The use and potential abuse of anticholinergic antiparkinson drugs in Norway: a pharmacoepidemiological study

Intravenous diclofenac and orphenadrine for the treatment of postoperative pain after remifentanil-based anesthesia : A double-blinded, randomized, placebo-controlled study

BACKGROUND

Postoperative intravenous diclofenac reduces patient opioid demand and is commonly used in surgical units. Orphenadrine is mainly used in combination with diclofenac for musculoskeletal injuries and postoperative pain control. The objective of this study was to compare the analgesic efficacy of diclofenac-orphenadrine, diclofenac alone and saline.

METHODS

We performed a double-blind, randomized, placebo-controlled, parallel-group, single-center clinical study investigating the opioid-sparing effect of a combination of diclofenac and orphenadrine versus diclofenac alone versus isotonic saline solution. Initially 72 patients were included and received total intravenous anesthesia during cruciate ligament surgery. All patients were postoperatively treated with a patient-controlled analgesia (PCA) device containing hydromorphone. Pharmacological safety was assessed by laboratory parameters, vital signs, and delirium detection scores.

RESULTS

There was no significant difference between the groups in cumulative dose of PCA analgesics required after 24 h postsurgery, with 5.90 mg (SD ± 2.90 mg) in the placebo group, 5.73 mg (SD ± 4.75 mg) in the diclofenac group, and 4.13 mg (SD ± 2.57 mg) in the diclofenac-orphenadrine group. Furthermore, there was no significant difference between the groups in cumulative dose of PCA analgesics required 2 h postsurgery (n = 65). Mean dose of hydromorphone required after 2 h was 1.54 mg (SD ± 0.57 mg) in the placebo group, 1.56 mg (SD ± 1.19 mg) in the diclofenac-only group, and 1.37 mg (SD ± 0.78 mg) in the diclofenac-orphenadrine group. However, when comparing the diclofenac-orphenadrine group and the diclofenac group combined to placebo there was a significant reduction in PCA usage in the first 24 h postsurgery. In total, there were 25 adverse events reported, none of which were rated as severe.

CONCLUSION

Orphenadrine-diclofenac failed to significantly reduce postoperative opioid requirements. However, in an exploratory post hoc analysis the diclofenac-orphenadrine and the diclofenac group combined versus placebo showed a tendency to reduce opioid demand in postoperative pain control. Further research is required to determine the value of orphenadrine as an adjuvant in a multimodal approach for postoperative pain management.

Does the Anticholinergic Drug Biperiden Affect Early Neural Tube Development in Chick Embryos?

Objective: Biperiden (BPD) is an anticholinergic agent that acts both centrally and peripherally. It is used to counteract both extrapyramidal side effects of neuroleptic treatment and symptoms of Parkinson’s disease in clinical practice. Current study was layout to determine the potential toxic effect of different doses of Biperiden on neural tube closure in 48 hour chick embryos. Methods: Sixty fertilized eggs were used in the study. All eggs were placed in the incubator and divided into four groups (15 eggs in each); control, BPD 1, BPA 2 and BPD 3. At 28 hr of incubation, three different doses of biperiden were administered subblastodermically. At the end of 48 hr of incubation, all eggs were opened and embryos were dissected and evaluated morphologically and histopathologically. Results: According to these results, the mean crown-rump length and somite number tended to decrease proportionally with the dose. As the dose increases, the number of open neural tube and undeveloped embryos in the experimental groups also increases. There was also a significant difference between the groups in terms of Hamburger-Hamilton stages of embryos evaluated according to the number of somite. Embryos in the control, BPD 1 and BPD 2 groups were observed at stage 13, and those in the BPD 3 group were observed at stage 12. Conclusion: These results showed that Biperiden even in the low dose has teratogenicity on neural tube closure in early chick embryos. The somite numbers and crown-rump length were decreased depending on the dose and Biperiden caused developmental retardation in high doses.

Treatment initiation for parkinson’s disease in Australia 2013–2018: a nation-wide study

Background

Guidelines highlight the importance of an individualized approach to treatment initiation for Parkinson’s disease. Our aim was to investigate initiation of anti-Parkinson medication in Australia from 2013–2018, and to determine factors predicting choice of initial treatment.

