ABSTRACT
BACKGROUND: Opioid prescribing/dispensing data can inform policy surrounding regulation by informing trends and types of opioid prescribed and geographic variations. In Australia so far only partial data on dispensing have been published, and data for states/territories remain unknown. AIM: Using a range of measures, this study examines 20-year (1992-2011) trends in prescription opioid analgesics in Australia - both nationally and for individual jurisdictions. METHODS: Dispensing data were obtained from the Drug Utilisation Sub-Committee and the Pharmaceutical Benefits Scheme (PBS) websites. Trends in numbers of prescriptions and daily defined dose (DDD)/1000 people/day were examined over time and across states/territories. Seasonal variations in PBS/Repatriation Pharmaceutical Benefits Scheme (RPBS) items for nationwide dispensing were adjusted using a centred moving smoothing technique. RESULTS: In two decades, 165.32 million prescriptions for opioids were dispensed, with codeine and its derivatives the most prescribed formulation (50.1%) followed by tramadol (13.5%) and oxycodone derivatives (12.7%). In terms of DDD/1000 people/day, dispensing increased from 5.38 in 1992 to 14.46 in 2011. There are significant increasing trends for total, PBS/RPBS and under co-payment prescriptions (priced below patient co-payment). The DDD/1000 people/day for items dispensed through PBS/RPBS was highest in Tasmania. CONCLUSION: Prescription opioid dispensing increased substantially over the study period. With an ageing population, this trend is likely to continue in future. A growing concern about harms associated with opioid use warrants balanced control measures so that harms could be minimised without reducing effective pain treatment. Research examining utilisation in small geographic areas may help design spatially tailored interventions. A real-time drug-monitoring programme may reduce undue prescribing and dispensing.
Subject(s)
Analgesics, Opioid/administration & dosage , Drug Prescriptions/statistics & numerical data , Drug Utilization/trends , Pain/drug therapy , Pain/epidemiology , Australia/epidemiology , Humans , Pain Management , Practice Patterns, Physicians'ABSTRACT
The effect of d-amphetamine on selective attention in humans was investigated by measuring event-related potentials (ERPs) during a complex auditory selective attention task (CSAT). The CSAT required subjects to make a button press response to infrequent target tones presented amongst tones that varied in pitch (high vs. low), location (left vs. right ear) and duration (51 ms vs. 102 ms). Healthy subjects completed the CSAT under three conditions: placebo, 10 mg and 20 mg d-amphetamine, at least one week apart. D-amphetamine produced a significant dose response increase in hit-rate and decrease in reaction time without changing false alarm rate. D-amphetamine reduced late PN to location irrelevant stimuli and pitch irrelevant stimuli in both the attended and unattended location. The effect of d-amphetamine was interpreted as a decrease in the maintenance of the attentional trace to irrelevant stimuli. However, these changes were accompanied by some evidence of processing of stimulus features in the unattended location. These results suggest that d-amphetamine improves selective attention, and decreases the maintenance of attention to irrelevant stimuli.
Subject(s)
Affect/drug effects , Attention/drug effects , Central Nervous System Stimulants/pharmacology , Dextroamphetamine/pharmacology , Evoked Potentials, Auditory/drug effects , Evoked Potentials/drug effects , Administration, Oral , Adult , Blood Pressure/drug effects , Central Nervous System Stimulants/administration & dosage , Dextroamphetamine/administration & dosage , Dose-Response Relationship, Drug , Double-Blind Method , Female , Heart Rate/drug effects , Humans , Male , Schizophrenia/physiopathologyABSTRACT
BACKGROUND: The aim of the present study was to further investigate a previously reported attention-related impairment in dependent amphetamine users using event-related potential (ERP) indices of selective attention. METHODS: ERPs were recorded during an auditory selective attention task (SAT) that involved detecting infrequent long-duration target tones presented among short-duration tones that varied in location (left vs. right ear) and pitch (low vs. high). Amphetamine users (n = 19) were divided into two groups, high dependence (n = 10) and low dependence (n = 10), based on amphetamine Severity of Dependence Scale scores, and compared to an age-matched control group (n = 9). RESULTS: The high-dependence group showed slowed reaction time and reduced early processing negativity and peak N1 amplitude to location-relevant nontarget stimuli. Poor performance on the SAT was highly correlated with deficits in early processing, which were also related to poor performance on the Wechsler Memory Scale Attention/Concentration index. CONCLUSIONS: It is suggested that severely dependent users suffer an inability to selectively enhance the sensory processing of relevant auditory information. This may produce poor automatic preferential processing of relevant information and increase load on limited attentional resources.
Subject(s)
Amphetamine-Related Disorders/physiopathology , Attention/physiology , Cerebral Cortex/physiopathology , Cognition Disorders , Evoked Potentials/physiology , Volition/physiology , Adolescent , Adult , Amphetamine-Related Disorders/complications , Amphetamines/adverse effects , Analysis of Variance , Attention/drug effects , Auditory Perception/physiology , Case-Control Studies , Central Nervous System Stimulants/adverse effects , Cognition Disorders/chemically induced , Cognition Disorders/physiopathology , Cues , Discrimination, Psychological/physiology , Evoked Potentials/drug effects , Female , Humans , Linear Models , Male , Neural Inhibition/drug effects , Neural Inhibition/physiology , Sensitivity and Specificity , Severity of Illness Index , Stress, Psychological/physiopathology , Volition/drug effectsABSTRACT
The purpose of this study was to clarify the extent of neuropsychological impairment previously found among amphetamine users (McKetin and Mattick, 1997) by comparing them with a non-drug-using control group. Amphetamine users who were classified as low dependence (n = 15) or high dependence (n = 11) according to the severity of dependence scale (SDS) were compared to non-drug-using control subjects (n = 9) on indices of the Wechsler Memory Scale-Revised (WMS-R). Dependent amphetamine users (high dependence group) performed approximately one half of a standard deviation worse than controls on the verbal memory, attention/concentration and delayed recall indices of the WMS-R but amphetamine users who were less dependent (low dependence group) showed no impairment.
Subject(s)
Amphetamine-Related Disorders/complications , Attention/drug effects , Cognition Disorders/chemically induced , Memory Disorders/chemically induced , Memory/drug effects , Adult , Case-Control Studies , Chi-Square Distribution , Confidence Intervals , Female , Humans , Male , Multivariate Analysis , Neuropsychological Tests , Severity of Illness Index , Wechsler ScalesABSTRACT
The purpose of this study was to assess cognitive functioning in a group of illicit amphetamine users. A neuropsychological test battery (Wechsler Memory Scale-Revised (WMS-R) and the digit symbol, block design and vocabulary subtests of the Wechsler Adult Intelligence Scale-Revised (WAIS-R) and the National Adult Reading Test (NART)) was administered to 78 amphetamine users (mean age = 22.5 years; 46 males, 33 females). Severity of amphetamine dependence was found to be associated with poorer performance on both memory and attention/concentration indices of the WMS-R. The relative contribution of amphetamine dependence, concurrent drug use and other drug related factors to neuropsychological functioning are discussed.
