QUILLICHEW ER
Clinical safety rating: caution
Comprehensive clinical and safety monograph for QUILLICHEW ER (QUILLICHEW ER).
Quillichew ER contains methylphenidate, a central nervous system (CNS) stimulant. The mechanism of action in ADHD is not fully understood, but it is thought to block the reuptake of norepinephrine and dopamine into the presynaptic neuron, increasing their availability in the extraneuronal space.
| Metabolism | Methylphenidate is primarily metabolized by deesterification via carboxylesterase 1 (CES1) to ritalinic acid, which is pharmacologically inactive. Minor metabolism via hydroxylation and microsomal oxidation. |
| Excretion | QuilliChew ER (methylphenidate extended-release chewable tablet) is primarily eliminated via renal excretion as metabolites (60-80%) and unchanged drug (approx. 10%). Hepatic metabolism accounts for the remainder. Fecal elimination is minimal. |
| Half-life | The terminal elimination half-life of methylphenidate is approximately 3-4 hours in children and 3.5-5 hours in adults. For QuilliChew ER, the extended-release formulation provides a prolonged absorption phase, with an effective duration of action of up to 12 hours. |
| Protein binding | Methylphenidate is approximately 10-33% bound to plasma proteins, primarily albumin. Binding is low and not clinically significant. |
| Volume of Distribution | Volume of distribution (Vd) for methylphenidate is approximately 2-3 L/kg, indicating extensive tissue distribution. It is not highly bound to tissues. |
| Bioavailability | Oral bioavailability of methylphenidate is variable and low, approximately 11-52% due to extensive first-pass metabolism. QuilliChew ER is designed to deliver a consistent extended-release profile with a bioavailability of about 20-30% relative to immediate-release formulations. |
| Onset of Action | Onset of action after oral administration of QuilliChew ER occurs within 45-60 minutes, with peak plasma concentrations reached in approximately 5 hours (range 4-7 hours). |
| Duration of Action | Duration of action is up to 12 hours following a single dose, due to the extended-release formulation. Clinical effects are sustained throughout the day, supporting once-daily dosing. |
| Molecular Weight | 269.3 |
Initial 20 mg orally once daily, titrate by 10 mg weekly to maximum 60 mg/day (methylphenidate component).
| Dosage form | TABLET, EXTENDED RELEASE, CHEWABLE |
| Renal impairment | No dosage adjustment recommended for GFR >30 mL/min; avoid in GFR ≤30 mL/min. |
| Liver impairment | Child-Pugh Class A: no adjustment; Child-Pugh Class B: reduce dose by 50%; Child-Pugh Class C: not recommended. |
| Pediatric use | Children ≥6 years: initial 20 mg orally once daily, titrate by 10 mg weekly to max 60 mg/day. |
| Geriatric use | Start at 10 mg orally once daily, titrate cautiously; monitor for increased sensitivity and cardiovascular effects. |
| 1st trimester | Methylphenidate is pregnancy category C; may increase risk of cardiac malformations. Use only if benefit outweighs risk. |
| 2nd trimester | Limited data; consider potential for reduced fetal growth and preterm delivery. Monitor fetal growth. |
| 3rd trimester | Use near term may cause neonatal withdrawal (jitteriness, feeding problems). Avoid if possible. |
Clinical note
Comprehensive clinical and safety monograph for QUILLICHEW ER (QUILLICHEW ER).
| Placental transfer | Methylphenidate crosses the placenta; cord blood concentrations approximately 0.3-1.0 times maternal plasma levels. |
| Breastfeeding | Methylphenidate is excreted into breast milk in low concentrations; relative infant dose estimated 0.2-0.7%. Monitor infant for irritability, poor feeding, and insomnia. Consider lowest effective maternal dose. |
■ FDA Black Box Warning
QUILLICHEW ER has a high potential for abuse and dependence. Prolonged use may lead to drug dependence. Misuse may cause sudden death or serious cardiovascular adverse events.
| Serious Effects |
Hypersensitivity to methylphenidateMarked anxiety, tension, or agitationGlaucomaMotor tics or family history of Tourette syndromeConcomitant MAOI therapy or within 14 days
| Precautions | Serious cardiovascular events: sudden death, stroke, myocardial infarction in patients with pre-existing structural cardiac abnormalities or other serious heart problems., Blood pressure and heart rate increase; monitor closely., Psychiatric adverse events: exacerbation of pre-existing psychosis, mania, or aggressive behavior., Long-term suppression of growth (weight and height) in pediatric patients., Seizures: use with caution in patients with history of seizures., Priapism: prolonged, painful erections may occur., Peripheral vasculopathy: Raynaud's phenomenon. |
| Food/Dietary | Avoid high-fat meals as they may delay absorption and alter peak concentration. Grapefruit and grapefruit juice may increase methylphenidate levels and should be avoided. Acidic foods (e.g., citrus fruits, colas) can affect drug absorption; maintain a consistent dietary pattern. Alcohol may cause dose dumping and should be avoided. |
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| Lactation Rating | L3 (Moderately Safe) |
| Teratogenic Risk | Pregnancy Category C. First trimester: Possible increased risk of cardiovascular malformations and oral clefts from methylphenidate exposure; however, absolute risk remains low. Second and third trimesters: Risk of preterm birth, low birth weight, and neonatal withdrawal syndrome (including irritability, dysphoria, and poor feeding). |
| Fetal Monitoring | Maternal: Blood pressure, heart rate, weight gain, and signs of anorexia or insomnia. Fetal: Growth assessment via ultrasound (every 4-6 weeks in third trimester) and fetal heart rate monitoring. Neonatal: Monitor for withdrawal symptoms and birth weight. |
| Fertility Effects | No known direct effects on fertility in humans. Animal studies show no impairment of fertility at clinically relevant doses. Theoretical concern for hypothalamic-pituitary-gonadal axis disruption due to appetite suppression, but clinical significance uncertain. |
| Clinical Pearls | QUILLICHEW ER is an extended-release formulation of methylphenidate, a CNS stimulant, indicated for ADHD. Chewing or crushing the tablet destroys the extended-release mechanism, risking dose dumping. The tablet shell may appear in stool but is not medically significant. Monitor for growth suppression in children, weight loss, and potential for abuse. Avoid use in patients with glaucoma, motor tics, or family history of Tourette's syndrome. Use caution in patients with hypertension, tachycardia, or pre-existing psychiatric disorders like bipolar disorder or psychosis. Assess for potential drug interactions, particularly with MAOIs, anticoagulants (may decrease effect), and vasopressors. |
| Patient Advice | Take exactly as prescribed. Do not chew, crush, or split the tablet; swallow whole with liquid. · The tablet shell may appear in your stool, but the medication is absorbed; this is normal. · Do not take in the evening to prevent insomnia. Take in the morning with or without food. · Avoid alcohol while taking this medication; alcohol can affect the extended-release properties. · Common side effects include decreased appetite, trouble sleeping, dry mouth, and headache. · Report any chest pain, shortness of breath, fainting, or severe dizziness immediately. · Store at room temperature, protect from moisture, and keep out of reach of children. · Your doctor will monitor your blood pressure, heart rate, and weight regularly. · Do not stop abruptly; tapering may be needed to avoid withdrawal or rebound depression. |