Pregabalin

Pregabalin (INN) (IPA: ) is an anticonvulsant drug used for neuropathic pain, as an adjunct therapy for partial seizures, and in generalized anxiety disorder. It was designed as a more potent successor to gabapentin. Pregabalin is marketed by Pfizer under the trade name Lyrica.

Recent studies have shown that pregabalin is effective at treating chronic pain in disorders such as fibromyalgia and spinal cord injury

It is considered to have a dependence liability if misused, and is classified as a Schedule V drug in the U.S.

History
Pregabalin was initially developed by biochemist Richard Silverman at Northwestern University in the United States. The drug was approved in the European Union in 2004. Pregabalin received U.S. Food and Drug Administration (FDA) approval for use in treating epilepsy, diabetic neuropathy pain and post-herpetic neuralgia pain in June 2005, and appeared on the U.S. market in fall 2005.

Pharmacology
Like gabapentin, pregabalin binds to the α2δ subunit of the voltage-dependent calcium channel in the central nervous system. However, the exact mechanism of action is unknown.

Indications
Pregabalin is indicated for:
 * Treatment of neuropathic pain in adults
 * Adjunctive therapy in adults with partial seizures with or without secondary generalization
 * Fibromyalgia pain. The FDA has approved Pregabalin as an indicated use on June 21, 2007.

In the European Union, it has also been approved for the treatment of generalized anxiety disorder (GAD).

Adverse effects
Adverse drug reactions associated with the use of pregabalin include:
 * Very common (>10% of patients): dizziness, drowsiness
 * Common (1–10% of patients): visual disturbance (including blurred vision, diplopia), ataxia, dysarthria, tremor, lethargy, memory impairment, euphoria, weight gain, constipation, dry mouth, peripheral edema, loss or decrease of libido, erectile dysfunction
 * Infrequent (0.1–1% of patients): depression, confusion, agitation, hallucinations, myoclonus, hypoaesthesia, hyperaesthesia, tachycardia, excessive salivation, sweating, flushing, rash, muscle cramp, myalgia, arthralgia, urinary incontinence, dysuria, thrombocytopenia, Kidney calculus
 * Rare (<0.1% of patients): neutropenia, first degree heart block, hypotension, hypertension, pancreatitis, dysphagia, oliguria, rhabdomyolysis

Drug interactions
No pharmacokinetic interactions have been demonstrated in vivo. The manufacturer notes some potential pharmacological interactions with oxycodone, lorazepam and ethanol (alcohol). Concurrent use may increase the central nervous system effects of these medications (e.g. drowsiness, effects on concentration).