Methylphenidate poisoning: An evidence-based consensus guideline for out-of-hospital management

Methylphenidate for attention-deficit/hyperactivity disorder in adults: a narrative review

RATIONALE

Psychostimulants, including methylphenidate (MPH), are the mainstay of pharmacotherapy for attention-deficit/hyperactivity disorder (ADHD) in adults. Even though MPH is the most commonly used medication for ADHD these days, there are relatively few resources available that provide comprehensive insight into the pharmacological and clinical features of the compound.

OBJECTIVE

The aim of this paper is to provide an up-to-date outline of the pharmacology and clinical utility of MPH for ADHD in adult patients.

METHODS

While conducting the narrative review, we applied structured search strategies covering the two major online databases (MEDLINE and Cochrane Central Register of Controlled Trials). In addition, we performed handsearching of reference lists of relevant papers.

RESULTS

Methylphenidate exhibits multimodal mechanism of action, working primarily as a dopamine and noradrenaline reuptake inhibitor. It also protects the dopaminergic system against the ongoing 'wearing off' (by securing a substantial reserve pool of the neurotransmitter, stored in the presynaptic vesicles). In placebo-controlled trials, MPH was shown to be moderately effective both against the core ADHD symptoms (standardized mean difference [SMD], 0.49; 95% confidence interval [CI], 0.35-0.64), and the accompanying emotion regulation deficits (SMD, 0.34; 95% CI, 0.23-0.45). The most common adverse events related to long-term treatment with MPH are decreased appetite (~ 20%), dry mouth (15%), heart palpitations (13%), gastrointestinal infections (~ 10%), and agitation/feeling restless (~ 10%).

CONCLUSIONS

There is substantial body of evidence to suggest that MPH is an effective and safe treatment option for adults with ADHD.

Poison-related visits in a pediatric emergency department: A retrospective analysis of patients who bypass poison control centers

INTRODUCTION

Poison control centers (PCC) are an effective means to prevent unnecessary emergency department (ED) visits associated with poisoning exposures. However, not all patients with poison exposures utilize the PCC. The purpose of this study was to identify unintentional pediatric poisoning exposures presenting to a large US children's hospital that could have been managed onsite (i.e., at home) if consultation with a PCC had occurred prior to the ED visit.

METHODS

Using ED encounters from a tertiary children's hospital, unintentional pharmaceutical, chemical, or fume exposures occurring between October 1, 2014 and September 30, 2015 were identified from ICD-9-CM billing codes. Two specialists in poison information reviewed the medical records of the identified patients who had no contact with the PCC and determined whether these encounters were preventable through PCC triage. Descriptive statistics examined the differences between the encounters. Data were analyzed in R v3.2.4 (Vienna, Austria) and SAS v9.4 (SAS Institute, Cary, NC).

RESULTS

In the total study population (n = 231), 98 (42.4%) were PCC triaged and 133 (57.6%) were caregiver self-referred to the ED. For those who self-referred, 62 (46.6%) patients would have been recommended to be managed onsite instead of presenting at the ED for medical care. Analgesics and household cleaning products were the most common pharmaceutical and chemical exposures, respectively.

CONCLUSIONS

Nearly half of ED visits for pediatric patients with unintentional poisoning exposures could have been avoided by contacting a PCC. Educational and self-efficacy-based interventions are needed to expand the public's use of PCC services.

Occupational Factors Causing Pain Among Nurses in Mainland China

BACKGROUND Pain is a common problem affecting the wellbeing of nurses. This study investigated physical pain of nurses and their pain self-management in mainland China. MATERIAL AND METHODS A total of 2458 full-time nurses working in 18 hospitals across mainland China were studied from May 2016 to July 2016, of which a total of 1269 nurses (51.63%) experienced pain during the duration of this study. RESULTS Of the nurses reporting pain, most had general chronic pain (936 cases, 73.8%). Many nurses also had moderate to severe pain (904 cases, 71.2%). Another type of pain that was common was back and lower-limb pain (740 cases, 58.3%). Of the diagnosable symptoms, lumbar spondylosis was the most prominent, with 258 cases (33.1%). Nearly 50% of the nurses reported that their lives and sleep had been disrupted by pain, and 33.9% of the subjects are unsatisfied with their level of self-management of pain. Only 13.4% said that they would seek formal medical attention after feeling pain. Multivariate logistical analysis showed that factors such as the level of the hospital, years of experience, and shift schedule have a strong correlation with the incidence of pain among nurses. CONCLUSIONS The main cause of pain among nurses in mainland China is occupational factors, and the current status of this problem is not satisfactory.

