Co-prescribing of SSRIs and TCAs in Australia: how often does it occur and who is doing it?

AIMS

To determine the frequency with which the selective serotonin re-uptake inhibitor (SSRI) antidepressants are used as add-on therapy to the tricyclic antidepressants (TCA) rather than as replacement therapy.

METHODS

The data analysed were profiles of prescription records by date of supply to the patient. From within the national administrative dispensing claims database, the subset eligible for social security entitlements was identified as individuals by means of their coded permanent identification numbers (PINs). Following the initial supply of an SSRI in January 1996, the subsequent 6 months dispensing of SSRI and TCA antidepressants to these individuals was examined. The main outcome measure was the proportion of individuals to whom SSRIs and TCAs were dispensed concurrently, as an indirect measure of coprescription. In instances where a patient was receiving prescriptions for SSRIs and TCAs that had been written by the one doctor only, the major specialty of the doctor was investigated.

RESULTS

55 271 PINs were dispensed 63 865 SSRI prescriptions in January 1996 which represented over half (52%) of the total community SSRI prescriptions dispensed in that month. The number of these patients meeting the criteria for coprescription of SSRIs and TCAs over the next 6 months was 2773 (5%). The coprescribing instances were highest in Queensland and the prescribers most frequently involved had psychiatry major specialty codes.

CONCLUSIONS

Among SSRI users there is a cohort of patients who, within the same time frame, are receiving supplies of a TCA, the nonselective drug that the SSRIs were designed to replace. This is indirect evidence of probable coprescription. Such combination use is of uncertain clinical and cost effectiveness, and carries additional risks. The SSRIs were included on the subsidy list in Australia on the basis of reasonable cost effectiveness as monotherapy compared with the TCAs. Our data imply that for some patients, antidepressant prescribing is inconsistent with the basis on which government subsidy was approved.

Acute direct adenoviral vector cytotoxicity and chronic, but not acute, inflammatory responses correlate with decreased vector-mediated transgene expression in the brain

The potential utility of adenoviruses for the treatment of chronic neurological disease is controversial due to reports of vector-associated toxicity, inflammation, and transient transgene expression. To focus upon the mechanism by which transgene expression is lost, we injected increasing doses [1 x 10(6) to 1 x 10(9) infectious units (iu)] of a first-generation adenovirus vector expressing beta-galactosidase into the brains of immune-competent adult rats. Transgene expression was evaluated simultaneously with acute neuronal and glial cell cytotoxicity, and acute and chronic inflammation using immunohistochemistry, at 3 and 30 days post-vector administration. Our results show a clear threshold effect of viral dose upon the amount of transgene expression persisting by 30 days after vector administration. Below 10(8) iu, transgene expression remained stable over the 30-day period. Following infection of more than 10(8) iu, the extent of transgene expression at 30 days was inversely correlated with increasing viral dose. The severity of acute inflammation increased proportionally with increasing vector dose from 10(6) to 10(9) infectious units. In contrast, acute vector-mediated cytotoxicity and chronic inflammation were observed only above the threshold level of vector dose. Above 10(8) iu both the extent of the acute toxicity and the severity of the chronic inflammation were inversely correlated with transgene expression at 30 days. Thus, our data suggest that both an acute loss of cells through direct vector-mediated toxicity and the elicitation of chronic inflammation (but not acute inflammation) may account for the decline in transduction persistence at high vector doses.

Examining the adequacy of quantities available for subsidized antidepressant prescriptions in Australia

In Australia the Pharmaceutical Benefits Scheme (PBS), a national drug insurance plan, aims to provide around a month's therapy for medication used in chronic conditions. However, there are marked differences among the most commonly used antidepressants in the number of days supply represented by the PBS maximum quantity after adjustment for the defined daily dose (DDD). The DDD is the assumed adult daily dose for a drug and is a WHO drug utilization standard. Whereas the selective serotonin re-uptake inhibitors (SSRIs) and moclobemide largely provide around a month's supply at the DDD, most tricyclic antidepressant (TCA) items provide considerably less than this .A patient tracking study was conducted to determine the average length of time between prescription re-supplies for a number of tricyclic antidepressants and newer antidepressants as a means of measuring the efficiency of PBS supply for the different classes of antidepressant. The number of days between dispensings was similar for patients no matter whether they were taking TCAs, SSRIs or moclobemide, although for the older antidepressants presumably at a much lower prescribed daily dose than the DDD. Care needs to be taken when adjusting usage with the DDD/1000/day unit of measurement in cases where the DDD does not reflect the prescribed daily dose (PDD).

