Vyvanse Seasonal Use Considerations: A Clinical Guide to Lisdexamfetamine Year-Round

Does the season change how lisdexamfetamine works?

Vyvanse is an inactive prodrug: after a capsule is swallowed, lisdexamfetamine is converted to dextroamphetamine and l-lysine mainly in the blood by red blood cells, not by cytochrome P450 enzymes [1]. In a laboratory school study of 117 children aged 6 to 12, lisdexamfetamine 30 to 70 mg beat placebo at every time point from 1.5 to 13 hours (P < .005) [2].

Label dosing and morning timing

The Vyvanse label specifies morning dosing with or without food and says to avoid afternoon doses because of the potential for insomnia [1]. ADHD treatment starts at 30 mg once daily and is adjusted by 10 or 20 mg at roughly weekly intervals to a maximum of 70 mg a day; adult binge eating disorder starts at 30 mg and rises by 20 mg at roughly weekly intervals to 50 to 70 mg a day [1]. A capsule may be swallowed whole or opened and mixed with yogurt, water or orange juice and consumed immediately, and the label says a single dose should not be divided [1].

Heart rate and blood pressure

Stimulants raise blood pressure by a mean of about 2 to 4 mm Hg and heart rate by about 3 to 6 beats per minute, and the label asks for blood pressure and pulse monitoring in everyone treated [1]. In the two 12-week binge eating disorder trials, mean pulse rose 4.41 to 6.31 beats per minute [5]. The label says to avoid Vyvanse in known structural cardiac abnormalities, cardiomyopathy, serious arrhythmia, coronary artery disease or other serious cardiac disease, and notes that sudden death has been reported in such patients given stimulants at ADHD doses [1].

Supplements and drugs that change amphetamine levels

Ascorbic acid is a urinary acidifying agent that lowers amphetamine blood levels and efficacy; the label says to increase the dose based on clinical response. Sodium bicarbonate is an alkalinizing agent that raises amphetamine blood levels and potentiates the action of amphetamine, so the label says coadministration should be avoided [1].

The Vyvanse label lists use with an MAOI, or within 14 days after stopping one, as a contraindication because of the risk of hypertensive crisis [1]. Other serotonergic drugs, including SSRIs, SNRIs, triptans, tricyclic antidepressants, tramadol and St. John's wort, can increase the risk of serotonin syndrome, and the label calls for starting with lower doses and monitoring, particularly at initiation or after a dose increase [1].

Year-round monitoring in children

In a 4-week trial in children aged 6 to 12, weight fell by a mean of 0.9, 1.9 and 2.5 pounds at 30, 50 and 70 mg, against weight gain on placebo. The label calls for close monitoring of height and weight, and says children who are not growing or gaining weight as expected may need a treatment interruption [1].