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Drug Metabolism and Disposition: the... Jan 2013Enantioselective hydrolysis of oral racemic methylphenidate (dl-MPH) by carboxylesterase 1 (CES1) limits the absolute bioavailability of the pharmacologically active... (Comparative Study)
Comparative Study
Enantioselective hydrolysis of oral racemic methylphenidate (dl-MPH) by carboxylesterase 1 (CES1) limits the absolute bioavailability of the pharmacologically active d-MPH isomer to approximately 30% and that of the inactive l-MPH to only 1-2%. Coadministration of dl-MPH with ethanol results in elevated d-MPH plasma concentrations accompanied by CES1-mediated enantioselective transesterification of l-MPH to l-ethylphenidate (EPH). The present study tested the hypothesis that administration of the pure isomer dexmethylphenidate (d-MPH) will overcome the influence of ethanol on d-MPH absorption by eliminating competitive CES1-mediated presystemic metabolism of l-MPH to l-EPH. Twenty-four healthy volunteers received dl-MPH (0.3 mg/kg) or d-MPH (0.15 mg/kg), with or without ethanol (0.6 g/kg). During the absorption phase of dl-MPH, concomitant ethanol significantly elevated d-MPH plasma concentrations (44-99%; P < 0.005). Furthermore, immediately following the ethanol drink the subjective effects of "high," "good," "like," "stimulated," and overall "effect" were significantly potentiated (P ≤ 0.01). Plasma l-EPH concentrations exceeded those of l-MPH. Ethanol combined with pure d-MPH did not elevate plasma d-MPH concentrations during the absorption phase, and the ethanol-induced potentiation of subjective effects was delayed relative to dl-MPH-ethanol. These findings are consistent with l-MPH competitively inhibiting presystemic CES1 metabolism of d-MPH. Ethanol increased the d-MPH area under the curve (AUC)(0-inf) by 21% following dl-MPH (P < 0.001) and 14% for d-MPH (P = 0.001). In men receiving d-MPH-ethanol, the d-MPH absorption partial AUC(0.5-2 hours) was 2.1 times greater and the time to maximum concentration (T(max)) occurred 1.1 hours earlier than in women, consistent with an increased rate of d-MPH absorption reducing hepatic extraction. More rapid absorption of d-MPH carries implications for increased abuse liability.
Topics: Adult; Area Under Curve; Carboxylesterase; Dexmethylphenidate Hydrochloride; Esterification; Ethanol; Female; Hemodynamics; Humans; Male; Methylphenidate; Stereoisomerism; Young Adult
PubMed: 23104969
DOI: 10.1124/dmd.112.048595 -
Journal of Pharmaceutical Sciences Dec 2014We review the pharmaceutical science of ethylphenidate (EPH) in the contexts of drug discovery, drug interactions, biomarker for dl-methylphenidate (MPH)-ethanol... (Review)
Review
We review the pharmaceutical science of ethylphenidate (EPH) in the contexts of drug discovery, drug interactions, biomarker for dl-methylphenidate (MPH)-ethanol exposure, potentiation of dl-MPH abuse liability, contemporary "designer drug," pertinence to the newer transdermal and chiral switch MPH formulations, as well as problematic internal standard. d-EPH selectively targets the dopamine transporter, whereas d-MPH exhibits equipotent actions at dopamine and norepinephrine transporters. This selectivity carries implications for the advancement of tailored attention-deficit/hyperactivity disorder (ADHD) pharmacotherapy in the era of genome-based diagnostics. Abuse of dl-MPH often involves ethanol coabuse. Carboxylesterase 1 enantioselectively transesterifies l-MPH with ethanol to yield l-EPH accompanied by significantly increased early exposure to d-MPH and rapid potentiation of euphoria. The pharmacokinetic component of this drug interaction can largely be avoided using dexmethylphenidate (dexMPH). This notwithstanding, maximal potentiated euphoria occurs following dexMPH-ethanol. C57BL/6 mice model dl-MPH-ethanol interactions: an otherwise depressive dose of ethanol synergistically increases dl-MPH stimulation; a substimulatory dose of dl-MPH potentiates a low, stimulatory dose of ethanol; ethanol elevates blood, brain, and urinary d-MPH concentrations while forming l-EPH. Integration of EPH preclinical neuropharmacology with clinical studies of MPH-ethanol interactions provides a translational approach toward advancement of ADHD personalized medicine and management of comorbid alcohol use disorder.
