Pregabalin augmentation in treatment-resistant obsessive-compulsive disorder: a 16-week case series

[Pregabalin and risk of addiction: A new care issue?]

PURPOSE

Pregabalin (PRG) is a gamma-aminobutyric acid (GABA) analogue used for treatment of epilepsy, neuropathic pain, generalised anxiety disorder and currently being studied for other indications. Supported by the results of case studies and a limited number of studies, there is an ongoing debate about the addictive potential of PRG. However, evidence is scarce and no definitive assessment on the potential for abuse and dependence to PRG is available. The objective of our study was to identify the number of cases of abuse or dependence to PRG published and to study potential risk factors of addiction to PRG.

METHODS

We have identified on PubMed and ScienceDirect published case studies of PRG abuse or dependence and analysed these cases on the basis of several clinical parameters.

RESULTS

A total of 118 cases of PRG abuse or dependence were identified, including 21 isolated cases (mean age 33 years, 67 % men). The mean daily dose of PRG was 2,9 g. Current or past polydrug abuse was present in the majority of cases. Psychiatric diagnoses, other than substance-related disorders, were reported in as many patients, and almost all patients experienced withdrawal symptoms when PRG was discontinued.

CONCLUSION

Current literature suggests an important and growing concern for the abuse of PRG. Male sex, psychiatric and/or addiction history, including opioid addiction, may be potential risk factors for the development of addictive behaviours associated with PRG.

Bipolar disorder and gambling disorder comorbidity: current evidence and implications for pharmacological treatment

BACKGROUND

The co-occurrence of bipolar disorder (BD) and gambling disorder (GD), though of clinical and public health importance, is still scarcely investigated. Comorbid BD-GD subjects experience a more severe course of illness and poorer treatment outcome, due to a range of clinical and psychosocial factors that collectively impede remission and recovery. The aim of our paper is to review the role of pharmacotherapy in the treatment of comorbid BD-GD, in order to support clinical decisions according to the best available evidence.

METHODS

A qualitative systematic review of studies on pharmacological treatment in comorbid BD-GD was performed. A comprehensive literature search of online databases, bibliographies of published articles and gray literature was conducted. Data on efficacy, safety and tolerability were extracted and levels of evidence were assessed. We also provide a brief overview of current epidemiological, neurobiological and clinical findings, with the intention of proposing a dimensional approach to the choice of available drugs.

RESULTS

The only drug with a high level of evidence is lithium. Considering the inclusion of GD in DSM-5 'Substance-related and Addictive Disorders' category, we discuss the use of other drugs with a high level of evidence currently used in BD subjects with co-occurring substance use disorders.

LIMITATIONS

Only few clinical trials are available and the population is limited; therefore no conclusive evidence can be inferred.

CONCLUSIONS

Further randomized controlled trials are required to evaluate the efficacy of pharmacological treatment strategies in large samples of patients with comorbid BD-GD. Also, attempts should be made to identify other shared clinical and psychopathological domains that are amenable to treatment.

Clinical effectiveness of interventions for treatment-resistant anxiety in older people: a systematic review

BACKGROUND

Anxiety and related disorders include generalised anxiety disorder, obsessive-compulsive disorder, panic disorder, post-traumatic stress disorder and phobic disorders (intense fear of an object or situation). These disorders share the psychological and physical symptoms of anxiety, but each disorder has its own set of characteristic symptoms. Anxiety disorders can be difficult to recognise, particularly in older people (those aged over 65 years). Older people tend to be more reluctant to discuss mental health issues and there is the perception that older people are generally more worried than younger adults. It is estimated that between 3 and 14 out of every 100 older people have an anxiety disorder. Despite treatment, some people will continue to have symptoms of anxiety. People are generally considered to be 'resistant' or 'refractory' to treatment if they have an inadequate response or do not respond to their first treatment. Older adults with an anxiety disorder find it difficult to manage their day-to-day lives and are at an increased risk of comorbid depression, falls, physical and functional disability, and loneliness.

OBJECTIVE

To evaluate the effectiveness of pharmacological, psychological and alternative therapies in older adults with an anxiety disorder who have not responded, or have responded inadequately, to treatment.

DATA SOURCES

Electronic databases (MEDLINE, MEDLINE In-Process and Other Non-Indexed citations, EMBASE, The Cochrane Library databases, PsycINFO and Web of Science) were searched from inception to September 2013. Bibliographies of relevant systematic reviews were hand-searched to identify additional potentially relevant studies. ClinicalTrials.gov was searched for ongoing and planned studies.

REVIEW METHODS

A systematic review of the clinical effectiveness of treatments for treatment-resistant anxiety in older adults was carried out.

RESULTS

No randomised controlled trial or prospective comparative observational study was identified meeting the prespecified inclusion criteria. Therefore, it was not possible to draw any conclusions on clinical effectiveness.