Methods

Cohort of new-users (N = 4,887) of anti-Parkinson medication aged ≥ 40 years were identified from a 10% random representative sample of national medication dispensing data from July-2013 to June-2018. Changes in treatment initiation were examined across the whole cohort and stratified by age and sex.

Results

Treatment initiation was most frequent with levodopa followed by non-ergot dopamine agonists (DAs) and anticholinergics. Two thirds initiated with levodopa across the study period. Initiation with non-ergot DAs increased from 22 to 27% (rate ratio, RR 1.23, 95% confidence interval, CI 1.02–1.47) and initiation with anticholinergics decreased from 6.9% to 2.4% (RR 0.34, 95% CI 0.21–0.55) from 2013–2018. Among persons aged ≥ 65 years, one third of women and one fourth of men initiated on levodopa. Among women aged < 65 years, rates of treatment initiation with DAs (37%) and levodopa (37%) were similar in 2013/2014 but initiation with DA exceeded levodopa thereafter. Among men aged < 65 years, treatment initiation with levodopa (44%-49%) remained more frequent than initiation with DAs (29%-32%) throughout the study period.

Conclusions

Treatment initiation with levodopa was most frequent among persons aged ≥ 65 years, consistent with current guidelines. Whilst the value of levodopa sparing strategies is unclear, treatment initiation with DA has become increasingly common relative to levodopa among women but not among men aged < 65 years.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-022-03095-3.

Misuse of Anticholinergic Medications: A Systematic Review

(1) Background: Over the last decade, misuse and diversion of medications has appeared to be increasingly concerning phenomena, including a range of different molecules. As current knowledge on the abuse of centrally acting anticholinergics is limited, the aim of the present study is to review the relevant published data, focusing on the following molecules: benztropine, biperiden, scopolamine, orphenadrine, and benzhexol/trihexyphenidyl (THP). (2) Methods: A systematic literature review was carried out using Pubmed, Scopus, and Web of Science databases following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Research methods were registered on PROSPERO (CRD42021257293). (3) Results: A total of 48 articles, including case reports, surveys, and retrospective case series analyses, were included. Most articles focused on benzhexol/THP (n = 25), and benztropine (n = 4). The routes of administration were mostly oral, and macrodoses together concomitant illicit drugs, e.g., cocaine, have been recorded. Toxidromes included both physical (e.g., tachycardia, tachypnoea, dilatated pupils, dry skin, urinary retention, ataxia, etc.) and psychiatric symptoms (e.g., anxiety, agitation, delirium, etc.). Fatal outcomes were very rare but reported. (4) Conclusion: Results from the present study show that anticholinergic misusing issues are both widespread worldwide and popular. Considering the potential adverse effects associated, healthcare professionals should be vigilant and monitor eventual misusing issues.

Assessment of gabapentin misuse using prescription drug monitoring program data

BACKGROUND

Gabapentin is an anticonvulsant medication with potential misuse reported in case reports and population studies, highlighting the need to reexamine its abuse liability. The purpose of this study was to describe gabapentin dispensing patterns and assess potential misuse. Methods: We used data from Ohio's Prescription Drug Monitoring Program (PDMP) from December 1, 2016 to March 31, 2017 and restricted the population to adults who filled at least one gabapentin prescription (N = 379,372). Gabapentin dispensing patterns are described and multiple strategies were used to assess potential misuse, including Lorenz-1 curve analysis. Supratherapeutic dosing, number of prescribers and number of pharmacies used were compared for individuals who were co-dispensed medications for opioid use disorder (MOUD) and those who were not. Results: More than one million gabapentin prescriptions were dispensed during the 4-month period, with a mean dose of 1103.8 mg. While few individuals received supratherapeutic dosing, exceptionally high doses were observed. Half of the individuals (50.9%) were co-dispensed gabapentin and opioids. The Lorenz-1 value for gabapentin (5.5%) did not exceed the threshold for misuse potential. Individuals co-dispensed MOUD were more likely to have supratherapeutic dosing; however, they had a lower Lorenz-1 value compared to individuals not co-dispensed MOUD. Conclusions: Among Ohio residents dispensed gabapentin, there was no evidence of misuse using PDMP data based on the Lorenz-1 value, yet supratherapeutic dosing of gabapentin was observed and was associated with OUD. New strategies may be needed to identify the non-medical use of gabapentin.

