Muscimol prevents long-lasting potentiation of dorsal horn field potentials in rats with chronic constriction injury exhibiting decreased levels of the GABA transporter GAT-1

The inhibitory activity of gamma-aminobutyric acid (GABA) is considered critical in setting the conditions for synaptic plasticity, and many studies support an important role of GABA in the suppression of nociceptive transmission in the dorsal horn. Consequently, any injury-induced modification of the GABA action has the potential to critically modify spinal synaptic plasticity. We have previously reported that chronic constriction injury of the sciatic nerve was accompanied by long-lasting potentiation of superficial spinal dorsal horn field potentials following high-frequency tetanus. In this study we examined whether the GABA-A receptor agonist muscimol would modify post-tetanic responses in rats with chronic constriction injury. In animals exhibiting maximal thermal hyperalgesia as one sign of neuropathic pain 7 days after loose ligation of the sciatic nerve, spinal application of muscimol (5, 10 or 20 microg) before the high-frequency (50 Hz) tetanus produced a long-lasting depression (rather than potentiation) of spinal dorsal horn field potentials. In separate but related Western immunoblot experiments, we also established that the chronic constriction injury was accompanied by significant decreases in the content of the GABA transporter GAT-1. These data demonstrated that GABA-A receptor agonists may effectively influence the expression of long-lasting synaptic plasticity in the spinal dorsal horn, and that an injury-induced loss in GABA transporter content may have contributed to a depletion of GABA from its terminals within the spinal dorsal horn. These data lent further support to the notion that the loss of GABA inhibition may have important consequences for the development of neuropathic pain.

Pricing and Reimbursement of Biosimilars in Central and Eastern European Countries

Objectives: The aim of this study was to review the requirements for the reimbursement of biosimilars and to compare the reimbursement status, market share, and reimbursement costs of biosimilars in selected Central and Eastern European (CEE) countries. Methods: A questionnaire-based survey was conducted between November 2016 and January 2017 among experts from the following CEE countries: Bulgaria, Czech Republic, Croatia, Estonia, Hungary, Latvia, Lithuania, Poland, Slovakia, and Romania. The requirements for the pricing and reimbursement of biosimilars were reviewed for each country. Data on the extent of reimbursement of biologic drugs (separately for original products and biosimilars) in the years 2014 and 2015 were also collected for each country, along with data on the total pharmaceutical and total public health care budgets. Results: Our survey revealed that no specific criteria were applied for the pricing and reimbursement of biosimilars in the selected CEE countries; the price of biosimilars was usually reduced compared with original drugs and specific price discounts were common. Substitution and interchangeability were generally allowed, although in most countries they were at the discretion of the physician after a clinical assessment. Original biologic drugs and the corresponding biosimilars were usually in the same homogeneous group, and internal reference pricing was usually employed. The reimbursement rate of biosimilars in the majority of the countries was the same and amounted to 100%. Generally, the higher shares of expenditures were shown for the reimbursement of original drugs than for biosimilars, except for filgrastim, somatropin, and epoetin (alfa and zeta). The shares of expenditures on the reimbursement of biosimilar products ranged from 8.0% in Estonia in 2014 to 32.4% in Lithuania in 2015, and generally increased in 2015. The share of expenditures on reimbursement of biosimilars in the total pharmaceutical budget differed between the countries, with the highest observed value for Slovakia and Hungary and the lowest-for Croatia. Conclusions: The requirements for the pricing and reimbursement of biosimilar products as well as the access of patients to biologic treatment do not differ significantly between the considered CEE countries. Biosimilar drugs significantly influence the reimbursement systems of these countries, and the expenditure on the reimbursement of biosimilars is increasing as they are becoming more accessible to patients.