Methylphenidate clinically oral doses improved brain and heart glutathione redox status and evoked renal and cardiac tissue injury in rats

Methylphenidate (MPH) is a first-line stimulant drug to treat attention deficit hyperactivity disorder (ADHD). Overdiagnosis of ADHD and MPH abuse lead to serious concerns about the possible long-term adverse consequences of MPH in healthy children and adolescents. We aimed to evaluate MPH effects in adolescent male Wistar rats (postnatal day 40) using an oral dose scheme (2 daily MPH doses 5 mg/kg in a 5% sucrose solution, 5 h apart, for 7 days) that mimics the therapeutic doses given to human adolescents. Twenty-four hours after the last MPH administration, rats were sacrificed and brain areas [cerebellum, prefrontal cortex (PFC), hippocampus, and striatum], peripheral organs (liver, heart, and kidneys), and blood were collected for biochemical and histological analysis. MPH treatment did not alter rats' body temperature or weight, neither food or water intake throughout the experiment. The ratio of reduced glutathione/oxidized glutathione (GSH/GSSG) significantly increased in the PFC and hippocampus of MPH-treated rats, meanwhile protein carbonylation remained unchanged in the brain. In the heart, the GSH/GSSG ratio and GSH levels were significantly increased, with decreased GSSG, while histology revealed significant damage, namely interstitial edema, vascular congestion, and presence of a fibrin-like material in the interstitial space. In the kidneys, MPH treatment resulted in extensive necrotic areas with cellular disorganization and cell infiltration, and immunohistochemistry analysis revealed a marked activation of nuclear factor-ĸB. This study showed that clinically relevant oral MPH doses improve the GSH redox status in the brain and heart, but evoke heart and kidney tissue damage to adolescent rats.

Methylphenidate effects in the young brain: friend or foe?

Attention deficit hyperactivity disorder (ADHD) is one of the most prevalent neuropsychiatry disorders in children and adolescents, and methylphenidate (MPH) is a first-line stimulant drug available worldwide for its treatment. Despite the proven therapeutic efficacy, concerns have been raised regarding the possible consequences of chronic MPH exposure during childhood and adolescence. Disturbances in the neurodevelopment at these crucial stages are major concerns given the unknown future life consequences. This review is focused on the long-term adverse effects of MPH to the brain biochemistry. Reports conducted with young and/or adolescent animals and studies with humans are reviewed in the context of long-term consequences after early life-exposure. MPH pharmacokinetics is also reviewed as there are differences among laboratory animals and humans that may be relevant to extrapolate the findings. Studies reveal that exposure to MPH in laboratory animals during young and/or adolescent ages can impact the brain, but the outcomes are dependent on MPH dose, treatment period, and animal's age. Importantly, the female sex is largely overlooked in both animal and human studies. Unfortunately, human reports that evaluate adults following adolescent or child exposure to MPH are very scarce. In general, human data indicates that MPH is generally safe, although it can promote several brain changes in early ages. Even so, there is a lack of long course patient evaluation to clearly establish whether MPH-induced changes are friendly or foe to the brain and more human studies are needed to assess the adult brain changes that arise from early MPH treatment.

webPOISONCONTROL: can poison control be automated?

BACKGROUND

A free webPOISONCONTROL app allows the public to determine the appropriate triage of poison ingestions without calling poison control. If accepted and safe, this alternative expands access to reliable poison control services to those who prefer the Internet over the telephone. This study assesses feasibility, safety, and user-acceptance of automated online triage of asymptomatic, nonsuicidal poison ingestion cases.