The definition and measurement of heterogeneity

Heterogeneity is an important concept in psychiatric research and science more broadly. It negatively impacts effect size estimates under case-control paradigms, and it exposes important flaws in our existing categorical nosology. Yet, our field has no precise definition of heterogeneity proper. We tend to quantify heterogeneity by measuring associated correlates such as entropy or variance: practices which are akin to accepting the radius of a sphere as a measure of its volume. Under a definition of heterogeneity as the degree to which a system deviates from perfect conformity, this paper argues that its proper measure roughly corresponds to the size of a system's event/sample space, and has units known as numbers equivalent. We arrive at this conclusion through focused review of more than 100 years of (re)discoveries of indices by ecologists, economists, statistical physicists, and others. In parallel, we review psychiatric approaches for quantifying heterogeneity, including but not limited to studies of symptom heterogeneity, microbiome biodiversity, cluster-counting, and time-series analyses. We argue that using numbers equivalent heterogeneity measures could improve the interpretability and synthesis of psychiatric research on heterogeneity. However, significant limitations must be overcome for these measures-largely developed for economic and ecological research-to be useful in modern translational psychiatric science.

[Antipsychotic-induced motor symptoms in schizophrenic psychoses-Part 1 : Dystonia, akathisia und parkinsonism]

Acute antipsychotic-induced movement disorders (AIMD) are clinically relevant since they are frequently associated with high subjective distress, and since over the long-term they can negatively impact treatment adherence of patients with schizophrenic psychoses. This review article summarizes the relevant studies on the prevalence, risk factors, prevention and treatment options and instruments for early prediction of acute AIMD in schizophrenic psychoses. The current evidence and treatment recommendations are divided into three main areas: acute dystonia, akathisia, and parkinsonism. For the treatment of acute dystonia trihexyphenidyl and biperiden have shown their efficacy. Considering pharmacological treatment of akathisia, there is some preliminary evidence for medication with lipophilic beta-receptor blockers (propranolol and pindolol), clonidine, benzodiazepines, mianserin, mirtazapine und trazodone. The treatment options for drug-induced parkinsonism include reduction or switching from one antipsychotic to another with a lower affinity for dopamine D₂ receptors, amantadine or in the regular administration of anticholinergic drugs. In conclusion, acute AIMD is easily to recognize but is not always effectively and durably treated. Early recognition and treatment of acute AIMD could be associated with improved treatment outcomes.

Blockade of muscarinic acetylcholine receptors facilitates motivated behaviour and rescues a model of antipsychotic-induced amotivation

Disruptions to motivated behaviour are a highly prevalent and severe symptom in a number of neuropsychiatric and neurodegenerative disorders. Current treatment options for these disorders have little or no effect upon motivational impairments. We assessed the contribution of muscarinic acetylcholine receptors to motivated behaviour in mice, as a novel pharmacological target for motivational impairments. Touchscreen progressive ratio (PR) performance was facilitated by the nonselective muscarinic receptor antagonist scopolamine as well as the more subtype-selective antagonists biperiden (M1) and tropicamide (M4). However, scopolamine and tropicamide also produced increases in non-specific activity levels, whereas biperiden did not. A series of control tests suggests the effects of the mAChR antagonists were sensitive to changes in reward value and not driven by changes in satiety, motor fatigue, appetite or perseveration. Subsequently, a sub-effective dose of biperiden was able to facilitate the effects of amphetamine upon PR performance, suggesting an ability to enhance dopaminergic function. Both biperiden and scopolamine were also able to reverse a haloperidol-induced deficit in PR performance, however only biperiden was able to rescue the deficit in effort-related choice (ERC) performance. Taken together, these data suggest that the M1 mAChR may be a novel target for the pharmacological enhancement of effort exertion and consequent rescue of motivational impairments. Conversely, M4 receptors may inadvertently modulate effort exertion through regulation of general locomotor activity levels.

Use of power-law analysis to predict abuse or diversion of prescribed medications: proof-of-concept mathematical exploration

OBJECTIVE

To conduct a proof-of-concept study comparing Lorenz-curve analysis (LCA) with power-law (exponential function) analysis (PLA), by applying segmented regression modeling to 1-year prescription claims data for three medications-alprazolam, opioids, and gabapentin-to predict abuse and/or diversion using power-law zone (PLZ) classification.

