Chemical formula: C₁₄H₁₉NO₂ Molecular mass: 233.306 g/mol PubChem compound: 154101
Dexmethylphenidate is the d-threo enantiomer of racemic methylphenidate. Published studies and postmarketing reports on methylphenidate use during pregnancy have not identified a drug-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes. There may be risks to the fetus associated with the use of CNS stimulants use during pregnancy (see Clinical Considerations). Embryo-fetal development studies in rats showed delayed fetal skeletal ossification at doses up to 5 times the maximum recommended human dose (MRHD) of 20 mg/day given to adults based on plasma levels. A decrease in pup weight in males was observed in a pre- and post-natal development study with oral administration of methylphenidate to rats throughout pregnancy and lactation at doses 5 times the MRHD of 20 mg/day given to adults based on plasma levels. Plasma levels in adults were comparatively similar to plasma levels in adolescents (see Data).
The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.
CNS stimulants, such as dexmethylphenidate, can cause vasoconstriction and thereby decrease placental perfusion. No fetal and/or neonatal adverse reactions have been reported with the use of therapeutic doses of methylphenidate during pregnancy; however, premature delivery and low birth weight infants have been reported in amphetamine-dependent mothers.
In embryo-fetal development studies conducted in rats and rabbits, dexmethylphenidate was administered orally at doses of up to 20 and 100 mg/kg/day, respectively, during the period of organogenesis. No evidence of malformations was found in either the rat or rabbit study; however, delayed fetal skeletal ossification was observed at the highest dose level in rats. When dexmethylphenidate was administered to rats throughout pregnancy and lactation at doses of up to 20 mg/kg/day, post-weaning body weight gain was decreased in male offspring at the highest dose, but no other effects on postnatal development were observed. At the highest doses tested, plasma levels [area under the curves (AUCs)] of dexmethylphenidate in pregnant rats and rabbits were approximately 5 and 1 times, respectively, those in adults dosed with the MRHD of 20 mg/day.
Racemic methylphenidate has been shown to cause malformations (increased incidence of fetal spina bifida) in rabbits when given in doses of 200 mg/kg/day throughout organogenesis.
Dexmethylphenidate is the d-threo enantiomer of racemic methylphenidate. Limited published literature, based on milk sampling from seven mothers reports that methylphenidate is present in human milk, which resulted in infant doses of 0.16% to 0.7% of the maternal weight-adjusted dosage and a milk/plasma ratio ranging between 1.1 and 2.7. There are no reports of adverse effects on the breastfed infant and no effects on milk production. Long-term neurodevelopmental effects on infants from stimulant exposure are unknown. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for dexmethylphenidate and any potential adverse effects on the breastfed infant from dexmethylphenidate or from the underlying maternal condition.
Monitor breastfeeding infants for adverse reactions, such as agitation, insomnia, anorexia, and reduced weight gain.
Lifetime carcinogenicity studies have not been carried out with dexmethylphenidate. In a lifetime carcinogenicity study carried out in B6C3F1 mice, racemic methylphenidate caused an increase in hepatocellular adenomas, and in males only, an increase in hepatoblastomas was seen at a daily dose of approximately 60 mg/kg/day. This dose is approximately 2 times the MRHD of 60 mg/day of racemic methylphenidate given to children on a mg/m² basis. Hepatoblastoma is a relatively rare rodent malignant tumor type. There was no increase in total malignant hepatic tumors. The mouse strain used is sensitive to the development of hepatic tumors and the significance of these results to humans is unknown. Racemic methylphenidate did not cause any increase in tumors in a lifetime carcinogenicity study carried out in F344 rats; the highest dose used was approximately 45 mg/kg/day, which is approximately 4 times the MRHD (children) of 60 mg/day of racemic methylphenidate on a mg/m² basis.
In a 24-week carcinogenicity study with racemic methylphenidate in the transgenic mouse strain p53+/-, which is sensitive to genotoxic carcinogens, there was no evidence of carcinogenicity. Male and female mice were fed diets containing the same concentrations as in the lifetime carcinogenicity study; the high-dose group was exposed to 60-74 mg/kg/day of racemic methylphenidate.
Dexmethylphenidate was not mutagenic in the in vitro Ames reverse mutation assay, in the in vitro mouse lymphoma cell forward mutation assay, or in the in vivo mouse bone marrow micronucleus test. In an in vitro assay using cultured Chinese Hamster Ovary cells treated with racemic methylphenidate, sister chromatid exchanges and chromosome aberrations were increased, indicative of a weak clastogenic response.
No human data on the effect of methylphenidate on fertility are available.
Fertility studies have not been conducted with dexmethylphenidate. Racemic methylphenidate did not impair fertility in male or female mice that were fed diets containing the drug in an 18-week continuous breeding study. The study was conducted at doses of up to 160 mg/kg/day, approximately 10 times the MRHD of 60 mg/day of racemic methylphenidate given adolescents on a mg/m² basis.
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.