Topics: Animals; Biomarkers; Dopamine; Dopamine Agonists; Esterification; Ethanol; Humans; Methylphenidate
PubMed: 25303048
DOI: 10.1002/jps.24202 -
Journal of Child and Adolescent... Jun 2006The aim of this study was to assess changes in symptomatology of attention-deficit/ hyperactivity disorder (ADHD) with extended-release dexmethylphenidate (d-MPHER)... (Randomized Controlled Trial)
Randomized Controlled Trial
OBJECTIVE
The aim of this study was to assess changes in symptomatology of attention-deficit/ hyperactivity disorder (ADHD) with extended-release dexmethylphenidate (d-MPHER) versus placebo in a laboratory classroom setting.
METHODS
This double-blind, placebo-controlled, crossover study randomized 54 children 6-12 years of age, stabilized on methylphenidate 20-40 mg/day. Patients participated in a practice day, then received 5 days of treatment with d-MPH-ER 20 mg/day or placebo. After a 1-day wash-out, they returned to the classroom and received 1 dose of their assigned treatment. Evaluations occurred predose and at postdose hours 1, 2, 4, 6, 8, 9, 10, 11, and 12. Children were then crossed over to the alternate treatment, using identical protocol. Primary efficacy variable was the Swanson, Kotkin, Agler, M-Flynn, and Pelham rating scale (SKAMP)-Combined scores, and primary analysis time point was 1 hour postdose; secondary efficacy variables over 12 hours included SKAMP-Attention and -Deportment scores and written math test results. Safety was assessed by adverse event (AE) recording following each period. Vital signs were recorded at each visit; laboratory tests were conducted at screening and final visit.
RESULTS
D-MPH-ER 20 mg/day showed a significant advantage over placebo as early as 1 hour postdose on SKAMP-Combined scores (p < 0.001). When analyzing the entire sample of 54 children, d-MPH-ER maintained significant superiority over placebo from hours 1 through 12 (p-values ranged from < 0.001 to 0.046). D-MPH-ER was well tolerated, with no severe AEs reported.
CONCLUSIONS
D-MPH-ER is safe and effective and improves classroom attention, deportment, and performance in children with ADHD.
Topics: Aptitude Tests; Attention Deficit Disorder with Hyperactivity; Central Nervous System Stimulants; Child; Cross-Over Studies; Delayed-Action Preparations; Dexmethylphenidate Hydrochloride; Double-Blind Method; Female; Humans; Male; Mathematics; Methylphenidate; Psychiatric Status Rating Scales; Treatment Outcome
PubMed: 16768632
DOI: 10.1089/cap.2006.16.239 -
Psychopharmacology Bulletin 2008The purpose of this study was to compare the efficacy and safety of extended-release dexmethylphenidate (d-MPH-ER) to that of d,l-MPH-ER and placebo in children with... (Comparative Study)
Comparative Study Randomized Controlled Trial
Treatment of children with attention-deficit/hyperactivity disorder: results of a randomized, multicenter, double-blind, crossover study of extended-release dexmethylphenidate and D,L-methylphenidate and placebo in a laboratory classroom setting.