RESULTS

In 1-year baseline observation, patients classified into the top PLZ groups (PLGs) were demographically and diagnostically similar to those in Lorenz-1 (top 1% of utilizers) and Lorenz-25 (top 25%). For prediction of follow-up (6-month post-baseline) Lorenz-1 use of alprazolam and opioids (i.e., potential abuse/diversion), PLA had somewhat lower sensitivity compared with LCA (83.5-95.4% vs. 99.5-99.9%, respectively) but better specificity (98.2-98.8% vs. 75.5%) and much better positive predictive value (PPV; 34.5-45.3% vs. 4.0-4.6%). Of top-PLG alprazolam- and opioid-treated patients, respectively, 20.7 and 9.9% developed incident (new) Lorenz-1 in followup, compared with < 3% of Lorenz-25 patients. For gabapentin, neither PLA nor LCA predicted incident Lorenz-1 (PPV = 0.0-1.4%). For all three medications, PLA sensitivity for follow-up hospitalization was < 5%, but specificity was better for PLA (97.3-99.2%) than for LCA (74.3-75.4%). PLA better identified patients at risk of future controlled substance abuse/diversion than did LCA, but the technique needs refinement before widespread use.

Harmonizing post-market surveillance of prescription drug misuse: a systematic review of observational studies using routinely collected data (2000-2013)

BACKGROUND

Prescription drug misuse is a growing public health concern globally. Routinely collected data provide a valuable tool for quantifying prescription drug misuse.

OBJECTIVE

To synthesize the global literature investigating prescription drug misuse utilizing routinely collected, person-level prescription/dispensing data to examine reported measures, documented extent of misuse and associated factors.

METHODS

The MEDLINE, EMBASE, CINAHL, MEDLINE In Process, Scopus citations and Google Scholar databases were searched for relevant articles published between 1 January 2000 and 31 July 2013. A total of 10,803 abstracts were screened and 281 full-text manuscripts were retrieved. Fifty-two peer-reviewed, English-language manuscripts met our inclusion criteria-an aim/method investigating prescription drug misuse in adults and a measure of misuse derived exclusively from prescription/dispensing data.

RESULTS

Four proxies of prescription drug misuse were commonly used across studies: number of prescribers, number of dispensing pharmacies, early refills and volume of drugs dispensed. Overall, 89 unique measures of misuse were identified across the 52 studies, reflecting the heterogeneity in how measures are constructed: single or composite; different thresholds, cohort definitions and time period of assessment. Consequently, it was not possible to make definitive comparisons about the extent (range reported 0.01-93.5 %), variations and factors associated with prescription drug misuse.

CONCLUSIONS

Routine data collections are relatively consistent across jurisdictions. Despite the heterogeneity of the current literature, our review identifies the capacity to develop universally accepted metrics of misuse applied to a core set of variables in prescription/dispensing claims. Our timely recommendations have the potential to unify the global research field and increase the capacity for routine surveillance of prescription drug misuse.

Effects of biperiden on the treatment of cocaine/crack addiction: a randomised, double-blind, placebo-controlled trial

Cocaine use affects approximately 13.4 million people, or 0.3% of the world's population between 15 and 64 years of age. Several authors have described drug addiction as a disease of the brain reward system. Given that the cholinergic system impacts reward mechanisms and drug self-administration, acetylcholine (ACh) might play an important role in the cocaine addiction process. We evaluated the efficacy of biperiden (a cholinergic antagonist) in reducing craving and the amount used, and in increasing compliance with treatment for cocaine/crack addiction. It was a study double-blind, randomised, placebo-controlled, 8-week trial of 111 cocaine or crack addicted male patients between 18 and 50 years old. Two groups were compared: placebo (n=55) or biperiden (n=56) combined with weekly sessions of brief group cognitive-behavioural therapy. The efficacy of treatment was evaluated according to the patients' compliance and several instruments: the Minnesota Cocaine Craving Scale, the Beck Depression and Anxiety Scales and a questionnaire assessing the amount of drug used. All of the patients attended weekly sessions for two months. We analysed the data considering the patients' intention to treat based on our last observation. Of the 56 patients in the biperiden group, 24 completed the treatment (42.8%) compared with only 11 patients in the placebo group (20%), which was a significant difference (p=0.009). Compliance with treatment was 118% higher in the biperiden group, which was also the group that presented a statistically significant reduction in the amount of cocaine/crack use (p<0.001). There was statistically significant difference between the craving score in the biperiden group. Pharmacological blockade of the cholinergic system with biperiden is a promising alternative to treat cocaine/crack addiction, helping patients to reduce the amount used and improving compliance with psychotherapy treatment.

