F. Cankat Tulunay

Reversal of experimental neuropathic pain by T-type calcium channel blockers

Experimental nerve injury results in exaggerated responses to tactile and thermal stimuli that resemble some aspects of human neuropathic pain. Neuronal hyperexcitability and neurotransmitter release have been suggested to promote such increased responses to sensory stimuli. Enhanced activity of Ca2+ current is associated with increased neuronal activity and blockade of N‐ and P‐types, but not L‐type, calcium channels have been found to block experimental neuropathic pain. While T‐type currents are believed to promote neuronal excitability and transmitter release, it is unclear whether these channels may also contribute to the neuropathic state. Rats were prepared with L5/L6 spinal nerve ligation, and tactile and thermal hypersensitivities were established. Mibefradil or ethosuximide was administered either intraperitoneally, intrathecally (i.th.), or locally into the plantar aspect of the injured hindpaw. Systemic mibefradil or ethosuximide produced a dose‐dependent blockade of both tactile and thermal hypersensitivities in nerve‐injured rats; responses of sham‐operated rats were unchanged. Local injection of mibefradil also blocked both end points. Ethosuximide, however, was inactive after local administration, perhaps reflecting its low potency when compared with mibefradil. Neither mibefradil nor ethosuximide given i.th. produced any blockade of neuropathic behaviors. The results presented here suggest that T‐type calcium channels may play a role in the expression of the neuropathic state. The data support the view that selective T‐type calcium channel blockers may have significant potential in the treatment of neuropathic pain states.

Comparing policies to enhance prescribing efficiency in Europe through increasing generic utilization: changes seen and global implications

Aim: the aim of this article was to evaluate the influence of different demand-side measures to enhance the prescribing of generics in ambulatory care based on cross-national comparisons. Methods: an observational retrospective study was conducted using administrative databases from across Europe, documenting changes in reimbursed utilization and expenditure of different proton pump inhibitors (PPIs) and statins between 2001 and 2007, alongside different reforms to enhance prescribing efficiency. Utilization was converted to defined daily doses (DDDs) and expenditures were converted to euros. Demand-side measures were collated under the ‘4 Es’ – education, engineering, economics and enforcement – to enable comparisons on the nature and intensity of reforms between countries. Results: there were considerable differences in the utilization of generics and patent-protected PPIs and statins among Western European countries. Decreased utilization of omeprazole and simvastatin, alongside increased utilization of esomeprazole, atorvastatin and rosuvastatin, was seen in countries with limited demand-side measures to counteract commercial pressures. Prescribing restrictions, or a combination of education, prescribing targets and financial incentives, had the greatest influence on enhancing the utilization of omeprazole and simvastatin. For example, there was a threefold reduction in the utilization of atorvastatin in Austria following prescribing restrictions. Multiple demand-side interventions generally had a greater influence than single interventions, with the impact appearing additive. Multiple interventions coupled with initiatives to lower prices of generics considerably enhanced prescribing efficiency. Conclusion: this cross-national study has demonstrated considerable variation in the utilization and expenditure of PPIs and statins across Europe, providing opportunities to further improve prescribing efficiency. The ‘4 Es’ do provide an understandable methodology to document and compare the influence of different demand-side measures, with the influence varying by their extent and intensity. Further reforms are essential given current financial pressures. Consequently, further research will concentrate on the potential to develop a scoring system to help predict the possible impact of different demand-side measures on future utilization patterns.

Naloxone-induced or postwithdrawal abstinence signs in ?9-Tetrahydrocannabinol-Tolerant rats

Ten rats were injected s.c. with THC twice daily for 5 weeks in increasing doses. In the last 3 weeks they received 40 mg/kg THC in each administration. Ten control rats received the same amount of vehicle by the same route for the same period. The comparison of rectal temperatures of the first and fifteenth days showed that a very pronounced tolerance developed to the hypothermic effect of THC.The administration of naloxone on the 22nd and 31st days precipitated an opiatelike abstinence syndrome. The termination of the drug administration on the 35th day also produced a similar withdrawal syndrome.The most common signs of abstinence syndrome in THC-treated animals were teeth chattering, defecation, urination, dyspnea, and complete palpebral closure. Although the frequency of the incidence of the following signs were not high, they have been observed only in THC-treated animals: chewing, tremors on the face, escape behavior, jumping, eating of objects, biting of fingers, and sniffing.During abstinence, an increased locomotor activity was recorded by an activity-meter. Similarly, the total amount of excreted feces and urine was higher in the THC group than in the controls. Both abstinence scores and increased motility exhibited the peak in the 48th h of withdrawal.Some similarities between the effects of THC and morphine have been reviewed.

