Some years ago I was prescribed the painkiller pregabalin. I had neuropathic pain from a slipped disc, and the drug, marketed as Lyrica, is approved for use for this type of pain. It worked well, although it was accompanied by a certain “muzziness” in my head, which, truth be known, didn’t bother me as long as the tablet was successfully hitting the pain.
A few weeks later, however, was a different story. I was gradually reducing the dose, as recommended, when some strange symptoms emerged. I developed aches and pains all over, as you would with a dose of flu. The muzziness became a strange kind of floating feeling accompanied by intermittent dizzy spells. And I felt incredibly tense, as if pressure was building up inside my head.
The symptoms resolved somewhat when I went back on the previous dose. But it was the beginning of a four-month struggle to come off the drug. Only by titrating the dose down extremely slowly was I able to make progress.
Even so, the final reduction to zero was tough; for about a week my body was craving the drug as many of the original withdrawal symptoms returned.
Pregabalin is one of a group of drugs called gabapentinoids. The structure of gabapentinoids resembles the neurotransmitter gamma-amino butyric acid (Gaba), which has its own brain receptors. Gaba is central to the anxiety-relieving 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).”
There has been a fivefold increase in the number of reports of "abuse", "misuse" and "dependence" for gabapentinoids as part of adverse drug reaction reporting in the UK since 2010. In the Republic, researchers from the National Drug Treatment Centre, writing in the Irish Medical Journal last January, flagged their concerns about pregabalin.
“Our study (which showed a misuse rate of 7 per cent) confirms that pregabalin abuse is taking place among the addiction services population. We believe that misuse of this prescription drug is a serious emerging issue which should be monitored carefully.”
Unfortunately, we have been here before. In the early 1960s, the benzodiazepines Librium and Valium became the first drugs to enter the mass market to treat anxiety. It took decades of overprescribing “mother’s little helper” before doctors finally acknowledged that the drug was highly addictive.
Have you been prescribed Lyrica? I would like to hear about your experience with the drug. Email your stories, in confidence, to mhouston@irishtimes.com
mhouston@irishtimes.com @muirishouston