DEXTROAMPHETAMINE Drug Interactions: What You Need to Know

Drug Interactions MAO Inhibitors - MAOI antidepressants, as well as a metabolite of furazolidone, slow amphetamine metabolism. This slowing potentiates amphetamines, increasing their effect on the release of norepinephrine and other monoamines from adrenergic nerve endings; this can cause headaches and other signs of hypertensive crisis. A variety of neurological toxic effects and malignant hyperpyrexia can occur, sometimes with fatal results.

Serotonergic

Drugs - The concomitant use of dextroamphetamine sulfate oral solution and serotonergic drugs increases the risk of serotonin syndrome. Initiate with lower doses and monitor patients for signs and symptoms of serotonin syndrome, particularly during dextroamphetamine sulfate oral solution initiation or dosage increase. If serotonin syndrome occurs, discontinue dextroamphetamine sulfate oral solution and the concomitant serotonergic drug(s) (see WARNINGS , PRECAUTIONS ) . Examples of serotonergic drugs include selective serotonin reuptake inhibitors (SSRI), serotonin norepinephrine reuptake inhibitors (SNRI), triptans, tricyclic antidepressants, fentanyl, lithium, tramadol, tryptophan, buspirone, St. John’s Wort. CYP2D6 Inhibitors - The concomitant use of dextroamphetamine sulfate oral solution and CYP2D6 inhibitors may increase the exposure of dextroamphetamine sulfate oral solution compared to the use of the drug alone and increase the risk of serotonin syndrome. Initiate with lower doses and monitor patients for signs and symptoms of serotonin syndrome particularly during dextroamphetamine sulfate oral solution initiation and after a dosage increase. If serotonin syndrome occurs, discontinue dextroamphetamine sulfate oral solution and the CYP2D6 inhibitor (see WARNINGS , OVERDOSAGE ) . Examples of CYP2D6 Inhibitors include paroxetine and fluoxetine (also serotonergic drugs), quinidine, ritonavir.

Acidifying

Agents – Gastrointestinal acidifying agents (guanethidine, reserpine, glutamic acid HCl, ascorbic acid, fruit juices, etc.) lower absorption of amphetamines. Urinary acidifying agents (ammonium chloride, sodium acid phosphate, etc.) increase the concentration of the ionized species of the amphetamine molecule, thereby increasing urinary excretion. Both groups of agents lower blood levels and efficacy of amphetamines.

Adrenergic

Blockers – Adrenergic blockers are inhibited by amphetamines.

Alkalinizing

Agents – Gastrointestinal alkalinizing agents (sodium bicarbonate, etc.) increase absorption of amphetamines. Urinary alkalinizing agents (acetazolamide, some thiazides) increase the concentration of the non-ionized species of the amphetamine molecule, thereby decreasing urinary excretion. Both groups of agents increase blood levels and therefore potentiate the actions of amphetamines. Antidepressants, Tricyclic – Amphetamines may enhance the activity of tricyclic or sympathomimetic agents; d-amphetamine with desipramine or protriptyline and possibly other tricyclics cause striking and sustained increases in the concentration of d-amphetamine in the brain; cardiovascular effects can be potentiated. Antihistamines – Amphetamines may counteract the sedative effect of antihistamines. Antihypertensives – Amphetamines may antagonize the hypotensive effects of antihypertensives. Chlorpromazine – Chlorpromazine blocks dopamine and norepinephrine reuptake, thus inhibiting the central stimulant effects of amphetamines, and can be used to treat amphetamine poisoning. Ethosuximide – Amphetamines may delay intestinal absorption of ethosuximide. Haloperidol – Haloperidol blocks dopamine and norepinephrine reuptake, thus inhibiting the central stimulant effects of amphetamines.

Lithium

Carbonate – The stimulatory effects of amphetamines may be inhibited by lithium carbonate. Meperidine – Amphetamines potentiate the analgesic effect of meperidine.