Policies to enhance prescribing efficiency in europe: findings and future implications.

Introduction: European countries need to learn from each other to address unsustainable increases in pharmaceutical expenditures. Objective: To assess the influence of the many supply and demand-side initiatives introduced across Europe to enhance prescribing efficiency in ambulatory care. As a result provide future guidance to countries. Methods: Cross national retrospective observational study of utilization (DDDs – defined daily doses) and expenditure (Euros and local currency) of proton pump inhibitors (PPIs) and statins among 19 European countries and regions principally from 2001 to 2007. Demand-side measures categorized under the “4Es” – education engineering, economics, and enforcement. Results: Instigating supply side initiatives to lower the price of generics combined with demand-side measures to enhance their prescribing is important to maximize prescribing efficiency. Just addressing one component will limit potential efficiency gains. The influence of demand-side reforms appears additive, with multiple initiatives typically having a greater influence on increasing prescribing efficiency than single measures apart from potentially “enforcement.” There are also appreciable differences in expenditure (€/1000 inhabitants/year) between countries. Countries that have not introduced multiple demand side measures to counteract commercial pressures to enhance the prescribing of generics have seen considerably higher expenditures than those that have instigated a range of measures. Conclusions: There are considerable opportunities for European countries to enhance their prescribing efficiency, with countries already learning from each other. The 4E methodology allows European countries to concisely capture the range of current demand-side measures and plan for the future knowing that initiatives can be additive to further enhance their prescribing efficiency.

Use of Generics—A Critical Cost Containment Measure for All Healthcare Professionals in Europe?

Pharmaceutical expenditures in ambulatory care rose rapidly in Europe in the 1990s and early 2000s. This was typically faster than other components of healthcare spending, leading to reforms to moderate future growth. A number of these centered on generic medicines with measures to lower reimbursed prices as well as enhance their prescribing and dispensing. The principal objective of this paper is to review additional measures that some European countries can adopt to further reduce reimbursed prices for generics. Secondly, potential approaches to address concerns with generics when they arise to maximize savings. Measures to enhance the prescribing of generics will also briefly be discussed. A narrative review of the extensive number of publications and associated references from the co-authors was conducted supplemented with known internal or web-based articles. In addition, health authority and health insurance databases, principally from 2001 to 2007, were analyzed to assess the impact of the various measures on price reductions for generic omeprazole and generic simvastatin vs. pre-patent loss prices, as well as overall efficiency in Proton Pump Inhibitor (PPI) and statin prescribing. The various initiatives generally resulted in considerable lowering of the prices of generics as well as specifically for generic omeprazole and generic simvastatin vs. pre-patent loss prices. At one stage in the UK, generic simvastatin was just 2% of the originator price. These measures also led to increased efficiency for PPI and statin prescribing with reimbursed expenditure for the PPIs and statins either falling or increasing at appreciably lower rates than increases in utilization. A number of strategies have also been introduced to address patient and physician concerns with generics to maximize savings. In conclusion, whilst recent reforms have been successful, European countries must continue learning from each other to fund increased volumes and new innovative drugs as resource pressures grow. Policies regarding generics and their subsequent impact on reimbursement and utilization of single sourced products will continue to play a key role to release valuable resources. However, there must continue to be strategies to address concerns with generics when they exist.

Information processing components of the auditory event related potential are reduced by cocaine

The effects of cocaine on a human electroencephalographic event related potential (ERP) were measured. Forty-eight subjects received one of three IV doses (0.2, 0.4, or 0.6 mg/kg) and placebo. Thirty-three subjects received one of three oral doses (2, 3, or 4 mg/kg). All IV and oral doses reduced amplitude of the auditory ERP P200 and P300 components during the oddball task. P200 latency decreased. N100 amplitude was reduced only after IV administration. The changes in ERPs occurred during the period of peak cardiovascular and subjective effects.The amplitude reduction in ERP components occurring before the P300 component is consistent with decrements in attention, specifically selective attention. The P300 amplitude reduction after cocaine suggests a disruption of stimulus evaluation resources. The findings are inconsistent with the notion that stimulants affect only response selection and execution. The degree to which stimulants alter cognitive processes prior to response selection may depend on the magnitude of the cardiovascular, subjective, and probably other noncognitive effects.

