What is Pregabalin and why is it prescribed?
Pregabalin (Lyrica) is one of a group of drugs called gabapentinoids. The structure of gabapentinoids resembles the neurotransmitter gammaamino butyric acid (Gaba), which has its own brain receptors.
Gaba is central to the anxietyrelieving action of drugs such as benzodiazepines. However, gabapentinoids do not act directly on brain Gaba receptors and have different biological effects.
The exact way that pregabalin works is not fully understood, but it is thought to affect the way that calcium enters nerve cells. This reduces the activity of some of the nerve cells in the brain and spinal cord, reducing the release of other neurotransmitters that are involved in pain, epilepsy and anxiety.
Originally approved for use in 2004, Lyrica has a product licence for three indications in Ireland: pain associated with certain types of nerve damage; epilepsy; and for the treatment of generalised anxiety disorder.
According to the drug’s official summary of product characteristics (SPC), “after discontinuation of short-term and long-term treatment with pregabalin, withdrawal symptoms have been observed in some patients.
The following events have been mentioned: insomnia, headache, nausea, anxiety, diarrhoea, flu syndrome, nervousness, depression, pain, convulsion, hyperhidrosis (excessive sweating) and dizziness, suggestive of physical dependence . . . Convulsions... may occur during pregabalin use or shortly after discontinuing pregabalin.
“Concerning discontinuation of long-term treatment of pregabalin, data suggest that the incidence and severity of withdrawal symptoms may be dose-related.”
The SPC also warns of potential abuse or dependence with pregabalin: “Cases of misuse, abuse and dependence have been reported. Caution should be exercised in patients with a history of substance abuse and the patient should be monitored for symptoms of pregabalin misuse, abuse or dependence (development of tolerance, dose escalation, drug-seeking behaviour have been reported).”