Pharmaceutical Regulation in Central and Eastern European Countries: A Current Review

Objectives: The aim of this study was to review reimbursement environment as well as pricing and reimbursement requirements for drugs in selected Central and Eastern Europe (CEE) countries. Methods: A questionnaire-based survey was performed in the period from November 2016 to March 2017 among experts involved in reimbursement matters from CEE countries: Bulgaria, Croatia, Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Slovakia, and Romania. A review of requirements for reimbursement and implications of Health Technology Assessment (HTA) was performed to compare the issues in above-mentioned countries. For each specified country, data for reimbursement costs, total pharmaceutical budget, and total public health care budget in the years 2014 and 2015 were also collected. Questionnaires were distributed via emails and feedback data were obtained in the same way. Additional questions, if any, were also submitted to respondents by email. Pricing and reimbursement data were valid for March 2017. Results: The survey revealed that the relation of drug reimbursement costs to total public healthcare spending ranged from 0.12 to 0.21 in the year 2014 and 2015 (median value). It also revealed that pricing criteria for drugs, employed in the CEE countries, were quite similar. External reference pricing as well as internal reference pricing were common in mentioned countries. Positive reimbursement lists were valid in all countries of the CEE region, negative ones were rarely used; reimbursement decisions were regularly revised and updated in the majority of countries. Copayment was common and available levels of reimbursement differed within and between the countries and ranged from 20 to 100%. Risk-sharing schemes were often in use, especially in the case of innovative, expensive drugs. Generic substitution was also possible in all analyzed CEE countries, while some made it mandatory. HTA was carried out in almost all of the considered CEE countries and HTA dossier was obligatory for submitting a pricing and reimbursement application. Conclusions: Pricing and reimbursement requirements are quite similar in the CEE region although some differences were identified. HTA evaluations are commonly used in considered countries.

Changes in post-tetanic potentiation of A-fiber dorsal horn field potentials parallel the development and disappearance of neuropathic pain after sciatic nerve ligation in rats

Significant plastic changes in spinal nociceptive processing appear to accompany peripheral nerve injury or inflammation. Using a well-established model of neuropathic pain, we have recently reported that loose ligation of the sciatic nerve was accompanied by a long-lasting post-tetanic potentiation of sciatic-evoked A-fiber superficial dorsal horn field potentials. In the present study we demonstrate that the typical disappearance of thermal hyperalgesia as a behavioral sign of neuropathic pain several weeks after loose sciatic nerve ligation is accompanied by the loss of the long-lasting potentiation. These data suggest that a significant but reversible shift in the processing of sensory information in the spinal dorsal horn follows peripheral nerve injury, and lend further support to the notion that long-lasting synaptic plasticity may contribute to the development of neuropathic pain.

Comparative Analysis of Legislative Requirements About Patients' Access to Biotechnological Drugs for Rare Diseases in Central and Eastern European Countries

Objectives: The aim of the study was to compare the access of patients with rare diseases (RDs) to biotechnological drugs in several Central and Eastern European countries (CEECs). We focused on the legislative pricing and reimbursement requirements, availability of biotechnological orphan medicinal products (BOMPs) for RDs, and reimbursement expenditures. Methods: A questionnaire-based survey was conducted among experts from 10 CEECs: Bulgaria, Croatia, Estonia, Greece, Hungary, Poland, Romania, Slovakia, Serbia, and Macedonia. The legal requirements for reimbursement and pricing of BOMPs were collected. All BOMPs and medicines without prior orphan designations were extracted from the European list of orphan medicinal products, 2017. The reimbursement status of these medicinal products in 2017 in the public coverage of the included CEECs as well as the share of their costs in relation to the total public pharmaceutical spending for the period from 2014 to 2016 were defined. Results: Our survey revealed that some differences in the legal requirements for pricing and reimbursement of BOMPs amongst the countries included in the study. All European Union countries have developed and implemented pharmacoeconomic guidelines with or without some specific reimbursement requirements for orphan medicinal products. Cost-effectiveness analysis, cost-utility analysis, Markov models, meta-analysis, and discount levels of costs and results were required only in Bulgaria, Poland and Hungary. The number of reimbursed BOMPs and biotechnological medicinal products for RDs without prior orphan designation was the highest in Hungary (17 and 40, respectively). Patient-based reimbursement schemes were available only in Hungary for 11 out of 17 BOMPs. Poland and Greece have the highest pharmaceutical expenditure of reimbursed BOMPs with are ~214 million and 180 million EUR, respectively in the observed period from 2014 to 2016. High proportion of the pharmaceutical expenditure on the reimbursed biotechnological medicinal products for RDs for the observed period 2014-2016 is presented in Bulgaria and Slovakia. Conclusions: The non-European Union CEECs face a significant delay in the legal implementation of pharmacoeconomic guideline for assessment of BOMPs. The access to BOMPs is similar among the observed CEECs and the countries with the best access are Hungary and Greece. The influence of BOMP expenditures on the budget in the individual countries is significant.

