remission occurs
            • Unknown whether the suicidality risk extends to longer-term use, ie, beyond several months; however, there is substantial evidence from placebo-controlled maintenance trials in adults with depression that the use of antidepressants can delay the recurrence of depression
            • All patients being treated with antidepressants for any indication should be monitored appropriately and observed closely for clinical worsening, suicidality, and unusual changes in behavior, especially during the initial few months of a course of drug therapy, or at times of dose changes, either increases or decrease
            • The following symptoms, anxiety, agitation, panic attacks, insomnia, irritability, hostility, aggressiveness, impulsivity, akathisia (psychomotor restlessness), hypomania, and mania, reported in adult and pediatric patients being treated with antidepressants for major depressive disorder as well as for other indications, both psychiatric and nonpsychiatric; although a causal link between emergence of such symptoms and either the worsening of depression and/or emergence of suicidal impulses has not been established, there is concern that such symptoms may represent precursors to emerging suicidality
            • Consider changing the therapeutic regimen, including possibly discontinuing the medication, in patients whose depression is persistently worse, or who are experiencing emergent suicidality or symptoms that might be precursors to worsening depression or suicidality, especially if these symptoms are severe, abrupt in onset, or were not part of the patient's presenting symptoms
            • Families and caregivers of patients being treated with antidepressants for major depressive disorder or other indications, both psychiatric and nonpsychiatric, should be alerted about need to monitor patients for emergence of agitation, irritability, unusual changes in behavior; monitoring should include daily observation by families and caregivers; prescriptions should be written for smallest quantity of tablets consistent with good patient management, in order to reduce risk of overdose

            Bipolar disorder

            • A major depressive episode may be initial presentation of bipolar disorder; it is generally believed that treating such an episode with an antidepressant alone may increase likelihood of precipitation of a mixed/manic episode in patients at risk for bipolar disorder; whether any of the symptoms of depression described represent such a conversion is unknown
            • Of the more severe side effects reported with any consistency, hypomania has been the most common; this reaction has been largely limited to patients in whom disorders characterized by hyperkinetic symptoms coexist with, but are obscured by, depressive affect; hypomania usually appeared as depression improved; if agitation is present, may be increased with therapy; hypomania and agitation have also been reported at higher than recommended doses or following long-term therapy
            • Prior to initiating treatment with an antidepressant, patients with depressive symptoms should be adequately screened to determine if they are at risk for bipolar disorder; such screening should include a detailed psychiatric history, including a family history of suicide, bipolar disorder, and depression; therapy is not approved to treat bipolar depression

            Drug interaction overview

            • In patients receiving nonselective monoamine oxidase (MAO) inhibitors in combination with serotoninergic agents there have been reports of serious, sometimes fatal, reactions; phenelzine should not be used concomitantly with a serotoninergic agent
            • Administration of guanethidine to patients receiving a MAO inhibitor can produce moderate to severe hypertension due to release of catecholamines; at least two weeks should elapse between withdrawal of MAO inhibitor and initiation of guanethidine
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            Pregnancy & Lactation

            Pregnancy Category: C

            Lactation: unknown; use caution

            Pregnancy Categories

            A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

            B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

            C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

            D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

            X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

            NA: Information not available.

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            Pharmacology

            Mechanism of Action

            Nonselective monoamine oxidase inhibitor; may inhibit the enzyme monoamine oxidase, which is responsible for the breakdown of dopamine, serotonin, epinephrine, and norepinephrine, in turn causing an increase in endogenous concentrations of these neurotransmitters.

            Pharmacokinetics

            Peak Plasma Time: 43 min

            Metabolism: by MAO

            Onset of action: 2-4 weeks

            Duration: Therapeutic effects and interactions may continue for up to 2 weeks after discontinuing therapy

            Metabolites: phenylacetic acid & parahydroxyphenylacetic acid

            Half-Life, Elimination: 11.6 hr

            Excretion: Urine

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            Formulary

            FormularyPatient Discounts

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            The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

            Tier Description
            1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
            2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
            3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
            4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            NC NOT COVERED – Drugs that are not covered by the plan.
            Code Definition
            PA Prior Authorization
            Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
            QL Quantity Limits
            Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
            ST Step Therapy
            Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
            OR Other Restrictions
            Drugs that have restrictions other than prior authorization, quantity limits, and step therapy associated with each prescription.
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            Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.