Investigators analyzed prescription drug claims for over 9.1 million U.S. adults over a 1-year period and found that 276,223 (3%) had used a schedule II stimulant, such as methylphenidate and amphetamines, during that time. Of these 276,223 patients, 45% combined these agents with one or more additional CNS-active drugs and almost 25% were simultaneously using two or more additional CNS-active drugs.
Close to half of the stimulant users were taking an antidepressant, while close to one-third filled prescriptions for anxiolytic/sedative/hypnotic meditations, and one-fifth received opioid prescriptions.
The widespread, often off-label use of these stimulants in combination therapy with antidepressants, anxiolytics, opioids, and other psychoactive drugs, “reveals new patterns of utilization beyond the approved use of stimulants as monotherapy for ADHD, but because there are so few studies of these kinds of combination therapy, both the advantages and additional risks [of this type of prescribing] remain unknown,” study investigator Thomas J. Moore, AB, faculty associate in epidemiology, Johns Hopkins Bloomberg School of Public Health and Johns Hopkins Medicine, Baltimore, told this news organization.
The study was published online in BMJ Open.
Amphetamines and methylphenidate are CNS stimulants that have been in use for almost a century. Like opioids and barbiturates, they’re considered “dangerous” and classified as schedule II Controlled Substances because of their high potential for abuse.
Over many years, these stimulants have been used for multiple purposes, including nasal congestion, narcolepsy, appetite suppression, binge eating, depression, senile behavior, lethargy, and ADHD, the researchers note.
Observational studies suggest medical use of these agents has been increasing in the United States. The investigators conducted previous research that revealed a 79% increase from 2013 to 2018 in the number of adults who self-report their use. The current study, said Mr. Moore, explores how these stimulants are being used.
For the study, data was extracted from the MarketScan 2019 and 2020 Commercial Claims and Encounters Databases, focusing on 9.1 million adults aged 19-64 years who were continuously enrolled in an included commercial benefit plan from Oct. 1, 2019 to Dec. 31, 2020.
The primary outcome consisted of an outpatient prescription claim, service date, and days’ supply for the CNS-active drugs.
The researchers defined “combination-2” therapy as 60 or more days of combination treatment with a schedule II stimulant and at least one additional CNS-active drug. “Combination-3” therapy was defined as the addition of at least two additional CNS-active drugs.
The researchers used service date and days’ supply to examine the number of stimulant and other CNS-active drugs for each of the days of 2020.
CNS-active drug classes included antidepressants, anxiolytics/sedatives/hypnotics, antipsychotics, opioids, anticonvulsants, and other CNS-active drugs.
Of the total number of adults enrolled, 3% (n = 276,223) were taking schedule II stimulants during 2020, with a median of 8 (interquartile range, 4-11) prescriptions. These drugs provided 227 (IQR, 110-322) treatment days of exposure.
Among those taking stimulants 45.5% combined the use of at least one additional CNS-active drug for a median of 213 (IQR, 126-301) treatment days; and 24.3% used at least two additional CNS-active drugs for a median of 182 (IQR, 108-276) days.
“Clinicians should beware of the prescribing cascade. Sometimes it begins with an antidepressant that causes too much sedation, so a stimulant gets added, which leads to insomnia, so alprazolam gets added to the mix,” Mr. Moore said.
He cautioned that this “leaves a patient with multiple drugs, all with discontinuation effects of different kinds and clashing effects.”
These new findings, the investigators note, “add new public health concerns to those raised by our previous study. ... this more-detailed profile reveals several new patterns.”
Most patients become “long-term users” once treatment has started, with 75% continuing for a 1-year period.
“This underscores the possible risks of nonmedical use and dependence that have warranted the classification of these drugs as having high potential for psychological or physical dependence and their prominent appearance in toxicology drug rankings of fatal overdose cases,” they write.
They note that the data “do not indicate which intervention may have come first – a stimulant added to compensate for excess sedation from the benzodiazepine, or the alprazolam added to calm excessive CNS stimulation and/or insomnia from the stimulants or other drugs.”
Several limitations cited by the authors include the fact that, although the population encompassed 9.1 million people, it “may not represent all commercially insured adults,” and it doesn’t include people who aren’t covered by commercial insurance.
Moreover, the MarketScan dataset included up to four diagnosis codes for each outpatient and emergency department encounter; therefore, it was not possible to directly link the diagnoses to specific prescription drug claims, and thus the diagnoses were not evaluated.
“Since many providers will not accept a drug claim for a schedule II stimulant without an on-label diagnosis of ADHD,” the authors suspect that “large numbers of this diagnosis were present.”