Pregabalin dependence

Sir,

Pregabalin is a GABA mimetic drug, commonly prescribed for neuropathic pain, fibromyalgia, and partial onset seizures. In recent times, there has been reports highlighting its abuse potential.[1,2,3] Here, the authors report a case of pregabalin dependence with comorbid depression and opioid dependence with intricacy of presentation and management.

A 34-year-old male presented to psychiatry outpatient department in 2013 with depressive symptoms, which improved with antidepressant. In 2014, he developed lumbar disc prolapse for which he was advised analgesic and pregabalin up to 150 mg/day. Although the backache started improving, he himself increased the dose of pregabalin up to 350 mg/day. He felt relaxed, calm, and euphoric. Thereafter, he continued using pregabalin without consultation. He would now experience anxiety, insomnia, sadness of mood, loss of interest in earlier pleasurable activities and decreased appetite on skipping pregabalin. These symptoms would improve immediately on taking pregabalin. Similar pattern continued for the next 3 years. In 2017, he experienced another depressive episode. Antidepressants were changed sequentially but he did not improve. He became noncompliant to antidepressants and was lost to follow-up. Subsequently, he started consuming heroin (through chasing method) to relieve his distress that gradually progressed to dependence pattern. During this entire period, he continued pregabalin in a similar dose (350 mg/day). He was admitted to in 2019 for pregabalin and opioid dependence. Initially, he had a Clinical Opioid Withdrawal scale (COWS) score of 9, Hamilton Anxiety Rating Scale (HAM-A) score of 4, and Hamilton Depression Rating (HAM-D) Scale score of 7. Pregabalin was tapered down to 75 mg/day within 24 h, along with detoxification for opioid using non-opioid analgesics and clonidine. On 5^th day of admission, pregabalin was stopped completely, following which patient had rapid emergence of symptoms of anxiety, insomnia, sadness of mood, loss of interest, and decreased appetite. Scores on HAM-A increased from 4 to 13 and HAM-D increased from 7 to 16 within 12 h with no changes in COWS score. He was prescribed T. Clonazepam 1.5 mg/day in divided doses, T. Zolpidem 10 mg and T. Propranolol 40 mg/day for managing these symptoms. In next 4 days, the patient symptoms improved markedly and HAM-A score again decreased to 4 and HAM-D to 7. He was then discharged on naltrexone maintenance therapy in satisfactory condition.

The case highlights the risk of pregabalin dependence even when used in therapeutic range for a particular indication. The dose-related GABA mimetic action causing euphoria is the contributing factor in its abuse potential and individual variability in GABA-mimetic euphoric action can be the reason that abuse is not seen in majority of the patients. Individual factors like history of substance use may facilitate this action leading to increased risk of abuse. Although past reports have shown that pregabalin dependence is more common in patient with prior substance use disorder,[4] findings of the index case are in contrary to this finding as the substance use, i.e., opioid use was started after the pregabalin dependence was already established.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.