The purpose of this study was to compare the efficacy and safety of extended-release dexmethylphenidate (d-MPH-ER) to that of d,l-MPH-ER and placebo in children with attention-deficit/hyperactivity disorder (ADHD) in a laboratory classroom setting. This multicenter, double-blind, crossover study randomized 82 children, 6 to 12 years of age, stabilized on a total daily dose to the nearest equivalent of 40 to 60 mg of d,l-MPH or 20 or 30 mg/day of d-MPH. Patients participated in a screening day and practice day, and were randomized to 1 of 10 sequences of all five treatments in five separate periods. Treatments included d-MPH-ER (20 mg/day), d-MPH-ER (30 mg/day), d,l-MPH-ER (36 mg/day), d,l-MPH-ER (54 mg/day), and placebo. Primary efficacy was measured by the change from predose on the Swanson, Kotkin, Agler, M-Flynn, and Pelham (SKAMP) Rating Scale-Combined scores at 2-h postdose during the 12-h laboratory assessment (d-MPH-ER 20 mg/day vs. d,l-MPH-ER 36 mg/day). Adverse events were monitored throughout the study period. d-MPH-ER (20 mg/day) was significantly more effective than d,l-MPH-ER (36 mg/day) in the primary efficacy variable, change from predose to 2-h postdose in SKAMP-combined score. In general, d-MPH-ER had an earlier onset of action than d,l-MPH-ER, while d,l-MPH-ER had a stronger effect at 12-h postdose. No serious adverse events were reported. Treatment with either agent was associated with significant improvements in ADHD symptoms. d-MPH-ER and d,l-MPH-ER can be differentiated on what part of the day each is more effective.
Topics: Area Under Curve; Attention Deficit Disorder with Hyperactivity; Central Nervous System Stimulants; Child; Cross-Over Studies; Delayed-Action Preparations; Dexmethylphenidate Hydrochloride; Double-Blind Method; Female; Humans; Male; Methylphenidate; Placebos
PubMed: 18362868
DOI: No ID Found -
International Journal of Clinical... Dec 2007The d-isomer of methylphenidate (d-MPH) is the pharmacologically active part of the racemic mixture of methylphenidate (d,l-MPH), which has been used for decades in the... (Comparative Study)
Comparative Study Randomized Controlled Trial
Similar bioavailability of dexmethylphenidate extended (bimodal) release, dexmethyl-phenidate immediate release and racemic methylphenidate extended (bimodal) release formulations in man.
OBJECTIVE
The d-isomer of methylphenidate (d-MPH) is the pharmacologically active part of the racemic mixture of methylphenidate (d,l-MPH), which has been used for decades in the treatment of attention-deficit/hyperactivity disorder (ADHD). A modified release formulation with bimodal release for the pure d-enantiomer (Focalin XR) has been developed to enable a fast onset of action and a sustained activity for once-daily administration. It was intended to achieve a bimodal concentration-time profile as observed after administration of two immediate release Focalin tablets. The pharmacokinetics of this d-MPH bimodal release formulation were compared with a d-MPH immediate release formulation and a similar bimodal release formulation of d,l-MPH in healthy adult volunteers.
MATERIALS AND METHODS
25 volunteers received a single 20 mg dose of d-MPH bimodal release formulation, two 10 mg doses of a d-MPH immediate release formulation given 4 h apart and a single 40 mg dose of d,l-MPH bimodal release formulation (1 : 1 ratio for d : l enantiomers). The washout between treatments in this 3-way crossover study was 7 days.
RESULTS
All three formulations were well-tolerated at the doses tested. The d-MPH bimodal release formulation generated two distinct d-MPH plasma concentration peaks and both peak concentrations and the time to peak were similar to those of the d-MPH immediate release formulation given 4 h apart and the d,l-MPH bimodal release formulation. The three formulations had Cmax and AUC0-infinity values of 15.5 +/- 4.3 ng/ml and 119 +/- 41 ng x h/ml for bimodal release d-MPH, 17.9 +/- 5.3 ng/ml and 115 +/- 40 ng A h/ml for immediate release d-MPH, and 16.4 +/- 4.4 ng/ml and 122 +/- 36 ng x h/ml for d,l-MPH bimodal release, respectively.
CONCLUSIONS
In summary, the 20 mg extended (bimodal) release formulation of d-MPH (Focalin XR) demonstrated a bimodal concentration-time profile and was bioequivalent to two 10 mg doses of immediate release d-MPH (Focalin) and was bioequivalent to 40 mg extended (bimodal) release d,l-MPH (Ritalin LA).
Topics: Adult; Area Under Curve; Biological Availability; Central Nervous System Stimulants; Delayed-Action Preparations; Dexmethylphenidate Hydrochloride; Female; Humans; Isomerism; Male; Methylphenidate; Therapeutic Equivalency
PubMed: 18184535
DOI: 10.5414/cpp45662 -
Journal of Child and Adolescent... 2004This pilot study examined the efficacy and duration of the effect of dexmethylphenidate (d-MPH) given once-daily in subjects with attention deficit hyperactivity... (Clinical Trial)
Clinical Trial
BACKGROUND
This pilot study examined the efficacy and duration of the effect of dexmethylphenidate (d-MPH) given once-daily in subjects with attention deficit hyperactivity disorder (ADHD).