METHODS

The user provides substance name, amount, age, and weight in an automated online tool or downloadable app, and is given a specific triage recommendation to stay home, go to the emergency department, or call poison control for further guidance. Safety was determined by assessing outcomes of consecutive home-triaged cases with follow-up and by confirming the correct application of algorithms. Case completion times and user perceptions of speed and ease of use were measures of user-acceptance.

RESULTS

Of 9256 cases, 73.3% were triaged to home, 2.1% to an emergency department, and 24.5% directed to call poison control. Children younger than 6 years were involved in 75.2% of cases. Automated follow-up was done in 31.2% of home-triaged cases; 82.3% of these had no effect. No major or fatal outcomes were reported. More than 91% of survey respondents found the tool quick and easy to use. Median case completion time was 4.1 minutes.

CONCLUSION

webPOISONCONTROL augments traditional poison control services by providing automated, accurate online access to case-specific triage and first aid guidance for poison ingestions. It is safe, quick, and easy to use.

Treatment of toxicity from amphetamines, related derivatives, and analogues: a systematic clinical review

BACKGROUND

Overdose of amphetamine, related derivatives, and analogues (ARDA) continues to be a serious worldwide health problem. Patients frequently present to the hospital and require treatment for agitation, psychosis, and hyperadrenegic symptoms leading to pathologic sequelae and mortality.

OBJECTIVE

To review the pharmacologic treatment of agitation, psychosis, and the hyperadrenergic state resulting from ARDA toxicity.

METHODS

MEDLINE, PsycINFO, and the Cochrane Library were searched from inception to September 2014. Articles on pharmacologic treatment of ARDA-induced agitation, psychosis, and hyperadrenergic symptoms were selected. Evidence was graded using Oxford CEBM. Treatment recommendations were compared to current ACCF/AHA guidelines.

RESULTS

The search resulted in 6082 articles with 81 eligible treatment involving 835 human subjects. There were 6 high-quality studies supporting the use of antipsychotics and benzodiazepines for control of agitation and psychosis. There were several case reports detailing the successful use of dexmedetomidine for this indication. There were 9 high-quality studies reporting the overall safety and efficacy of β-blockers for control of hypertension and tachycardia associated with ARDA. There were 3 high-quality studies of calcium channel blockers. There were 2 level I studies of α-blockers and a small number of case reports for nitric oxide-mediated vasodilators.

CONCLUSIONS

High-quality evidence for pharmacologic treatment of overdose from ARDA is limited but can help guide management of acute agitation, psychosis, tachycardia, and hypertension. The use of butyrophenone and later-generation antipsychotics, benzodiazepines, and β-blockers is recommended based on existing evidence. Future randomized prospective trials are needed to evaluate new agents and further define treatment of these patients.

Methylphenidate intoxications in children and adults: exposure circumstances and evidence-based dose threshold for pre-hospital triage

CONTEXT

Methylphenidate intoxications mostly have a relatively mild course, although serious complications can occur.

OBJECTIVE

We aimed to characterize methylphenidate exposures and reassess our current dose threshold for hospital referral (2 mg/kg).

METHODS

In a prospective follow-up study, we analysed 364 consecutive methylphenidate exposures that were reported to the Dutch Poisons Information Center. Patients and/or physicians were surveyed by telephone using standardized questionnaires. Three physicians independently scored the observed severity of the intoxication of each patient as 'no/mild' (observation at home) or 'moderate/severe' (hospital referral necessary).

RESULTS

Unintentional exposures (40%) mostly occurred at home involving the patients' own medication or those from a family member. Compared to unintentionally exposed patients, intentionally exposed patients were exposed to relatively high methylphenidate doses (3.1 vs 1.6 mg/kg), more often used immediate release methylphenidate formulations (62 vs 34%) and more frequently had concomitant exposures (71 vs 17%). Severe symptoms like convulsions or coma were reported only in patients with concomitant exposures. Following exposure to methylphenidate only (i.e. no concomitant exposures), the most commonly reported symptoms were dry mucosa, headache, agitation, sleepiness and tachycardia. Our results show that the reported methylphenidate dose is predictive of the observed severity of the intoxication and can therefore aid in pre-hospital triage.