Sarcoidosis of the pancreas: a case report

Sarcoidosis involving the pancreas is quite rare, having been reported only 10 times in the English language literature. Its clinical presentation is often similar to pancreatic cancer, with common presenting symptoms including abdominal pain, weight loss, jaundice, and anorexia. Diagnosis has been made in all cases at laparotomy, and in the majority of cases, no previous history of sarcoidosis was reported. Treatment has ranged from observation to pancreaticoduodenectomy for suspected malignancy. Prognosis is favorable with no significant morbidity or mortality reported postoperatively. The case we report is that of a patient with a prior history of sarcoidosis who presented with a clinical picture suggestive of pancreatic malignancy. However, the patient was found to have sarcoidosis involving the pancreas, with no evidence of malignancy at laparotomy.

Gastrointestinal complications following cardiac surgery

This study sought to determine which factors influence the mortality rate in patients developing gastrointestinal complications following cardiac surgery. Between July 1988 and January 1992, 2054 patients underwent cardiac surgical procedures at the Boston University Medical Center. Of these, 29 (1.4%) developed postoperative gastrointestinal complications. The overall mortality rate among these patients was 27% (8/29). Those who died following such complications had a higher incidence of New York Heart Association (NYHA) class IV and unstable symptoms (8/8, 100% versus 3/21, 14%; P < 0.0001), and an increased need for preoperative intra-aortic balloon pump support (4/8, 50% versus 1/21, 5%; P < 0.004). The need for gastrointestinal surgical intervention increased the mortality rate significantly compared with patients managed medically (8/18, 44% versus 0/11, 0%; P < 0.01). Patients with ischemic bowel also had a significantly higher mortality (5/5, 100% versus 3/24, 12%; P < 0.001). It is concluded that most patients with gastrointestinal complications following cardiac surgery can be treated, and with acceptable mortality rates. The presence of unstable symptoms, preoperative intra-aortic balloon pump support, ischemic bowel and the need for gastrointestinal surgical intervention adversely affect mortality.

Iatrogenic arterioportal fistulae: diagnosis and management

Arterioportal fistulae can develop from a variety of causes, either congenital, iatrogenic, or acquired. They can have a varied clinical presentation including acute upper gastrointestinal bleeding, ischemic colitis, abdominal pain, ascites, and abdominal bruit. In the past the treatment has been ligation and surgical excision of the fistula with repair of the artery and vein or hepatic lobectomy. We report two patients with arterioportal fistulae between the hepatic artery and portal vein as a result of liver biopsy and transhepatic portography. Both patients were treated successfully by nonoperative radiologic intervention.

Effect of severe anoxia on the permeability of gastric mucosa (38517)

The effect of severe anoxia produced by gassing with 100% nitrogen on gastric mucosal permeability and hydrogen ion back diffusion was investigated using an in vitro preparation of rabbit fundic gastric mucosa mounted in an Ussing chamber. Permeability was estimated by determination of the flux of the water soluble, nonlipidsoluble molecule erythritol from the mucosal to serosal solution. The flux rate across normal tissue was 2.80 plus or minus 0.41 pmoles/cm-2/sec, and rose to 3.32 plus or minus 0.57 pmoles/cm-2/sec after 2 hr of severe anoxia. Hydrogen ion ack diffusion was measured by determining with a pH stat the amount of hydrogen required to maintain the [H+] of the mucosal solution at 0.1, 1.0, 2.0 and 3.2 mEq/L in both normal and anoxic tissues. One hour of anoxia increased the back diffusion of H+, but the changes only became statistically significant at all pH values after 1.5 hr. Anoxia did however cause an immediate fall in potential difference to zero, and a rise in resistance which after 30 min fell progressively to preanoxic levels. Anoxia produces a small increase in gastric mucosal, permeability, an effect which may be enhanced by other factors.

Small intestinal mucosal abnormalities in relatives of patients with dermatitis herpetiformis

Jejunal biopsy has been carried out in 19 relatives of patients with dermatitis herpetiformis and stereomicroscopic abnormalities have been found in seven. The majority of the relatives in whom these abnormalities were found had no bowel symptoms: one had the rash of dermatitis herpetiformis. All but one of the propositi of the relatives in whom were found small intestinal mucosal abnormalities themselves had the coeliac syndrome. It is concluded that a genetic factor is involved in the production of the enteropathy of dermatitis herpetiformis as in other forms of the coeliac syndrome.