Abstract
In this issue, two original research papers report comparisons of different formulations of the same drug. Lars Eriksson and colleagues examine the difference in use of quetiapine XR (long-acting) and quetiapine IR (short-acting) in a retrospective survey in Sweden. Overall XR quetiapine was used in higher doses than IR quetiapine with relatively more patients receiving doses greater than both 400mg and 600mg a day. Treatment discontinuation because of poor compliance was three times more common with IR than with XR. These observations point towards the XR preparation being better tolerated. Oddly, though, 98% of patients received other drugs besides quetiapine and over 80% concurrently received antipsychotics other than quetiapine. Polypharmacy is obviously de rigueur in Sweden. Meanwhile in Japan, Suzuki and co-workers report on their trial of switching patients on oral risperidone to the long-acting formulation of the drug. Depot antipsychotics are well known to provide better protection against relapse than oral drugs but are there other benefits? In this study, patients switched to long-acting risperidone did no better than those remaining on oral treatment in terms of symptom scores but they did end up on lower equivalent doses of risperidone, with lower prolactin levels, less severe movement disorder and on lower doses of co-prescribed benzodiazepines. In marked contrast to the Swedish study, all patients were treated with risperidone monotherapy.
Oral and injectable forms of psychotropics are, or course, by far the most widely used formulations in psychiatry. In other areas of medicine transdermal patches are relatively widely used. The advantages of the transdermal route include the provision of stable and sustained blood levels and the avoidance of the variability inherent in gastro-intestinal absorption and first pass metabolism. In their review article, Miriam Isaac and Carl Holvey examine the potential of transdermal delivery in psychiatry. In the UK we already have transdermal rivastigmine and nicotine but in other countries transdermal formulations of methylphenidate and selegiline are also used. Transdermal forms of fluoxetine and haloperidol are also in development. Isaac and Holvey report on the future of transdermal patches in psychiatry and include some intriguing case vignettes to demonstrate what can already be achieved today.
Another, almost inevitable, development in psychiatry is the medicinal use of cannabis constituents – either as experimental probes or as therapeutic agents. Zerrin Atakan is one of the world’s leading researchers into the psychotropic effects of cannabis constituents and her review article brings clarity to complex subject matter. The three best investigated constituents are delta-9-tetrahydrocannabinol (THC), cannabidiol (CBD) and delta-9-tetrahydrocannabivarin (THCV). THC is psychotogenic, anxiogenic and provokes disturbances of time perception. CBD (a similar compound from the same plant, remember) is, in bizarre contrast, anxiolytic and, it seems, antipsychotic. THCV is different still, being anticonvulsant and anorectic. These bare facts are in themselves fascinating but are put more engagingly into societal and medical context in Zerrin Atakan’s comprehensive review.
Two case reports with literature reviews complete this issue. In the first, Immadisetty and Agrawal describe the successful treatment of clozapine-associated parotid gland swelling with a combination of benzatropine and terazosin. In doing so they indirectly push the weight of evidence towards the cause of ‘hypersalivation’ towards actual hypersalivation and away from the “reduced passive swallowing” theory. The second case, from researchers at my own institute, describes a case of neonatal refractory hypoglycaemia in a baby born to a mother who had taken olanzapine during pregnancy. Both cases probably represent rare events but publication of their occurrence and treatment will, it is hoped, help clinicians facing similar situations as they are bound to occur in their practices around the world.