CONCLUSION

We increased our current dose threshold for hospital referral from 2 to 3 mg/kg. In addition, we will refer patients at lower doses when clinical symptoms indicate the need for hospital referral. Application of this new dose threshold optimizes triage, thereby reducing unnecessary hospital referral and thus costs, without jeopardising patient safety.

Adverse reactions of Methylphenidate in children with attention deficit-hyperactivity disorder: Report from a referral center

Objective:

The aim of the current study was to determine various aspects of methylphenidate adverse reactions in children with attention deficit-hyperactivity disorder (ADHD) in Iran.

Methods:

During the 6 months period, all children under methylphenidate treatment alone or along with other agents attending a university-affiliated psychology clinic were screened regarding all subjective and objective adverse drug reactions (ADRs) of methylphenidate. Causality and seriousness of detected ADRs were assessed by relevant World Health Organization definitions. The Schumock and Thornton questionnaire was used to determine preventability of ADRs.

Findings:

Seventy-one patients including 25 girls and 46 boys with ADHD under methylphenidate treatment were enrolled within the study period. All (100%) ADHD children under methylphenidate treatment developed at least one ADR. Anorexia (74.3%), irritability (57.1%), and insomnia (47.2%) were the most frequent methylphenidate-related adverse reactions. Except for one, all other detected ADRs were determined to be mild. In addition, no ADR was considered to be preventable and serious.

Conclusion:

Our data suggested that although methylphenidate related adverse reactions were common in children with ADHD, but they were mainly mild and nonserious.

Dexmedetomidine in a child with methylphenidate intoxication

Methylphenidate intoxication, due to accidental ingestion, is a common occurrence in pediatrics. Symptoms of extreme agitation are typically controlled with benzodiazepines or barbiturates. There is, however, a legitimate risk of mechanical ventilation due to respiratory depression with increasing doses of benzodiazepines. The authors describe a case of 7-y-old girl with methylphenidate toxicity where dexmedetomidine was successfully used to manage agitation and cardiovascular stimulation without respiratory compromise.

Differential influences of ethanol on early exposure to racemic methylphenidate compared with dexmethylphenidate in humans

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.

Non-medical use of methylphenidate: a review

INTRODUCTION: Methylphenidate is a psychostimulant medication used for the treatment of attention deficit hyperactivity disorder and narcolepsy. However, it has also been used for non-medical purposes, e.g. to produce euphoria, to increase self-esteem, and to achieve the so-called neurocognitive enhancement, decreasing the feeling of tiredness and increasing focus and attention. OBJECTIVE: To describe, from theoretical and contextual points of view, the potential for abuse and non-medical use of methylphenidate. METHOD: The PubMed, SciELO and Cochrane databases were searched using the following keywords in Portuguese: metilfenidato, transtorno do déficit de atenção com hiperatividade, facilitadores dos processos cognitivos or agentes nootrópicos, and abuso de substâncias; and in English: methylphenidate, attention deficit disorder with hyperactivity, cognitive enhancement or nootropic agents, and substance abuse. Studies published between 1990 and 2010 were selected for review. RESULTS: Non-medical use of methylphenidate is a relevant topic that raises important ethical and scientific questions in several areas, e.g. pharmacological and neurobiological characteristics, evidence of methylphenidate use, forms of non-medical use of methylphenidate, mechanisms of action, and therapeutic application of methylphenidate. According to the review, methylphenidate can generally influence performance as a result of its stimulatory effect. Notwithstanding, evidence does not support the conclusion that it can enhance cognitive performance. CONCLUSION: Health professionals need to acquire expert knowledge and inform patients and their families on the methylphenidate potential for abuse when used with non-medical purposes.