Methenamine

Therapy – Urinary excretion of amphetamines is increased, and efficacy is reduced, by acidifying agents used in methenamine therapy. Norepinephrine – Amphetamines enhance the adrenergic effect of norepinephrine. Phenobarbital – Amphetamines may delay intestinal absorption of phenobarbital; co-administration of phenobarbital may produce a synergistic anticonvulsant action. Phenytoin – Amphetamines may delay intestinal absorption of phenytoin; co-administration of phenytoin may produce a synergistic anticonvulsant action. Propoxyphene – In cases of propoxyphene overdosage, amphetamine CNS stimulation is potentiated and fatal convulsions can occur.

Veratrum

Alkaloids – Amphetamines inhibit the hypotensive effect of veratrum alkaloids.

Drug/Laboratory

Test Interactions Amphetamines can cause a significant elevation in plasma corticosteroid levels. This increase is greatest in the evening. Amphetamines may interfere with urinary steroid determinations.

Carcinogenesis/Mutagenesis

Mutagenicity studies and long-term studies in animals to determine the carcinogenic potential of dextroamphetamine sulfate have not been performed.

Pregnancy Teratogenic Effects Pregnancy

Category C Dextroamphetamine sulfate has been shown to have embryotoxic and teratogenic effects when administered to A/Jax mice and C57BL mice in doses approximately 41 times the maximum human dose. Embryotoxic effects were not seen in New Zealand white rabbits given the drug in doses 7 times the human dose nor in rats given 12.5 times the maximum human dose. While there are no adequate and well-controlled studies in pregnant women, there has been one report of severe congenital bony deformity, tracheoesophageal fistula, and anal atresia (VATER association) in a baby born to a woman who took dextroamphetamine sulfate with lovastatin during the first trimester of pregnancy. Dextroamphetamine sulfate should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Nonteratogenic Effects

Infants born to mothers dependent on amphetamines have an increased risk of premature delivery and low birth weight. Also, these infants may experience symptoms of withdrawal as demonstrated by dysphoria, including agitation, and significant lassitude.

Nursing Mothers

Amphetamines are excreted in human milk. Mothers taking amphetamines should be advised to refrain from nursing.

Pediatric Use

Long-term effects of amphetamines in pediatric patients have not been well established. Amphetamines are not recommended for use in pediatric patients under 3 years of age with Attention Deficit Disorder with Hyperactivity described under INDICATIONS AND USAGE . Clinical experience suggests that in psychotic children, administration of amphetamines may exacerbate symptoms of behavior disturbance and thought disorder. Amphetamines have been reported to exacerbate motor and phonic tics and Tourette’s syndrome. Therefore, clinical evaluation for tics and Tourette’s syndrome in children and their families should precede use of stimulant medications. Data are inadequate to determine whether chronic administration of amphetamines may be associated with growth inhibition; therefore, growth should be monitored during treatment. Drug treatment is not indicated in all cases of Attention Deficit Disorder with Hyperactivity and should be considered only in light of the complete history and evaluation of the child. The decision to prescribe amphetamines should depend on the physician’s assessment of the chronicity and severity of the child’s symptoms and their appropriateness for his or her age. Prescription should not depend solely on the presence of one or more of the behavioral characteristics. When these symptoms are associated with acute stress reactions, treatment with amphetamines is usually not indicated.

CONTRAINDICATIONS Advanced arteriosclerosis, symptomatic cardiovascular disease, moderate to severe hypertension, hyperthyroidism, known hypersensitivity or idiosyncrasy to the sympathomimetic amines, glaucoma. Agitated states. Patients with a history of drug abuse. Known hypersensitivity or idiosyncrasy to amphetamine. In patients known to be hypersensitive to amphetamine, or other components of dextroamphetamine sulfate. Hypersensitivity reactions such as angioedema and anaphylactic reactions have been reported in patients treated with other amphetamine products [see Adverse Reactions ]. Patients taking monoamine oxidase inhibitors (MAOIs), or within 14 days of stopping MAOIs (including MAOIs such as linezolid or intravenous methylene blue), because of an increased risk of hypertensive crisis [see Warnings and Drug Interactions ].