National consumption of opioid and nonopioid analgesics in Croatia: 2007-2013

Background

The increased consumption of analgesics has been documented worldwide during the last 2 decades. The aim of the study was to examine the trends in opioid and nonopioid analgesic consumption in Croatia between 2007 and 2013.

Methods

Data on opioid consumption were extracted from the database of the national authority. All opioid and nonopioid analgesics were included in the analysis. Data were presented as defined daily doses per 1,000 inhabitants per day. Adequacy of opioid consumption was calculated using adequacy of consumption measure.

Results

During the examined 7-year period, the total consumption and total cost of all analgesics in Croatia showed continuous increase. In the M01A group (anti-inflammatory and antirheumatic products, nonsteroids), ibuprofen had an exponential increasing trend, and in 2011, it overtook diclofenac consumption. Ibuprofen and diclofenac had the highest consumption also in the M02A group of topical products for joint and muscular pain. Tramadol was by far the most consumed type of opioids (N02A group) and paracetamol in the group of other analgesics and antipyretics (N02B). The adequacy of consumption measure value was 0.19, indicating that Croatia is a country with a low opioid consumption.

Conclusion

Between 2007 and 2013, both consumption of analgesics and their cost in Croatia had an increasing trend. Comparisons with data from other countries, based on the published literature, indicate that analgesic consumption in Croatia is still relatively low. Calculation of the adequacy of opioid consumption indicated that Croatia is a country with low opioid consumption. Further studies are necessary for establishing whether current analgesic consumption in Croatia corresponds to patient needs.

Effect of head position on cerebrospinal fluid pressure in cats: comparison with artificial model

AIM

To demonstrate that changes in the cerebrospinal fluid (CSF) pressure in the cranial cavity and spinal canal after head elevation from the horizontal level occur primarily due to the biophysical characteristics of the CSF system, ie, distensibility of the spinal dura.

METHODS

Experiments in vivo were performed on cats and a new artificial model of the CSF system with dimensions similar to the CSF system in cats, consisting of non-distensible cranial and distensible spinal part. Measurements of the CSF pressure in the cranial and spinal spaces were performed in chloralose-anesthetized cats (n = 10) in the horizontal position on the base of a stereotaxic apparatus (reference zero point) and in the position in which the head was elevated to 5 cm and 10 cm above that horizontal position. Changes in the CSF pressure in the cranial and spinal part of the model were measured in the cranial part positioned in the same way as the head in cats (n = 5).

RESULTS

When the cat was in the horizontal position, the values of the CSF pressure in the cranial (11.9 +/- 1.1 cm H2O) and spinal (11.8 +/- 0.6 cm H2O) space were not significantly different. When the head was elevated 5 cm or 10 cm above the reference zero point, the CSF pressure in the cranium significantly decreased to 7.7 +/- 0.6 cm H2O and 4.7 +/- 0.7 cm H2O, respectively, while the CSF pressure in the spinal space significantly increased to 13.8 +/- 0.7 cm H2O and 18.5 +/- 1.6 cm H2O, respectively (P<0.001 for both). When the artificial CSF model was positioned in the horizontal level and its cranial part elevated by 5 cm and 10 cm, the changes in the pressure were the same as those in the cats when in the same hydrostatic position.

CONCLUSIONS

The new model of the CSF system used in our study faithfully mimicked the changes in the CSF pressure in cats during head elevation in relation to the body. Changes in the pressure in the model were not accompanied by the changes in fluid volume in the non-distensible cranial part of the model. Thus, it seems that the changes in the CSF pressure occur due to the biophysical characteristics of the CSF system rather than the displacement of the blood and CSF volumes from the cranium to the lower part of body.