Transdermal and oral dl-methylphenidate-ethanol interactions in C57BL/6J mice: transesterification to ethylphenidate and elevation of d-methylphenidate concentrations

We tested the hypothesis that C57BL/6J mice will model human metabolic interactions between dl-methylphenidate (MPH) and ethanol, placing an emphasis on the MPH transdermal system (MTS). Specifically, we asked: (1) will ethanol increase d-MPH biological concentrations, (2) will MTS facilitate the systemic bioavailability of l-MPH, and (3) will l-MPH enantioselectively interact with ethanol to yield l-ethylphenidate (l-EPH)? Mice were dosed with MTS (¼ of a 12.5 cm(2) patch on shaved skin) or a comparable oral dl-MPH dose (7.5 mg/kg), with or without ethanol (3.0 g/kg), and then placed in metabolic cages for 3 h. MPH and EPH isomer concentrations in blood, brain, and urine were analyzed by gas chromatographic-mass spectrometry monitoring of N-(S)-prolylpiperidyl fragments. As in humans, MTS greatly facilitated the absorption of l-MPH in this mouse strain. Similarly, ethanol led to the enantioselective formation of l-EPH and to an elevation in d-MPH concentrations with both MTS and oral MPH. Although only guarded comparisons between MTS and oral MPH can be made due to route-dependent drug absorption rate differences, MTS was associated with significant MPH-ethanol interactions. Ethanol-mediated increases in circulating concentrations of d-MPH carry toxicological and abuse liability implications should this animal model hold for ethanol-consuming attention-deficit hyperactivity disorder patients or coabusers.

Case report: intoxication with high dose of long-acting methylphenidate (Concerta(®)) in a suicidal 14-year-old girl

A 14-year-old girl with suicidal ideation was presented to the paediatric hospital about 2 h after ingestion of 21 long-acting methylphenidate (MPH) 54-mg tablets (1,134 mg Concerta(®)). At admission signs of sympathomimetic syndrome were observed like agitation, visual hallucinations, slight hypertension, and sinus tachycardia. Treatment included prevention of absorption (30 g activated charcoal orally) and careful observation related to the overstimulation of the sympathic system. Despite the intake of charcoal, the serum concentrations of MPH were 107 and 93 ng/ml 2.5 and 22 h after ingestion of MPH tablets. No support of vital functions was necessary. The girl made a full recovery and was discharged after 3 days of care at the paediatric clinic and referred to the child and adolescent psychiatric department. Exposure to a huge overdose of long-acting MPH exhibited acute sympathomimetic toxicity but no life-threatening symptoms in this patient. Thus this case report suggests that patients intoxicated with high dose long-acting MPH formulations can recover without sequelae when managed properly.

Electrocardiographic effects of methylphenidate overdose

OBJECTIVES

Stimulants used in the management of attention-deficit hyperactivity disorder have been associated with an increased risk of sudden cardiac death. One mechanism could involve drug-induced repolarization delay, reflected as prolongation of the QT interval on the electrocardiogram, which has been described in some recipients of methylphenidate in therapeutic doses. Because QT prolongation is usually dose-related, this study was performed to investigate effects of methylphenidate overdose on the QT interval.

METHODS

Adults with methylphenidate overdose identified retrospectively were matched for sex and heart rate with a control subject with overdose of a noncardiotoxic substance, mainly acetaminophen. Notes were reviewed for clinical details and coingestants. Admission 12-lead electrocardiograms were individually calibrated and analyzed using a manual digitizer in a blinded manner by a single investigator. Mean QRS and QT intervals were calculated and differences between groups were analyzed.

RESULTS

Twenty-three cases of methylphenidate overdose (median reported dose 120 mg, range 40-1,500 mg) were identified (10 males, 13 females, mean age 27.8 years). There were multiple coingestants. Level of consciousness and mean hemodynamic variables were within normal limits for all cases. Symptoms recorded in cases included anxiety (32%), dilated pupils (20%), abdominal pain (16%), vomiting (12%), palpitations (12%), and chest pain (8%). No arrhythmias were recorded. Mean heart rate was 92.4/min in methylphenidate cases and 93.8/min in the heart rate-matched controls. There were no significant differences between the groups in mean QRS (cases 86.1, controls 86.2, mean difference 0.1, 95% confidence interval = -5.1 to 5.0 ms) or mean QT intervals (cases 354, controls 355, mean difference -0.8, 95% confidence interval = -10.7 to 9.2 ms).

CONCLUSIONS

Methylphenidate overdose is unlikely to have substantial effects on the QRS or QT intervals.