Intravenous Abuse of Tropicamide in Opioid Use Disorder: Presentation of 2 Cases

BACKGROUND

Tropicamide is an antimuscarinic ophthalmic solution used to produce short-acting mydriasis and cycloplegia. Topical abuse of ophthalmic solutions has been reported, but intravenous (IV) abuse of tropicamide seems to be a new phenomenon.

CASES

The authors present 2 patients with concomitant IV tropicamide abuse and opioid use disorder. Patients were hospitalized and started on buprenorphine/naloxone treatment for opioid withdrawal. Patients' reports about tropicamide effects are remarkable, as they claimed that tropicamide increased the efficacy of heroin while decreasing and delaying the withdrawal symptoms.

DISCUSSION

Although anticholinergics have been known to be abused for their euphoric effects, these cases' motivation to use tropicamide seemed to extend beyond its euphoric effect and was also based on its interaction with heroin. It is feared that tropicamide abuse may become more frequent. Health professionals should be aware of this trend so that symptoms of misuse and intoxication can be recognized, and ophthalmologists should consider the abuse potential of anticholinergic eye drops when prescribing them.

The potency and efficacy of anticholinergics to inhibit haloperidol-induced catalepsy in rats correlates with their rank order of affinities for the muscarinic receptor subtypes

Extrapyramidal syndromes (EPS) caused by antipsychotic therapy are currently treated with anticholinergics that lack selectivity for the five muscarinic receptor subtypes. Since these receptors are heterogeneously expressed among the different classes of striatal neurons and their afferents, it can be expected that their simultaneous blockade will cause distinct, sometimes opposed, effects within the striatal circuitry. In order to test the hypothesis that the differential blockade of the muscarinic receptor subtypes would influence their potency and efficacy to prevent EPS, here we tested four anticholinergics with varying order of affinities for the muscarinic receptor subtypes, and compared their dose-response curves to inhibit haloperidol-induced catalepsy in male rats. Drugs were applied into the lateral ventricle 15 min before haloperidol (2 mg/kg, s.c.). Catalepsy was measured in the bar test at 15 min intervals during 5 h. The preferential M1/M4 antagonist pirenzepine (3, 10, 30, 100, and 300 nmol) caused a dose-dependent inhibition of catalepsy intensity: ED50 = 5.6 nmol [95% CI, 3.9-8.1], and latency: ED50 = 5.6 nmol [95% CI, 3.7-8.6]. Pirenzepine had the steepest dose-response curve, producing maximal inhibition (84 ± 5%) at the dose of 10 nmol, while its effect tended to reverse at higher doses (62 ± 11%). The purported M1/M3 antagonist 4-DAMP (30, 100, and 300 nmol) also caused a dose-dependent inhibition of catalepsy intensity: ED50 = 29.5 nmol [95% CI, 7.0 to 123.0], and latency: ED50 = 28.5 nmol [95% CI, 2.2 to 362.0]. However, the curve for 4-DAMP had a less pronounced slope, reaching its maximal effect (63 ± 14%) at the dose of 300 nmol. The M2/M4 antagonist AF-DX 116 (10, 30, and 300 nmol) only caused a partial inhibition of catalepsy (30 ± 11%) at the dose of 30 nmol, but this changed to a non-significant increment (15 ± 10%) at the dose of 100 nmol. The alleged M4 antagonist tropicamide (30, 100, 300, and 600 nmol) produced a partial inhibition of catalepsy (36 ± 12%) at the dose of 300 nmol, but lacked effect at higher or lower doses. Concurrent treatment with pirenzepine (10 nmol) and tropicamide (300 nmol) produced an effect similar to that of tropicamide alone. The greater potency and efficacy of pirenzepine for catalepsy inhibition could be due to its higher affinity for M1 receptors and, to a lesser extent, for M4 receptors. It is suggested that selective M1 antagonists would be more effective than M2, M3 or M4 antagonists to prevent EPS caused by antipsychotic drugs.

