MYDAYIS
Clinical safety rating: caution
Comprehensive clinical and safety monograph for MYDAYIS (MYDAYIS).
MYDAYIS is a fixed-dose combination of amphetamine and dextroamphetamine, which are non-catecholamine sympathomimetic amines with CNS stimulant activity. The mechanism of action in ADHD is not fully elucidated, but they block the reuptake of norepinephrine and dopamine into the presynaptic neuron and increase their release into the extraneuronal space.
| Metabolism | Amphetamine and dextroamphetamine are extensively metabolized by the liver via oxidative deamination, aromatic hydroxylation, and oxidative N-dealkylation, primarily by CYP2D6 and to a lesser extent by other CYP enzymes. The major metabolites include 4-hydroxyamphetamine, norephedrine, and 4-hydroxynorephedrine. |
| Excretion | Renal (approx. 90% as unchanged drug and 10% as inactive metabolites); fecal <5% |
| Half-life | 12 hours for d-methylphenidate; 3-4 hours for l-methylphenidate; clinical context: d-isomer provides extended coverage; l-isomer contributes minimal activity |
| Protein binding | d-methylphenidate: ~58% bound to albumin; l-methylphenidate: ~46% bound to albumin |
| Volume of Distribution | d-methylphenidate: 1.8 L/kg; l-methylphenidate: 1.6 L/kg; clinical meaning: high tissue distribution |
| Bioavailability | Oral: 22-25% due to first-pass metabolism (d-methylphenidate); l-methylphenidate: lower due to extensive presystemic metabolism |
| Onset of Action | Oral: 1-2 hours (peak effect at 4-5 hours for d-methylphenidate); immediate-release component: 30-60 minutes |
| Duration of Action | 12-14 hours; clinical notes: biphasic release profile with immediate-release and extended-release components; suitable for once-daily dosing |
| Molecular Weight | 303.4 |
Oral, 12.5 mg or 25 mg once daily in the morning.
| Dosage form | CAPSULE, EXTENDED RELEASE |
| Renal impairment | GFR 30-89 mL/min: No adjustment. GFR 15-29 mL/min: Maximum 25 mg once daily. GFR <15 mL/min or dialysis: Not recommended. |
| Liver impairment | Child-Pugh A: No adjustment. Child-Pugh B: Maximum 12.5 mg once daily. Child-Pugh C: Not recommended. |
| Pediatric use | Ages 13-17: Same as adult. Not approved for children <13 years. |
| Geriatric use | No specific adjustment; monitor for insomnia, agitation, and cardiovascular effects. Start at lowest dose (12.5 mg) due to potential increased sensitivity. |
| 1st trimester | Contraindicated due to risk of fetal cardiovascular and central nervous system malformations. |
| 2nd trimester | Contraindicated due to risk of fetal cardiovascular and central nervous system malformations. |
| 3rd trimester | Contraindicated due to risk of neonatal persistent pulmonary hypertension and withdrawal symptoms. |
Clinical note
Comprehensive clinical and safety monograph for MYDAYIS (MYDAYIS).
| Placental transfer | Crosses placenta; based on animal studies and human placental perfusion models. |
| Breastfeeding | Excreted into breast milk; potential for adverse effects in infant including agitation, insomnia, and decreased weight gain. Use with caution or avoid. |
| Lactation Rating |
■ FDA Black Box Warning
WARNING: ABUSE AND DEPENDENCE. CNS stimulants, including MYDAYIS, have a high potential for abuse and dependence. Assess the risk of abuse prior to prescribing and monitor for signs of abuse and dependence while on therapy.
| Serious Effects |
PregnancyHypertensionGlaucomaHistory of drug abuseConcurrent MAOI useHypersensitivity to amphetamines
| Precautions | Serious cardiovascular events: sudden death, stroke, myocardial infarction in patients with pre-existing cardiac abnormalities, Blood pressure and heart rate increase, Psychiatric adverse events: exacerbation of pre-existing psychosis, mania, aggressive behavior, Long-term suppression of growth in children, Seizures: may lower seizure threshold, Peripheral vasculopathy, including Raynaud's phenomenon, Serotonin syndrome, particularly with concomitant serotonergic drugs, Visual disturbance: difficulty with accommodation, Potential for abuse and dependence |
| Food/Dietary | High-fat meals may delay the absorption of MYDAYIS; avoid consumption of high-fat foods within 30 minutes before and after taking the dose. Grapefruit juice has not been studied but is not expected to interact meaningfully; however, caution is advised due to potential CYP3A4 interactions with other methylphenidate formulations. Alcohol may increase the rate of dexmethylphenidate release; avoid alcohol consumption. |
Loading safety data…
| L4 - Possibly Hazardous |
| Teratogenic Risk | MYDAYIS (dextroamphetamine/amphetamine) is FDA Pregnancy Category C. First trimester: increased risk of major congenital malformations, particularly gastroschisis, oral clefts, and cardiac anomalies based on epidemiological data. Second and third trimesters: risk of premature delivery, low birth weight, and neonatal withdrawal symptoms including dysphoria, agitation, and feeding difficulties. Use only if potential benefit justifies risk. |
| Fetal Monitoring | Monitor maternal blood pressure, heart rate, and weight gain. Assess for signs of abuse or dependency. Fetal monitoring: ultrasound for growth and anatomy; consider fetal echocardiogram if first-trimester exposure. Neonatal monitoring: observe for withdrawal symptoms (irritability, jitteriness, poor feeding) for 48-72 hours after delivery. |
| Fertility Effects | No well-controlled studies on fertility. Amphetamines may suppress spermatogenesis and reduce sperm motility in males based on animal studies. In females, may cause menstrual irregularities and anovulation due to appetite suppression and weight loss. Limited human data suggest possible reversible impairment of fertility. |
| Clinical Pearls | MYDAYIS contains serdexmethylphenidate and dexmethylphenidate, providing a dual-release mechanism that includes both immediate and delayed release. Avoid use in patients with known hypersensitivity to methylphenidate or other components. Contraindicated in patients with glaucoma, motor tics, or a family history of Tourette's syndrome. Monitor for hypertension, tachycardia, and growth suppression in children. Do not administer within 48 hours of surgery where vasopressors are used. Use caution in patients with a history of substance abuse. |
| Patient Advice | Take exactly as prescribed; do not crush, chew, or split the capsule. · Swallow whole; if unable to swallow, may open capsule and sprinkle entire contents onto a tablespoon of applesauce, consume immediately without chewing. · Avoid taking with or within 30 minutes of high-fat meals to prevent delayed absorption. · Do not take afternoon or evening doses close to bedtime to avoid insomnia. · Store at room temperature, protect from moisture and light. · Report any signs of cardiac symptoms (chest pain, palpitations, shortness of breath) or psychiatric symptoms (aggression, hallucinations) to your healthcare provider. · This drug has a high potential for abuse; keep in a safe place and do not share with others. |