Mydayis

The FDA has approved Mydayis (mixed salts of a single-entity amphetamine product, by Shire) to treat attention deficit hyperactivity disorder (ADHD) in patients 13 years or older. The approval carries the limitation that, at the same dose, patients 12 years or younger experienced higher plasma exposure and higher rates of adverse reactions, primarily insomnia and decreased appetite, compared with patients 13 years or older.¹ The extended-release capsules consist of 3 different types of medication-releasing beads.² Mydayis is a Schedule II controlled substance.¹

PHARMACOLOGY AND PHARMACOKINETICS

Mydayis contains d-amphetamine and l-amphetamine salts in a 3:1 ratio. Amphetamines are noncatecholamine sympathomimetic amines that cause central nervous system (CNS) stimulant activity. The exact mechanism of amphetamines in the treatment of ADHD has not been established.¹

DOSAGE AND ADMINISTRATION

Mydayis should be taken once daily upon awakening. Patients should be advised to take it consistently either with or without food. The initial starting dose is 12.5 mg daily and may be titrated at 12.5 mg increases every week if needed, based on therapeutic response. The maximum daily dose is 25 mg daily for patients aged 13 to 17 years and 50 mg daily for patients 18 years or older. Patients with severe renal impairment require dose reduction, and the medication should not be used in patients with end-stage renal disease. Patients should be assessed for cardiac disease prior to initiating treatment. Mydayis should not be substituted for other amphetamine-containing products on a milligram-per-milligram basis.¹

CLINICAL TRIALS

The efficacy of Mydayis to treat ADHD was evaluated in 3 short-term trials in adults aged 18 to 55 years and 2 short-term trials in adolescents aged 13 to 17 years. All were randomized, double-blind, and placebo-controlled studies. Compared with placebo, Mydayis was found to improve ADHD symptoms, as measured by the ADHD Rating Scale or the Permanent Product Measure of Performance.¹

CONTRAINDICATIONS, WARNINGS, AND PRECAUTIONS

Mydayis carries a boxed warning regarding the high potential for abuse and dependence associated with CNS stimulants. According to the warning, patients should have their risk for abuse evaluated before beginning treatment with Mydayis and should be monitored during treatment for signs of abuse and dependence.

Treatment with Mydayis is contraindicated in patients with a known hypersensitivity to amphetamine products or other components of Mydayis and during concurrent use or within 14 days of treatment with monoamine oxidase inhibitors.

Mydayis should not be used in patients with known structural cardiac abnormalities, cardiomyopathy, serious heart arrhythmia, or coronary artery disease. CNS stimulants can increase blood pressure and heart rate. Treatment with CNS stimulants may cause psychotic or manic symptoms in patients without a history of psy- chotic illness or mania, as well as exacerbate symptoms in patients with preexisting psychosis. Patients should be assessed for bipolar disorder before beginning treatment. In pediatric patients, the use of CNS stimulants has been associated with weight loss and a slower growth rate. Mydayis and other ADHD stimulant treatments are associated with peripheral vasculopathy, including Raynaud’s phenomenon. Use of Mydayis may lower the seizure threshold. The risk of serotonin syndrome increases when amphetamines are given concomitantly with serotonergic agents and during situations of overdose. Mydayis should not be used during pregnancy or breast-feeding.

Substances that change gastrointestinal and urinary pH can affect urinary excretion and alter blood levels of amphetamine. Gastrointestinal and urinary acidifying agents decrease amphetamine blood levels, and alkalinizing agents increase them. Concurrent use with either agent may require the Mydayis dose to be adjusted accordingly.¹

The most common adverse effects in patients 13 years or older were insomnia, decreased appetite, decreased weight, irritability, and nausea. In adults, the most common adverse effects were insomnia, decreased appetite, decreased weight, dry mouth, increased heart rate, and anxiety.^1,2

Monica Holmberg, PharmD, BCPS, earned her PharmD at the University of Connecticut and completed an ambulatory care residency at the Phoenix VA Healthcare System. Her practice has also included pediatrics and inpatient mental health. She lives in Phoenix, Arizona.

References

1. Mydayis [prescribing information]. Lexington, MA: Shire US Inc; 2017. accessdata.fda.gov/drugsatfda_docs/label/2017/022063s000lbl.pdf. Accessed October 9, 2017.

2. U.S. FDA approves Mydayis (mixed salts of a single-entity amphetamine product)—a new once-daily option for ADHD symptom control in patients 13 years and older [news release]. Lexington, MA; Shire PLC; June 20, 2017. shire.com/en/newsroom/2017/june/w6x937. Accessed October 9, 2017.