A case of suicide attempt with long-acting methylphenidate (Concerta)

The prescribed use of methylphenidate in the treatment of attention deficit hyperactivity disorder (ADHD) is widespread. The intranasal and parenteral abuse of methylphenidate (Ritalin) among teenagers is becoming increasingly more common, and deaths have been reported. Newer medical treatment options of long-acting stimulants offer effective treatment with a lower risk of abuse potential. We describe a case of a 17-year-old girl who had attempted suicide by ingesting 270 mg of Concerta. During the third years of treatment with Concerta, parents of patient reported that the patient had a depressive mood in the last week, and had attempted suicide with five tablets of Concerta 54 mg. She was sent to a local hospital with a diagnosis of long-acting methylphenidate overdose. All of vital and laboratory findings were normal except heart rate, which was 132 beats/min. Since more than 3 h have elapsed after the time of ingestion, activated charcoal administration was not carried out at the hospital. She was only observed for 12 h at the emergency department and later discharged from the hospital. While long-acting stimulants offer lower risk of abuse, their greater availability increases the likelihood of ingestion of this nature. Education of clinicians and families to be aware of this risk should reduce the frequency of this complication of treatment.

Evolution of stimulants to treat ADHD: transdermal methylphenidate

OBJECTIVE

The following comprehensive review describes the evolution of stimulant drug formulations used in the treatment of attention-deficit/hyperactivity disorder (ADHD). Emphasis is placed on the basic and clinical pharmacology of the dl-methylphenidate (MPH) transdermal system (MTS).

METHODS

The pharmacokinetic and pharmacodynamic literature pertaining to MPH and amphetamine enantiomers was reviewed in the context of ADHD therapy and MTS as a treatment option.

RESULTS

MTS incorporates MPH into an adhesive monolithic matrix, using the free base form of the drug to facilitate transdermal absorption. MTS technology minimizes contact dermatitis by eliminating to need for percutaneous penetration enhancers. After a lag time of approximately 2 h, plasma concentrations of the therapeutic d-MPH isomer become detectable, then continuously rise over the course of the recommended 9 h wear time. Concentrations of l-MPH typically attain 40-50% that of d-MPH (vs. 1-2% following oral MPH). Unauthorized MTS removal poses some misuse liability and over 50% of MTS drug content remains in the discarded system.

CONCLUSIONS

While liquid or chewable MPH formulations overcome potential swallowing difficulties, as do sprinkled once-daily extended-release (ER) MPH products, only MTS addresses swallowing difficulties while also offering a flexible individualized MPH exposure time in a once-daily MPH regimen.

Liquid chromatography-electrospray ionization mass spectrometry determination of methylphenidate and ritalinic acid in conventional and non-conventional biological matrices

A procedure based on liquid chromatography-electrospray ionization mass spectrometry is described for determination of methylphenidate (MPH) and its principal metabolite ritalinic acid (RA) in plasma, urine, oral fluid and sweat using 3,4-methylendioxypropylamphetamine (MDPA) as internal standard. Aliquots of 100microL biological fluids and sweat patch were initially treated with acetonitrile, centrifuged, and clear supernatants evaporated and redissolved in 10mM ammonium acetate. Chromatography was performed on a reversed-phase column using a gradient of 10mM ammonium acetate and acetonitrile as a mobile phase at a flow rate of 1mL/min. Separated analytes were confirmed and quantified by positive electrospray ionization mass spectrometry and selected ion monitoring acquisition mode. Limits of quantifications were 1ng/mL plasma, 1ng/sweat patch, 0.5ng/mL oral fluid and urine for MHF; 1ng/mL plasma and oral fluid, 1ng/sweat patch, 0.5ng/mL urine for RA using 100microL biological fluids or one sweat-patch per assay. Calibration curves were linear over the calibration ranges for both MPH and RA, with r(2)>0.99. At three concentrations spanning the linear dynamic range of the assay, mean recoveries ranged between 67.9-90.3% for MPH and 36.3-92.4% for RA in the different biological matrices. This method was applied to therapeutic monitoring of MHP and RA in conventional and non-conventional biological matrices from individuals in drug treatment.