LDX

LDX
IUPAC name	(6aR,9R)-N,N-diethyl-7-methyl-4,6,6a,7,8,9-hexahydroindolo[4,3-fg]quinoline-9-carboxamide
OtherNames	Lisdexamfetamine dimesylate

LDX. It is a central nervous system stimulant prodrug primarily prescribed for the treatment of attention deficit hyperactivity disorder (ADHD) and binge eating disorder. Following oral administration, it is converted in the body to the active moiety dextroamphetamine, which is responsible for its therapeutic effects. The prodrug design aims to provide a longer duration of action and a reduced potential for abuse compared to immediate-release amphetamine formulations.

Overview

LDX was developed by the pharmaceutical company New River Pharmaceuticals and received initial approval from the U.S. Food and Drug Administration (FDA) for ADHD in 2007. It is marketed under the brand name Vyvanse by Shire plc, which was later acquired by Takeda Pharmaceutical Company. The medication is classified as a Schedule II controlled substance under the Controlled Substances Act in the United States, indicating a high potential for abuse but also an accepted medical use. Its development represented a significant advancement in the long-term management of ADHD symptoms.

Chemical Properties and Synthesis

Chemically, LDX consists of the amino acid L-lysine covalently bound to dextroamphetamine. This bond is designed to be cleaved by enzymatic activity in the red blood cells, specifically by hydrolytic enzymes. The synthesis involves coupling the carboxyl group of L-lysine to the amine group of dextroamphetamine, forming an amide linkage. This prodrug is inherently inactive; its pharmacological activity is entirely dependent on this conversion process, which occurs primarily after absorption from the gastrointestinal tract.

Medical Applications

The primary FDA-approved indications for LDX are the treatment of ADHD in patients aged six and older and the treatment of moderate to severe binge eating disorder in adults. In clinical trials, such as those reviewed by the FDA, it demonstrated significant efficacy in reducing symptoms of inattention and hyperactivity as measured by tools like the ADHD Rating Scale. For binge eating disorder, it reduces the number of binge eating days per week. It is not approved for weight loss or obesity treatment. Treatment is typically part of a comprehensive therapeutic program that may include psychological counseling and behavioral therapy.

Pharmacodynamics and Pharmacokinetics

LDX itself does not bind to the targets associated with amphetamine pharmacology. After conversion to dextroamphetamine, the drug increases the levels of the neurotransmitters dopamine and norepinephrine in the synaptic cleft by interacting with the vesicular monoamine transporter 2 (VMAT2) and inhibiting the dopamine transporter (DAT) and norepinephrine transporter (NET). Pharmacokinetically, following oral administration, the conversion to dextroamphetamine is gradual, resulting in a smooth plasma concentration-time profile with a time to peak concentration of approximately 3.5 hours. The elimination half-life of dextroamphetamine derived from LDX is about 12 hours.

Safety and Side Effects

Common adverse reactions include decreased appetite, insomnia, dry mouth, irritability, and increased heart rate. Serious side effects can include psychosis, mania, cardiovascular events such as hypertension and tachycardia, and peripheral vasculopathy. There is a boxed warning regarding its high potential for abuse and dependence. Contraindications include advanced arteriosclerosis, symptomatic cardiovascular disease, moderate to severe hypertension, hyperthyroidism, known hypersensitivity, and concomitant use with monoamine oxidase inhibitors (MAOIs). Its safety profile has been evaluated in post-marketing studies monitored by the FDA.

Society and Culture

The introduction of LDX had a notable impact on the pharmaceutical market for ADHD treatments. High-profile events, such as the acquisition of New River Pharmaceuticals by Shire plc for over $2 billion, underscored its commercial significance. It has been the subject of media discussion regarding stimulant use, cognitive enhancement, and drug diversion. The medication has also been involved in legal settlements, such as Shire's agreement with the U.S. Department of Justice regarding marketing practices. Furthermore, its patent expiration and the subsequent entry of generic versions have been significant events in the healthcare industry.

Category:Stimulants Category:Prodrugs Category:Central nervous system agents