LIMITATIONS

As no study was identified in older adults, there is uncertainty as to which treatments are clinically effective for older adults with an anxiety disorder who have not responded to prior treatment. The comprehensive methods implemented to carry out this review are a key strength of the research presented. However, this review highlights the extreme lack of research in this area, identifying no comparative studies, which is a marked limitation.

CONCLUSIONS

Specific studies evaluating interventions in older adults with an anxiety disorder who have not responded to first-line treatment are needed to address the lack of evidence. The lack of evidence in this area means that older adults are perhaps receiving inappropriate treatment or are not receiving a particular treatment because there is limited evidence to support its use. At this time there is scope to develop guidance on service provision and, as a consequence, to advance the standard of care received by older adults with a treatment-resistant anxiety disorder in primary and secondary care. Evaluation of the relative clinical effectiveness and acceptability of pharmacological and psychological treatment in older adults with an anxiety disorder that has not responded to first-line treatment is key future research to inform decision-making of clinicians and patients. An important consideration would be the enrolment of older adults who would be representative of older adults in general, i.e. those with multiple comorbid physical and mental disorders who might require polypharmacy.

STUDY REGISTRATION

The protocol for the systematic review is registered on PROSPERO (registration number CRD42013005612).

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Effectiveness of pregabalin as monotherapy or combination therapy for neuropathic pain in patients unresponsive to previous treatments in a Spanish primary care setting

Background and Objective

Patients from a previous study of neuropathic pain (NP) in the Spanish primary care setting still had symptoms despite treatment. Subsequently, patients were treated as prescribed by their physician and followed up for 3 months. Since pregabalin has been shown to be effective in NP, including refractory cases, the objective of this study was to assess the effectiveness of pregabalin therapy in patients with NP refractory to previous treatments.

Methods

This was a post hoc analysis of pregabalin-naïve NP patients treated with pregabalin in a 3-month follow-up observational multicenter study to assess symptoms and satisfaction with treatment. Patients were evaluated with the Douleur Neuropathique en 4 questions (DN4), the Brief Pain Inventory (BPI) and the Treatment Satisfaction for Medication Questionnaire (SATMED-Q) overall satisfaction domain.

Results

1,670 patients (mean age 58 years, 59 % women), previously untreated or treated with ≥1 drug other than pregabalin, were treated with pregabalin (37 % on monotherapy). At 3 months, pain intensity and its interference with activities decreased by half (p < 0.0001), while the number of days with no or mild pain increased by a mean of 4.5 days (p < 0.0001). Treatment satisfaction increased twofold (p < 0.0001). Patients with a shorter history of pain and those with neuralgia and peripheral nerve compression syndrome (PCS) as etiologies had the highest proportion on monotherapy and showed the greatest improvements in pain-related parameters in their respective group categories.

Conclusion

Treatment with pregabalin (as monotherapy or combination therapy) provides benefits in pain and treatment satisfaction in patients with NP, including refractory cases. Shorter disease progression and neuralgia and PCS etiologies are favorable factors for pregabalin treatment response.

Pregabalin in clinical psychiatry and addiction: pros and cons

Pregabalin acts as a presynaptic modulator of excitatory neurotransmitter release, binding to the α²-δ subunit protein of voltage-gated calcium channels. Pregabalin use is becoming widespread in the psychiatric scenario. Data are encouraging, with some good evidence for efficacy in anxious spectrum, benzodiazepine abuse/dependence, and alcoholism. The abuse potential, however, is an issue that should be taken into account, mostly in subjects at risk for developing substance/alcohol misuse.

The effect of pregabalin on sensorimotor gating in 'low' gating humans and mice

Pregabalin, an anticonvulsant and anxiolytic compound that binds to α2-δ auxiliary subunit Types 1 and 2 of voltage-gated calcium channels, has been shown to reduce excitatory neurotransmission partially through modulation of glutamatergic signaling. Prepulse inhibition (PPI) of startle is an operational measure of sensorimotor gating impacted by disruption of the glutamatergic system and is reduced in schizophrenia patients. Dysregulation of the glutamatergic system has also been implicated in the pathophysiology of schizophrenia. Here we tested the hypothesis that pregabalin may ameliorate PPI in a model of deficient gating in humans and mice. In study 1, 14 healthy human subjects participated in a within subjects, cross-over study with placebo, 50 mg or 200 mg pregabalin treatment prior to undergoing a PPI task. In study 2, 24 C57BL/6 mice underwent a similar procedure with vehicle, 30 and 100 mg/kg dose treatments. In both studies, subjects were assigned to a "Low" or "High" gating group using a median split procedure based on their PPI performance during placebo/vehicle. Drug effects were then examined across these groups. In humans, pregabalin treatment significantly increased PPI performance in the "low gating" group. In mice, pregabalin treatment significantly increased PPI in the low gating group but reduced PPI in the high gating group. Across species, pregabalin treatment improves PPI in subjects with low gating. These data support further exploration of pregabalin as a potential treatment for disorders characterized by sensorimotor gating deficits and glutamatergic hypersignaling, such as schizophrenia.