AND PRECAUTIONS Risks to Patients with Serious Cardiac Disease: Avoid use in patients with known structural cardiac abnormalities, cardiomyopathy, serious cardiac arrhythmias, coronary artery disease, or other serious cardiac disease ( 5.2 )

Increased Blood

Pressure and Heart Rate: Monitor blood pressure and pulse ( 5.3 )

Psychiatric Adverse

Reactions: Prior to initiating XELSTRYM, screen patients for risk factors for developing a manic episode. If new psychotic or manic symptoms occur, consider discontinuing XELSTRYM ( 5.4 ) Long-Term Suppression of Growth in Pediatric Patients: Closely monitor growth (height and weight) in pediatric patients. Pediatric patients not growing or gaining height or weight as expected may need to have their treatment interrupted ( 5.5 )

Peripheral

Vasculopathy, including Raynaud’s phenomenon: Careful observation for digital changes is necessary during XELSTRYM treatment. Further clinical evaluation (e.g., rheumatology referral) may be appropriate for patients who develop signs or symptoms of peripheral vasculopathy ( 5.6 )

Serotonin

Syndrome: Increased risk when co-administered with serotonergic agents (e.g., SSRIs, SNRIs, triptans), but also during overdosage situations. If it occurs, discontinue XELSTRYM and initiate supportive treatment ( 5.7 , 10 )

Contact

Sensitization: Use of XELSTRYM may lead to contact sensitization. Discontinue XELSTRYM if contact sensitization is suspected ( 5.8 )

Application Site

Reactions: During wear time or immediately after removal of XELSTRYM, local skin reactions may occur. Select a different application site each day to limit the occurrence of skin reactions ( 5.9 )

External

Heat: Avoid exposing XELSTRYM to external heat sources during wear because both the rate and extent of absorption are increased ( 5.10 ) Motor and Verbal Tics, and Worsening of Tourette's Syndrome: Before initiating XELSTRYM, assess the family history and clinically evaluate patients for tics or Tourette’s syndrome. Regularly monitor patients for the emergence or worsening of tics or Tourette’s syndrome. Discontinue treatment if clinically appropriate ( 5.11 )

5.1 Abuse, Misuse, and Addiction XELSTRYM has a high potential for abuse and misuse. The use of XELSTRYM exposes individuals to the risks of abuse and misuse, which can lead to the development of a substance use disorder, including addiction. XELSTRYM can be diverted for non-medical use into illicit channels or distribution <span class="opacity-50 text-xs">[see Drug Abuse and Dependence (9.2) ]</span> . Misuse and abuse of CNS stimulants, including XELSTRYM, can result in overdose and death <span class="opacity-50 text-xs">[see Overdosage (10) ]</span> , and this risk is increased with higher doses or unapproved methods of administration, such as snorting or injection. Before prescribing XELSTRYM, assess each patient’s risk for abuse, misuse, and addiction. Educate patients and their families about these risks and proper disposal of any unused drug. Advise patients to store XELSTRYM in a safe place, preferably locked, and instruct patients to not give XELSTRYM to anyone else. Throughout XELSTRYM treatment, reassess each patient’s risk of abuse, misuse, and addiction and frequently monitor for signs and symptoms of abuse, misuse, and addiction.

5.2 Risks to Patients with Serious Cardiac Disease Sudden death has been reported in patients with structural cardiac abnormalities or other serious cardiac disease who were treated with CNS stimulants at the recommended ADHD dosage. Avoid XELSTRYM use in patients with known structural cardiac abnormalities, cardiomyopathy, serious cardiac arrhythmia, coronary artery disease, or other serious cardiac disease.

5.3 Increased Blood Pressure and Heart Rate CNS stimulants cause an increase in blood pressure (mean increase about 2 to 4 mm Hg) and heart rate (mean increase about 3 to 6 bpm). Monitor all XELSTRYM-treated patients for potential tachycardia and hypertension.