Biperiden for treatment of somnambulism in adolescents and adults with or without epilepsy: clinical observations

BACKGROUND

Sleepwalking in adolescents and adults may lead to serious injuries and require treatment. Anecdotal treatment recommendations include benzodiazepines (which also work in focal seizures of the frontal lobe that are an important differential diagnosis), imipramine and amitriptyline.

METHODS

We assessed in a follow-up study of 4 years (medium, range: 2-7 years) the usefulness of the antiparkinsonian drug biperiden (Akineton©), an acetylcholine antagonist with high affinity for muscarinic M1-type receptors, in four consecutive cases of arousal disorder with sleepwalking and confusional behavior in adolescents and adults with or without epilepsy who did not respond to diazepam, clonazepam or amitriptyline.

FINDINGS

The adjunctive use of biperiden was associated with reduction or remission of sleepwalking episodes in four consecutive treatment-refractory cases of arousal disorder with sleepwalking and confusional behavior. In contrast, biperiden showed no effect in a patient with REM behavioral disorder.

INTERPRETATION

Although our observations do not and cannot establish the efficacy or safety of biperiden, it may be useful to consider biperiden for treatment of sleepwalking, if needed. A putative cholinergic mechanism of arousal disorders, including sleepwalking, provides a reasonable hypothesis why the anticholinergic agent biperiden might work. Evidence for efficacy and safety from randomized controlled trials is needed to confirm our preliminary observations.

Biperiden dependence: case report and literature review

Anticholinergic drugs are frequently used in psychiatry for the prophylaxis and treatment of extrapiramidal symptoms caused by neuroleptics. Abuse of anticholinergic agents has been reported in patients with psychotic disorders, on treatment with neuroleptics, and polysubstance use disorders. We are reporting the case of a patient who presented with hypoactive delirium as a consequence of biperiden dependence. The clinician must pay special attention to detect anticholinergic misuse in patients presenting with delirium of unknown cause.

Misuse of medicines in the European Union: a systematic review of the literature

BACKGROUND

Although awareness of the misuse of medicines is increasing, data on the extent of the problem in the European Union (EU) are lacking.

METHODS

In order to assess the magnitude and severity of the problem, a systematic review of the literature on the misuse of analgesics, opioid substitution medicines and sedatives/hypnotics (with the exception of benzodiazepines) was conducted using the PubMed and Web of Science databases. Relevant literature was identified between 2001 and 2011.

RESULTS

The main groups of misused medicines include opioid analgesics, methadone, buprenorphine and Z-drugs. Regional trends in medicine misuse indicate heterogeneity across the EU with respect to misused medicine types and research activities. Prevalence, high-risk populations and factors contributing to medicine misuse are discussed.

CONCLUSION

The implications of these findings for prevention, treatment, and policy in the EU are considered.

[Post-marketing surveillance systems for psychoactive prescription drug abuse]

Drugs affecting the central nervous system form a unique group of products for surveillance because they could be misused, abused or diverted. Considering the characteristics of this behaviour that is often concealed, specific post-marketing surveillance systems have been developed to monitor abuse of prescription drugs in some countries. The purpose of this review is to list and to describe post-marketing surveillance systems, according their methodology, in France and in foreign countries. These programs are based on adverse effect notifications, medical or legal consequences of abuse, general or specific population-based survey, professional networks or medication databases. Some programs use simultaneously several information sources. In conclusion, the multifaceted nature, the diversity and the inventiveness of post-marketing surveillance systems reflects the complexity of the abuse issue.

Utilization of anti-Parkinson drugs in Australia: 1995-2009

PURPOSE

To examine trends in the prescribing of anti-Parkinsonian drugs (APD) in Australia from 1995 to 2009.

METHODS

We analyzed the Medicare Australia and Drug Utilisation Sub-Committee (DUSC) databases for prescription data for overall APD dispensed use from 1995. We were able to examine prescribing by gender, age, and type of prescriber between 2002 and 2009. Prescriptions were converted to defined daily doses (DDD)/1000 population/day using Australian Bureau of Statistics population data.

RESULTS

Dispensed use of levodopa + carbidopa remained steady from 1995 to 2009 (0.76-0.82 DDD/1000 population/day); levodopa + benserazide use increased from 0.34 to 0.55 DDD/1000 population/day. Since 2005 dispensed use of levodopa + carbidopa + entacapone has steadily increased, from 0.03 to 0.10 DDD/1000 population/day. In July 2009 levodopa + carbidopa was the most widely used agent, followed by levodopa + benserazide, then benztropine. Cabergoline increased from 1999, peaked in 2006, and thereafter declined. APD use peaked in males and females aged 60-69 years. Age-adjusted utilization was slightly higher in males than females.

