Chapter 169: Prescription Drug Use and Misuse

INTRODUCTION

In 2015, prescription psychotherapeutic drugs such as pain relievers, tranquilizers, stimulants, and sedatives were used by 119 million Americans aged 12 and older—representing 44.5% of the population.¹ In the same year, approximately 18.9 million Americans (or 7.1% of the population) misused psychotherapeutic drugs; thus, a majority of people who used prescriptions drugs did not misuse them. Prescription pain relievers are the mostly commonly misused prescription drug (4.7%), followed by tranquilizers (2.3%), stimulants (2.0%), and sedatives (0.6%). For those who misuse prescription drugs, this misuse may result in substantial morbidity and mortality. In addition, prescription drug use and misuse may result in the disruption of social ties and engagement with the criminal justice system. Here we briefly review the pharmacology of different prescription drug classes, the epidemiology of prescription drug misuse as well as the medical consequences of misuse and evidence-based interventions for harm reduction and treatment.

PHARMACOLOGY OF PRESCRIPTION DRUGS USED FOR NONMEDICAL PURPOSES

A wide variety of prescription psychotherapeutic drugs are used for nonmedical purposes and several drug classes are represented. Pain relievers, tranquilizers, stimulants, and sedatives are the most commonly misused drugs.

Pain Relievers

Pain relievers include both opioid and nonopioid medications, but the focus of most surveillance systems are the opioid analgesic pain relievers including hydrocodone, oxycodone, tramadol, codeine, morphine, fentanyl, buprenorphine, oxymorphone, Demerol, hydromorpone, and methadone.² The opioid analgesics bind to the delta, kappa, and/or mu opioid receptors as agonists, partial agonists, and antagonists.³

Tranquilizers

Tranquilizers include benzodiazepines and muscle relaxants. Tranquilizers are distinguished from sedatives because they are typically prescribed as an anxiolytic or to relieve muscle spasms.² Benzodiazepines are sedative-hypnotics that modulate gamma-aminobutyric acid (GABA) receptors.⁴ Common benzodiazepines include chlordiazepoxide, diazepam, lorazepam, oxezepam, and clonazempa.^2,5 Some benzodiazepines function as muscle relaxants.⁵ Many of the other muscle relaxants, such as carisoprodol, are central nervous system (CNS) depressants.⁴ Carisoprodol also affects GABA receptors.⁴

Stimulants

Stimulants include amphetamine, methamphetamine, methylphenidate, anorectic stimulants (e.g., benzphetamine, diethylpropion, phendimetrazine, phentermine), and modafinil.² Amphetamine, methamphetamine, and methylphenidate are CNS stimulants that modulate catecholamine (i.e., noradrenaline and dopamine) reuptake and release.⁵

Sedatives

Sedatives include zolpidem, eszopiclone, zaleplon, benzodiazepine sedatives (e.g., flurazepam, temazepam, and triazolam), and barbiturates (e.g., phenobarbital, secobarbital).² Sedatives are distinguished from tranquilizers because they are typically prescribed for insomnia.² Zolpidem, eszopiclone, zaleplon, and barbiturates are nonbenzodiazepine sedative-hypnotics. Like benzodiazepines, these sedatives modulate GABA receptors.

EPIDEMIOLOGY OF NONMEDICAL PRESCRIPTION DRUG USE

Prevalence and Incidence

In 2015, prescription psychotherapeutic drugs were misused by 18.9 million Americans (or 7.1% of the population).¹ Globally, estimates are more difficult to summarize, due to different reporting conventions across countries. According ...