5.4 Psychiatric Adverse Reactions Exacerbation of Pre-existing Psychosis CNS stimulants may exacerbate symptoms of behavior disturbance and thought disorder in patients with a pre-existing psychotic disorder. Induction of a Manic Episode in Patients with Bipolar Disorder CNS stimulants may induce a manic or mixed episode in patients. Prior to initiating XELSTRYM treatment, screen patients for risk factors for developing a manic episode (e.g., comorbid or history of depressive symptoms or a family history of suicide, bipolar disorder, and depression).

New

Psychotic or Manic Symptoms CNS stimulants, at the recommended dosage, may cause psychotic or manic symptoms (e.g., hallucinations, delusional thinking, or mania) in patients without a prior history of psychotic illness or mania. In a pooled analysis of multiple short-term, placebo-controlled studies of CNS stimulants, psychotic or manic symptoms occurred in approximately 0.1% of CNS stimulant-treated patients compared to 0% of placebo-treated patients. If such symptoms occur, consider discontinuing XELSTRYM.

5.5 Long-Term Suppression of Growth in Pediatric Patients XELSTRYM is not approved for use and is not recommended in pediatric patients below 6 years of age <span class="opacity-50 text-xs">[see Use in Specific Populations (8.4) ]</span>. CNS stimulants have been associated with weight loss and slowing of growth rate in pediatric patients. Closely monitor growth (weight and height) in XELSTRYM-treated pediatric patients treated with CNS stimulants, including XELSTRYM. In a 7-week trial with a dose-optimization phase and a placebo-controlled phase of XELSTRYM in pediatric patients 6 to 17 years old with ADHD, there was a mean decrease in weight while taking XELSTRYM. Additionally, in studies of another CNS stimulant, there was slowing of the increase in height <span class="opacity-50 text-xs">[see ADVERSE REACTIONS (6.1) ]</span> . Pediatric patients not growing or gaining height or weight as expected may need to have their treatment interrupted. XELSTRYM is not approved for use in pediatric patients below 6 years of age <span class="opacity-50 text-xs">[see USE IN SPECIFIC POPULATIONS (8.4) ]</span> .

5.6 Peripheral Vasculopathy, including Raynaud’s Phenomenon CNS stimulants, including XELSTRYM, used to treat ADHD are associated with peripheral vasculopathy, including Raynaud&apos;s phenomenon. Signs and symptoms are usually intermittent and mild; however, sequelae have included digital ulceration and/or soft tissue breakdown. Effects of peripheral vasculopathy, including Raynaud&apos;s phenomenon, were observed in post-marketing reports and at the therapeutic dosage of CNS stimulants in all age groups throughout the course of treatment. Signs and symptoms generally improved after dosage reduction or discontinuation of the CNS stimulant. Careful observation for digital changes is necessary during XELSTRYM treatment. Further clinical evaluation (e.g., rheumatology referral) may be appropriate for XELSTRYM-treated patients who develop signs or symptoms of peripheral vasculopathy.