The safety data in this section is based on data related to dexmethylphenidate exposure during the premarketing development program in a total of 696 participants in clinical trials (684 patients, 12 healthy adult subjects). These participants received dexmethylphenidate 5, 10, or 20 mg/day. The 684 ADHD patients (ages 6 to 17 years) were evaluated in 2 controlled clinical studies, 2 clinical pharmacology studies, and 2 open-label long-term safety studies.
Most Common Adverse Reactions (incidence of greater than or equal to 5% and at least twice placebo): abdominal pain, fever, anorexia, and nausea
Adverse Reactions Leading to Discontinuation: Overall, 50 of 684 (7.3%) pediatric patients treated with dexmethylphenidate experienced an adverse reaction that resulted in discontinuation. The most common reasons for discontinuation were twitching (described as motor or vocal tics), anorexia, insomnia, and tachycardia (approximately 1% each).
The table below enumerates adverse reactions for two, placebo-controlled, parallel group studies in pediatric patients with ADHD taking dexmethylphenidate doses of 5, 10, and 20 mg/day. The table includes only those reactions that occurred in patients treated with dexmethylphenidate for which the incidence was at least 5% and twice the incidence among placebo-treated patients.
Common Adverse Reactions in Pediatric Patients (6 to 17 years of age) with ADHD:
| System Organ Class | Adverse Reactions | Dexmethylphenidate (N=79) | Placebo (N=82) |
|---|---|---|---|
| Body as a Whole | Abdominal Pain | 15% | 6% |
| Fever | 5% | 1% | |
| Digestive System | Anorexia | 6% | 1% |
| Nausea | 9% | 1% |
Abbreviation: ADHD,Attention Deficit Hyperactivity Disorder.
The following additional adverse reactions have been identified during post approval use of dexmethylphenidate. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
Musculoskeletal: rhabdomyolysis
Immune System Disorders: hypersensitivity reactions, such as angioedema, anaphylactic reactions
The following adverse reactions associated with the use of all Ritalin and dexmethylphenidate formulations were identified in clinical trials, spontaneous reports, and literature. Because these reactions were reported voluntarily from a population of uncertain size, it is not always possible to estimate their frequency reliably or to establish a causal relationship to drug exposure.
Infections and Infestations: nasopharyngitis
Blood and the Lymphatic System Disorders: leukopenia, thrombocytopenia, anemia
Immune System Disorders: hypersensitivity reactions, including angioedema and anaphylaxis
Metabolism and Nutrition Disorders: decreased appetite, reduced weight gain, and suppression of growth during prolonged use in pediatric patients
Psychiatric Disorders: insomnia, anxiety, restlessness, agitation, psychosis (sometimes with visual and tactile hallucinations), depressed mood
Nervous System Disorders: headache, dizziness, tremor, dyskinesia, including choreoatheetoid movements, drowsiness, convulsions, cerebrovascular disorders (including vasculitis, cerebral hemorrhages and cerebrovascular accidents), serotonin syndrome in combination with serotonergic drugs
Eye Disorders: blurred vision, difficulties in visual accommodation
Cardiac Disorders: tachycardia, palpitations, increased blood pressure, arrhythmias, angina pectoris
Respiratory, Thoracic and Mediastinal Disorders: cough
Gastrointestinal Disorders: dry mouth, nausea, vomiting, abdominal pain, dyspepsia
Hepatobiliary Disorders: abnormal liver function, ranging from transaminase elevation to severe hepatic injury
Skin and Subcutaneous Tissue Disorders: hyperhidrosis, pruritus, urticaria, exfoliative dermatitis, scalp hair loss, erythema multiforme rash, thrombocytopenic purpura
Musculoskeletal and Connective Tissue Disorders: arthralgia, muscle cramps, rhabdomyolysis
Investigations: weight loss (adult ADHD patients)
The list below shows adverse reactions not listed with Ritalin and dexmethylphenidate formulations that have been reported with other methylphenidate products based on clinical trials data and post-marketing spontaneous reports.
Blood and Lymphatic Disorders: pancytopenia
Immune System Disorders: hypersensitivity reactions, such as auricular swelling
Psychiatric Disorders: affect lability, mania, disorientation, libido changes
Nervous System Disorders: migraine
Eye Disorders: diplopia, mydriasis
Cardiac Disorders: sudden cardiac death, myocardial infarction, bradycardia, extrasystole, supraventricular tachycardia, ventricular extrasystole
Vascular Disorders: peripheral coldness, Raynaud’s phenomenon
Respiratory, Thoracic and Mediastinal Disorders: pharyngolaryngeal pain, dyspnea
Gastrointestinal Disorders: diarrhea, constipation
Skin and Subcutaneous Tissue Disorders: angioneurotic edema, erythema, fixed drug eruption
Musculoskeletal, Connective Tissue and Bone Disorders: myalgia, muscle twitching
Renal and Urinary Disorders: hematuria
Reproductive System and Breast Disorders: gynecomastia
General disorders: fatigue
Urogenital disorders: priapism
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