METHOD
Subjects aged 6-18 years (inclusive) with ADHD were enrolled in this 8-week, openlabel study. Outcome measures included the Conners'Teacher and Parent Rating Scales, the Attention Deficit Disorder Rating Scale (ADDRS), the Clinical Global Impression (CGI) Scale, and teacher and parent visual analog scales to estimate the duration of efficacy. d-MPH was initiated at a dose of 2.5 mg/day. The dose was flexible, based on response and tolerability, and could be increased in increments of 2.5 mg/day to a maximum daily dose of 30 mg/day.
RESULTS
Twenty-two subjects (mean age, 8.7 +/- 0.4 years) were treated. Significant improvements (p <0.0001) from baseline occurred in the Conners' Teacher and Parent Rating Scales after 8 weeks. Of the evaluated subjects, 85.7% (18 of 21) showed at least a 30% improvement from baseline on the Conners' Teacher Rating Scale, and 86.4% (19 of 22) of subjects showed at least a 30% improvement from baseline on the Conners' Parent Rating Scale. Most subjects demonstrated an improvement on the ADDRS and the CGI-Improvement (CGI-I) scale. Median duration of effect was estimated at 6.2 hours (teachers) and at 7.5 hours (parents). On average, patients gained 2.4 pounds over the course of the study.
CONCLUSIONS
A single daily dose of d-MPH was effective in controlling ADHD in children and was well tolerated. Future studies are needed to confirm these findings and to evaluate chronic dosing with d-MPH.
Topics: Attention Deficit Disorder with Hyperactivity; Central Nervous System Stimulants; Child; Dexmethylphenidate Hydrochloride; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Humans; Male; Methylphenidate; Pilot Projects; Prospective Studies; Psychiatric Status Rating Scales; Stereoisomerism; Treatment Outcome
PubMed: 15662147
DOI: 10.1089/cap.2004.14.555 -
Journal of Child and Adolescent... 2004d,l-threo-methylphenidate HCl (D,L-MPH) is the most common treatment of attention deficit hyperactivity disorder (ADHD). A previous report showed placebo-controlled... (Clinical Trial)
Clinical Trial Randomized Controlled Trial
OBJECTIVES
d,l-threo-methylphenidate HCl (D,L-MPH) is the most common treatment of attention deficit hyperactivity disorder (ADHD). A previous report showed placebo-controlled efficacy for the purified d-isomer (dexmethylphenidate hydrochloride, d-MPH, Focalin) with a 2:1 potency compared to dl, and suggested a 6-hour duration of action. This study complements that report by studying the effect of placebo-controlled discontinuation and retesting the duration of action.
METHODS
A 6-week, open-label titration of d-MPH (2.5-10 mg twice-a-day) was followed by a double-blind, placebo-controlled, 2-week withdrawal study of responders.
RESULTS
In the open titration, 82% of the 89 enrolled patients achieved a Clinical Global Impression-Improvement (CGI-I) rating of much or very much improved. Only 5 patients discontinued for adverse events. Seventy-five patients continued into the placebo-controlled discontinuation. For the randomly assigned d-MPH (n=35) and placebo (n=40) groups, mean ages, respectively, were 10.1 +/- 2.9 and 9.9 +/- 2.7 years, 86% and 78% were male, and 70.6% and 80.0% took the ceiling dose of 10 mg twice-daily, respectively. Each group had 80% combined type ADHD and 20% inattentive type. By the end of the 2-week, placebo-masked withdrawal, significantly more placebo patients (24 of 39) than d-MPH continuers (6 of 35) relapsed (61.5% versus 17.1%, p=0.001). Compared to d-MPH continuers, placebo patients deteriorated significantly more in the 2-week period on teacher ratings of the 18 ADHD symptoms rated 0-3 (p=0.028), the 3 p.m. and 6 p.m. parent ADHD symptom ratings (p=0.0026 and p=0.0381, respectively), and clinic (2-3 p.m.) and home (6 p.m.) Math Tests (p=0.024 and p<0.0001, respectively). The 6 p.m. scores replicated the significant effect at 6 hours reported in the previous study.