CONCLUSIONS

The amount of levodopa dispensed has slowly increased with levodopa + benserazide increasing faster than levodopa + carbidopa. Use of cabergoline fell when pramipexole became available and the risk of ergot-related serosal adverse effects was more widely appreciated. Use of centrally acting anti-cholinergics decreased over a period of time when use of atypical anti-psychotic agents increased.

Synergism of theophylline and anticholinergics to inhibit haloperidol-induced catalepsy: a potential treatment for extrapyramidal syndromes

Extrapyramidal syndromes (EPS) impose a heavy burden on patients receiving antipsychotic therapy. Anticholinergics are the drugs of choice for preventing EPS, but they also produce many adverse reactions. Using the EPS model of haloperidol-induced catalepsy we evaluated the potential therapeutic value of a mixture of low doses of the non-selective adenosine antagonist theophylline (0.93 and 1.86 mg/kg), and the muscarinic antagonists benztropine (0.134 and 0.268 mg/kg) and ethopropazine (0.116 and 0.232 mg/kg). In rats pretreated with vehicle (distilled water), the cumulative catalepsy time over 5 h was 4199±228 s, and the mean latency was 67.5±7.8 min. Applied separately, neither of the drugs at the doses used caused significant changes of catalepsy intensity vs. control rats. However, the combination of the larger doses of theophylline and benztropine caused a significant reduction of catalepsy intensity (-41±10%) compared with the effects of the vehicle, vs. the lower dose of benztropine, and vs. both doses of theophylline alone. The mixture of the larger doses of theophylline and benztropine also delayed catalepsy onset (156±21 min) as compared with the lower doses of these same drugs applied alone. In the case of theophylline plus ethopropazine, only the association of the larger doses showed a non-significant tendency to inhibit catalepsy (-21±8%) and to prolong its latency (108±13 min). Further, neither catalepsy intensity nor its latency was affected by a combination of the selective A(1)R antagonist DPCPX (1 mg/kg), with the larger doses of both anticholinergics. In contrast, the anticholinergics showed synergism with a subthreshold dose of the selective A(2A)R antagonist ZM 241395 (0.5 mg/kg), causing a significant reduction of catalepsy intensity (ethopropazine, -27±5%; benztropine, -35±9%) and prolonging its latency (ethopropazine, 65±9 min; benztropine, 78±11 min), compared with the effect of their respective vehicle (DMSO plus mineral oil: catalepsy time, 5100±196 s; latency, 17.5±2.5 min). These findings suggest that neuroleptic-induced EPS could be effectively controlled by a combination of lower doses of theophylline and anticholinergics, with the advantage of maximizing their efficacy and minimizing their adverse reactions.

The use of antipsychotic and anticholinergic antiparkinson drugs in Norway after the withdrawal of orphenadrine

AIMS

Extrapyramidal side-effects induced by antipsychotic drugs are treated with dose reduction or substitution with another antipsychotic drug or by the addition of anticholinergic antiparkinson agents. The withdrawal of orphenadrine from the Norwegian market provided a possibility to investigate to what degree these alternative measures were taken in clinical practice.

METHODS

Data were drawn from the Norwegian Prescription Database on the sales of antipsychotics and one of the two anticholinergic antiparkinson agents marketed in 2004, orphenadrine and biperiden, to a total of 39 758 outpatients. The patients were reinvestigated in 2007. The consequences of the withdrawal of orphenadrine from the Norwegian market in 2005 regarding dosing, switching and cessation of antipsychotics and use of anticholinergics were assessed for orphenadrine users compared with biperiden users.

RESULTS

Of the patients originally using orphenadrine, 28.4% stopped using the drug without reducing the antipsychotic dose or replacing orphenadrine with another anticholinergic agent. The corresponding number for biperiden users was 19.3%. Only 11.8% of patients switched to another antipsychotic drug, but they used significantly lower antipsychotic doses than those who stayed on the same drug.

CONCLUSION

The use of anticholinergic antiparkinson agents could be seen as superfluous for at least one-third of patients.