5.7 Serotonin Syndrome Serotonin syndrome, a potentially life-threatening reaction, may occur when amphetamines are used in combination with other drugs that affect the serotonergic neurotransmitter systems such as monoamine oxidase inhibitors (MAOIs), selective serotonin reuptake inhibitors (SSRIs), serotonin norepinephrine reuptake inhibitors (SNRIs), triptans, tricyclic antidepressants, fentanyl, lithium, tramadol, tryptophan, buspirone, and St. John&apos;s Wort <span class="opacity-50 text-xs">[see DRUG INTERACTIONS (7.1) ]</span> . The co-administration with cytochrome P450 2D6 (CYP2D6) inhibitors may also increase the risk with increased exposure to XELSTRYM. In these situations, consider an alternative non-serotonergic drug or an alternative drug that does not inhibit CYP2D6 <span class="opacity-50 text-xs">[see DRUG INTERACTIONS (7.1) ]</span> . Serotonin syndrome symptoms may include mental status changes (e.g., agitation, hallucinations, delirium, and coma), autonomic instability (e.g., tachycardia, labile blood pressure, dizziness, diaphoresis, flushing, hyperthermia), neuromuscular symptoms (e.g., tremor, rigidity, myoclonus, hyperreflexia, incoordination), seizures, and/or gastrointestinal symptoms (e.g., nausea, vomiting, diarrhea). Concomitant use of XELSTRYM with MAOI drugs is contraindicated <span class="opacity-50 text-xs">[see CONTRAINDICATIONS (4) ]</span> . Discontinue treatment with XELSTRYM and any concomitant serotonergic agents immediately if symptoms of serotonin syndrome occur, and initiate supportive symptomatic treatment. If concomitant use of XELSTRYM with other serotonergic drugs or CYP2D6 inhibitors is clinically warranted, initiate XELSTRYM with lower doses, monitoring patients for the emergence of serotonin syndrome during drug initiation or titration, and inform patients of the increased risk for serotonin syndrome.

5.8 Contact Sensitization Use of XELSTRYM may lead to contact sensitization (allergic contact dermatitis). Erythema is commonly seen with use of XELSTRYM and is not by itself an indication of sensitization. However, contact sensitization should be suspected if erythema is accompanied by evidence of a more intense local reaction (edema, papules, vesicles) that does not significantly improve within 48 hours or spreads beyond the application site. Confirmation of a diagnosis of contact sensitization may require further diagnostic testing <span class="opacity-50 text-xs">[see CONTRAINDICATION (4) ]</span> . Manifestations of systemic sensitization may include a flare-up of previous dermatitis or of prior positive patch-test sites, or generalized skin eruptions in previously unaffected skin. Other systemic reactions may include headache, fever, malaise, arthralgia, diarrhea, or vomiting. No cases of systemic sensitization have been observed in clinical trials of XELSTRYM. Patients who develop contact sensitization to XELSTRYM and require oral treatment with amphetamine should be initiated on oral medication under close medical supervision. Discontinue XELSTRYM if contact sensitization is suspected. It is possible that some patients sensitized to amphetamine by exposure to XELSTRYM may not be able to take amphetamine in any form.

5.9 Application Site Reactions Local skin reactions, such as pain, pruritus, burning sensation, erythema, discomfort, edema, and/or swelling were reported during the wear time or immediately after removal of XELSTRYM <span class="opacity-50 text-xs">[see ADVERSE REACTIONS (6.1) ]</span> . Patients who experienced discomfort and/or pain during the wear time reported resolution within 2 to 4 hours after application. The potential for application site reactions and increased skin irritation, discomfort or pain may occur with XELSTRYM if the same application site is used repeatedly. Patients should select a different application site each day to minimize skin reactions.

5.10 Use of External Heat When heat is applied to XELSTRYM after application, both the rate and extent of absorption are increased. After application of a heating pad, amphetamine exposure (AUC 0-9h ) was about 1.5-times greater than without heating pad application <span class="opacity-50 text-xs">[see CLINICAL PHARMACOLOGY (12.3) ]</span>. Advise patients to avoid exposing XELSTRYM to direct external heat sources such as hair dryers, heating pads, electric blankets, heated water beds, etc., while wearing XELSTRYM.

5.11 Motor and Verbal Tics, and Worsening of Tourette’s Syndrome CNS stimulants, including amphetamine, have been associated with the onset or exacerbation of motor and verbal tics. Worsening of Tourette’s syndrome has also been reported <span class="opacity-50 text-xs">[see ADVERSE REACTIONS (6.2) ]</span> . Before initiating XELSTRYM, assess the family history and clinically evaluate patients for tics or Tourette’s syndrome. Regularly monitor XELSTRYM-treated patients for the emergence or worsening of tics or Tourette’s syndrome, and discontinue treatment if clinically appropriate.