CONCLUSIONS
d-MPH is safe, tolerable, and effective, with a 6-hour duration of effect suggested by the significant difference from placebo at 6 hours on a double-blind discontinuation.
Topics: Adolescent; Attention Deficit Disorder with Hyperactivity; Central Nervous System Stimulants; Child; Dexmethylphenidate Hydrochloride; Dose-Response Relationship, Drug; Double-Blind Method; Drug Administration Schedule; Female; Humans; Male; Methylphenidate; Psychiatric Status Rating Scales; Stereoisomerism; Treatment Outcome; Withholding Treatment
PubMed: 15662146
DOI: 10.1089/cap.2004.14.542 -
Journal of Clinical Psychopharmacology Oct 2012The objective of this study was to evaluate the safety and efficacy of dexmethylphenidate extended-release (d-MPH-ER) 30 versus 20 mg in children with... (Comparative Study)
Comparative Study Randomized Controlled Trial
A randomized, double-blind study of 30 versus 20 mg dexmethylphenidate extended-release in children with attention-deficit/hyperactivity disorder: late-day symptom control.
The objective of this study was to evaluate the safety and efficacy of dexmethylphenidate extended-release (d-MPH-ER) 30 versus 20 mg in children with attention-deficit/hyperactivity disorder (ADHD) in a 12-hour laboratory classroom setting. In a randomized, double-blind, 3-period × 3-treatment, crossover study, children aged 6 to 12 years with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition-diagnosed ADHD previously stabilized on MPH (40-60 mg/d) or D-MPH (20-30 mg/day) [corrected] were randomized to receive D-MPH-ER 20 mg/day, 30 mg/day, [corrected] or placebo for 7 days each. Primary efficacy measurements were change in the average SKAMP-Combined [corrected] score from predose to 10, 11, and 12 hours postdose [Avg(10-12)] between 30 mg [corrected] and 20 mg D-MPH-ER. Safety was assessed by adverse events, (AEs), [corrected] vital sign monitoring, and ECGs. [corrected] A total of 165 children were randomized, and 162 included in the intent-to-treat analysis. Mean Avg (10-12) change from pre-dose [corrected] in SKAMP-Combined score was significantly greater for D-MPH-ER 30 mg (-4.47) compared with D-MPH-ER 20 mg (-2.02; P = 0.002). Most common adverse events (≥ 3% in any group) were decreased appetite (6.1%, 4.9%, and 0%), headache (4.3%, 4.3%, and 1.9%), abdominal pain (3.7%, 3.1%, and 3.1%), and tachycardia (1.2%, 3.1%, and 0.6%) for D-MPH-ER 30 mg, D-MPH-ER 20 mg, and placebo, respectively). Significantly greater improvement in ADHD symptoms was noted with D-MPH-ER 30 mg compared with D-MPH-ER 20 mg at hours 10 through 12. Tolerability was comparable between doses. Dexmethylphenidate extended-release 30-mg dose may provide further benefit to patients who do not maintain optimal symptom control later in the day with D-MPH-ER 20 mg.
