INTRODUCTION

Methylphenidate is a psychostimulant that inhibits the reuptake of dopamine (DA) and norepinephrine (NE), increasing the amount of these monoamines in the synaptic cleft. Methylphenidate inhibits the reuptake of these monoamines by blocking their transporters: dopamine transporter (DAT) and noradrenaline transporter (NET), presenting greater affinity for DAT than for NET¹.

Methylphenidate has structural and pharmacological similarity with drugs such as cocaine and D-amphetamine, so there is reason to suspect that it may have a potential for significant abuse².

Currently in Spain, methylphenidate is only approved for attention deficit hyperactivity disorder (ADHD) in children from 6 years of age when other measures by themselves have proven to be insufficient³.

Treatment with methylphenidate is not indicated for all children with this syndrome and the decision to use the drug should be based on a very complete assessment of the severity and chronicity of the child's symptoms in relation to their age³.

There are different commercial presentations currently available on the market. The technical data sheet of some presentations (Equasym®, Medikinet® and Rubifen®) specifies that they are not indicated for adults. The rest of the presentations do not rule out this possibility for teenagers patients whose symptoms persist until adulthood and who have demonstrated a clear benefit. However, it is not appropriate to start treatment in adulthood³.

Regarding long-term use of methylphenidate (more than 12 months), the safety and efficacy of methylphenidate treatment have not been systematically evaluated in controlled studies. Treatment with methylphenidate should not be and is not required to be indefinite, it is usually suspended during or after puberty³.

In the last decades, the diagnosis of ADHD and the use of stimulants has increased significantly, reaching up to triple the prescription rate of methylphenidate⁴.

Other clinical uses, outside the technical specifications described in the bibliography, are:

The use of medical stimulants such as methylphenidate to enhance intellectual capacity is increasing in some countries not only in patients with brain disorders but also in healthy individuals. Patients who consume cognition-enhancing drugs are at risk of developing dependence and suffer adverse effects due to the abuse of these substances¹³,¹⁴,¹⁵.

The aim of our study was to analyse the suitability of the prescription of methylphenidate in adult patients in the South of Seville Healthcare Management Area (SSHMA).

METHODS

Retrospective observational prescription-indication study of the use of methylphenidate in the South of Seville Healthcare Management Area. All adult patients (>18 years old) who had active methylphenidate prescriptions in September 2018 were included.

The following variables were collected: demographic (age and sex) and clinical (indication of treatment, total daily dose, posology, duration of treatment).

As outcome variables were collected: percentage of patients with off-label indications, percentage of patients with inadequate doses and percentage of patients with treatment duration of more than one year.

Patients with active prescription of methylphenidate from the SSHMA were obtained from the application LISTADOS®. The rest of the variables were collected from the digital clinical history (Diraya®) and from the prescription module (Prescripciones 5®).

RESULTS

Indication study

The prescription indications for methylphenidate were collected in table 1. 36.26% of the patients presented indications not included in the technical data sheet.

Table 1.  Indications of methylphenidate prescription 

ADHD: attention deficit hyperactivity disorder; OSAHS: obstruvtive sleep apnea-hypopnea syndrome.

DISCUSSION

The diagnosis that most frequently motivated the prescription of methylphenidate was ADHD, which is the indication for which it is intended. This states that CNS stimulants continue to be the first pharmacological line for this pathology. However, methylphenidate has not been approved in adults or the elderly, as there are no safety studies in these populations.

The increase in prescriptions and the prolongation of their duration is likely to cause an increase in adverse effects, despite the fact that most individuals with ADHD adequately use their medications¹⁷.

In the study population, the largest number of patients who consumed methylphenidate were included in the age group (18-25 years) who maintained the treatment initiated during childhood, which has not been suspended.

It was found that not all the prescribed doses were within the ranges recommended by the data sheet. Doses higher than these are associated with signs of generalized central CNS stimulation that can culminate in convulsions². In our case, 7 patients had prescribed doses higher than those recommended.

CONCLUSIONS

This study demonstrates the different patterns in the prescription of methylphenidate in adults. Draws attention, the long duration of treatment with methylphenidate and the non-suspension of it during adulthood. In addition, it is observed that the use of methylphenidate outside indications of technical data sheet is a common practice in adults. These prescription patterns imply the need to incorporate strategies to minimize the risk of adverse reactions and the risk of misuse or abuse, particularly in the elderly.

Funding source: The present investigation has not received specific aid from agencies from the public sector, commercial sector or non-profit entities.