The local antinociceptive actions of nonsteroidal antiinflammatory drugs in the mouse radiant heat tail-flick test

BACKGROUND:While many preclinical models detect the analgesic activity of nonsteroidal antiinflammatory drugs (NSAIDs), the radiant heat tail-flick response has repeatedly been insensitive to this class of drugs. As the tail-flick test involves nociceptive processing at spinal circuits with supraspinal modulation, it seems reasonable to assume that the NSAIDs should not modify strong nociceptive stimuli, since the primary site of action of NSAIDs is likely to be in the periphery. METHODS:We injected 3–300 &mgr;g of diclofenac, dipyrone, ketorolac, lysine acetyl salicylate, and sodium salicylate intradermally into mice tails and evaluated the tail-flick response to radiant heat. These results were compared with intraperitoneally injected controls. We also evaluated the ability of naloxone to reverse the observed effects. RESULTS:Intradermal injection of each NSAID produced a dose-dependent increase in tail-flick latency. Intraperitoneal NSAIDs injection produced no antinociceptive effects. Naloxone pretreatment had no effect on the antinociceptive effects of intradermal diclofenac, ketorolac, lysine acetyl salicylate, and sodium salicylate. Naloxone completely blocked the antinociceptive effects of intradermal dipyrone. CONCLUSIONS:Local, but not systemic, administration of NSAIDs produced antinociception in the tail-flick thermal assay. The endogenous opioid system contributes to the peripheral antinociceptive effects of dipyrone, but not to that of diclofenac, ketorolac, lysine asetyl salicylate, or sodium salicylate, suggesting differences in the mechanisms of action among the NSAIDs.

Pharmacological characterization of metamizol-induced relaxation in phenylephrine-precontracted rabbit thoracic aorta smooth muscle.

Metamizol produced a dose- and time-dependent relaxation in rabbit thoracic aorta smooth muscle that was precontracted by phenylephrine. Such a relaxation was not observed with indomethacin, which is also a nonsteroidal anti-inflammatory drug. The relaxing effect of metamizol was independent of the presence of vascular endothelium. Tetraethylammonium (a calcium-activated potassium channel inhibitor), glybenclamide (an ATP-dependent potassium channel inhibitor), indomethacin (a cyclooxygenase inhibitor), and methylene blue (a soluble guanylate cyclase inhibitor) did not have any effect on metamizol-induced relaxation response. Metamizol did not produce any relaxation effect on aortic smooth muscle when KCl (30, 60, and 117 mM KCl) was used instead of phenylephrine to precontract the preparation. Ouabain (a Na-K ATPase pump inhibitor) showed a dose-dependent inhibition on metamizols relaxation response. However, in potassium-free medium, which is an alternative way to block the Na-K ATPase pump, no inhibition in metamizol-induced relaxation response was observed. When metamizol was incubated for 2 h in organ-bath conditions before evaluating its relaxing effect, it produced a relatively faster relaxation, indicating that the relaxing effect of metamizol is produced by one of its (active) spontaneous degradation products (possibly 4-methylaminoantipyrine).

Characteristics of headache in migraine without aura and episodic tension-type headache in the Turkish population according to the IHS classification

We evaluated the characteristics of headache in migraine without aura and episodic tension-type headache diagnosed according to the International Headache Society (IHS) Classification. Fifty migraine without aura and 50 tension-type headache patients were selected prospectively. Fifty-eight percent of migraineurs had pain of a pulsating quality; 88% had severe pain and 74% had unilateral pain; aggravation by routine physical activity was reported by 96%. Episodic tension-type headache was of a pressing quality in 52%, moderate in 40%, bilateral in 82% and aggravated by routine physical activity in 16%. Nausea and/or vomiting, photophobia and phonophobia were reported significantly more commonly in migraineurs than tension-type headache patients.

The effects of morphine and Δ-9-tetrahydrocannabinol on motor activity in rats

Acute treatment of rats either by high doses of morphine or Δ9-tetrahydrocannabinol (THC) decreased locomotor activity. Naloxone reversed morphine-induced depression completely and reversed THC-induced depression only partially. On day 3 of treatment, tolerance developed to the locomotor inhibitory action of THC or morphine and partial cross-tolerance was observed to the depressant action of THC. Naloxone slightly depressed locomotor activity in THC-tolerant rats, but increased motor activity in morphine-tolerant rats.