Topics: Attention Deficit Disorder with Hyperactivity; Central Nervous System Stimulants; Child; Cross-Over Studies; Delayed-Action Preparations; Dexmethylphenidate Hydrochloride; Dose-Response Relationship, Drug; Double-Blind Method; Female; Humans; Male; Methylphenidate; Time Factors; Treatment Outcome
PubMed: 22926597
DOI: 10.1097/JCP.0b013e3182677825 -
European Neuropsychopharmacology : the... Oct 2015The attention-deficit/hyperactivity disorder (ADHD) treatment literature has been focused on onset-of-effect and short-term effect size, with little exploration of ADHD... (Review)
Review
The attention-deficit/hyperactivity disorder (ADHD) treatment literature has been focused on onset-of-effect and short-term effect size, with little exploration of ADHD symptoms upon medication discontinuation. The objective of this narrative review and analysis was to better understand the relapse of ADHD symptoms upon discontinuation of medication treatment in children, adolescents, and adults with ADHD who have responded to medication treatment and to explore differences among different medications in maintaining treatment response. Randomized withdrawal studies of dexmethylphenidate hydrochloride (d-MPH), methylphenidate modified-release (MPH-LA), lisdexamphetamine dimesylate (LDX), guanfacine extended-release (GXR), and atomoxetine (ATX) in both children/adolescents and adults with ADHD were reviewed. The percentage of relapse was significantly higher and the time-to-relapse significantly shorter with placebo compared to active treatment in patients who were previously stable on 5 weeks to 1 year of active treatment, suggesting clinically significant benefit with continued long-term pharmacotherapy. However, percentage of relapse at each time point studied after discontinuing stimulants and GXR appears substantially higher than observed when discontinuing ATX, suggesting longer maintenance of response after discontinuing ATX than after stimulants and GXR. Additionally, slope of relapse percentages over time appears to be more rapid with stimulants or GXR than with ATX. These differences in maintenance of response among ATX, GXR, and stimulants may reflect differences in mechanisms of action and persistence of the medication effect. Alternatively, they may be due to methodological differences, including study design and response/relapse definitions. Continued investigation is needed regarding factors that affect risk of symptom relapse upon discontinuation of pharmacotherapy.
Topics: Attention Deficit Disorder with Hyperactivity; Central Nervous System Stimulants; Humans; Recurrence; Withholding Treatment
PubMed: 26169574
DOI: 10.1016/j.euroneuro.2015.06.003 -
Journal of Child and Adolescent... Jun 2008This study compared the efficacy and safety of extended-release dexmethylphenidate (d-MPH-ER) 20 mg/day and 30 mg/day with extended-release racemic methylphenidate... (Comparative Study)
Comparative Study Randomized Controlled Trial
Efficacy and safety of extended-release dexmethylphenidate compared with d,l-methylphenidate and placebo in the treatment of children with attention-deficit/hyperactivity disorder: a 12-hour laboratory classroom study.
OBJECTIVE
This study compared the efficacy and safety of extended-release dexmethylphenidate (d-MPH-ER) 20 mg/day and 30 mg/day with extended-release racemic methylphenidate hydrochloride (d,l-MPH-ER) 36 mg/day and 54 mg/day, and placebo in children with attention-deficit/hyperactivity disorder (ADHD) in a laboratory classroom setting.
METHODS
This multicenter, double-blind, crossover study included children (N = 84) 6-12 years of age, stabilized on total daily doses of 40 mg to 60 mg d,l-MPH or 20 mg/day or 30 mg/day d-MPH who were randomized to different treatment sequences. Primary efficacy was measured by the change from pre-dose in Swanson, Kotkin, Agler, M-Flynn, and Pelham (SKAMP) Rating Scale-Combined scores at 2 hours post-dose (d-MPH-ER 20 mg/day versus d,l-MPH- ER 36 mg/day). Adverse events were monitored throughout the study period.
RESULTS
Mean change in SKAMP-Combined score at 2 hours post-dose was significantly larger for d-MPH-ER 20 mg/day versus d,l-MPH-ER 36 mg/day (p < 0.001). Both doses of d-MPH-ER had a more rapid onset and greater morning effect relative to d,l-MPH-ER while d,l-MPH-ER had a greater effect at the end of the 12-hour day. All active treatments provided a significant benefit over placebo at most time points to 12 hours post-dosing. Both treatments were well tolerated.
CONCLUSIONS
d-MPH-ER and d,l-MPH-ER improved ADHD symptoms and were well tolerated. While d-MPH-ER had a faster onset of action, d,l-MPH-ER retained greater effect at the end of the 12- hour classroom day.
Topics: Attention Deficit Disorder with Hyperactivity; Chemistry, Pharmaceutical; Child; Cross-Over Studies; Delayed-Action Preparations; Dexmethylphenidate Hydrochloride; Double-Blind Method; Drug Administration Schedule; Female; Headache; Humans; Male; Methylphenidate; Placebos; Schools; Social Environment; Time Factors; Treatment Outcome
PubMed: 18582179
DOI: 10.1089/cap.2007.0015