Attention deficit hyperactivity disorder management
There are two major medications derived from methylphenidate's isomers: a racemic mixture of half d-threo-methylphenidate and half l-threo-methylphenidate called methylphenidate (Ritalin, Concerta), and an enantiopure formulation containing just d-threo-methylphenidate called dexmethylphenidate (Focalin).
Pregabalin
Pregabalin, marketed under the brand name Lyrica among others, is a medication used to treat epilepsy, neuropathic pain, fibromyalgia, and generalized anxiety disorder. It is a gabapentinoid and acts by inhibiting certain calcium channels. Its use for epilepsy is as an add-on therapy for partial seizures with or without secondary generalization in adults. Some off-label uses of pregabalin include restless leg syndrome, prevention of migraines, anxiety disorders, and alcohol withdrawal. When used before surgery, there have been varying accounts of its perioperative analgesia effects, specifically as it relates to chronic pain. However, some suggest that pregabalin improves postoperative analgesia compared with placebo, at the expense of increased sedation and visual disturbances.
Common side effects include: sleepiness, confusion, trouble with memory, poor motor coordination, dry mouth, problem with vision, and weight gain. Potentially serious side effects include angioedema, drug misuse, and an increased suicide risk. When pregabalin is taken at high doses over a long period of time, addiction may occur, but if taken at usual doses the risk of addiction is low. 
Parke-Davis developed pregabalin as a successor to gabapentin and was brought to market by Pfizer after the company acquired Warner-Lambert. There was no generic version available in the United States until 2018. A generic version is available in Canada, the United Kingdom, Australia and Germany. In the US it costs about $300–$400 per month. Pregabalin is a Schedule V controlled substance under the Controlled Substances Act of 1970.
Pregabalin is useful when added to other treatments, when those other treatments are not controlling partial epilepsy. Its use alone is less effective than some other seizure medications. It is unclear how it compares to gabapentin for this use.