Pharmacokinetics of mycophenolate mofetil in Omani patients on cyclosporine or tacrolimus

BACKGROUND

Mycophenolate mofetil (MMF) reduces rejection in organ transplantation and is effective in controlling autoimmune diseases. Determining the area under the receiver operating characteristic curve (AUC) of MMF is not routine despite interindividual variability. The aim of this study was to look into MMF-AUC in Omani patients on cyclosporine (CsA) or tacrolimus (Tac).

METHODS

We measured MMF-AUC in 27 stable Omani patients. We used the 4-time-points-limited sampling strategy.

RESULTS

Sixteen, 8, and 3 recipients were receiving Tac, CsA, and calcineurin inhibitor (CNI)-free regimens, respectively. The mean MMF dose was 1,685 ± 442 mg/d. All except 3 patients were within or above the target AUC. The AUC was significantly higher in patients receiving Tac versus CsA. All patients on Tac were within or above the target AUC. Seven of the 8 patients with MMF-AUC above target were receiving Tac. Two of the 3 patients with MMF-AUC below target were on CsA.

DISCUSSION

These preliminary results confirm the significant interindividual variability of MMF-AUC. None of the recipients on Tac had an AUC below target. Most patients above the target AUC were receiving Tac. Two of the 3 patients with MMF-AUC below target were on CsA and receiving 1 g/d MMF. Patients on Tac are at risk of having higher than the target AUC, exposing them to overimmunosuppression. Recipients on CsA seem to require >1 g/d MMF.

CONCLUSIONS

These preliminary results encourage measuring the AUC of MMF. The fixed MMF dose regimen seems to be unreliable to predict the AUC. Preventing under- or overimmunosuppression offsets the burden.

Management of BK virus nephropathy in kidney transplant recipients at the Royal Hospital - Clinical Audit - Oman

OBJECTIVES

Nephropathy from BK virus (BKV) infection is a growing challenge in kidney transplant recipients globally. It is the result of contemporary potent immunosuppressives aimed at reducing acute rejection and improving allograft survival. Untreated BK virus infections lead to kidney allograft dysfunction or loss. Decreased immunosuppression is the principle treatment but predisposes to acute and chronic rejection. Screening for early detection and prevention of symptomatic BK virus nephropathy may improve outcomes. Although no approved antiviral drug is available, leflunomide, cidofovir, quinolones, and intravenous immunoglobulin have been used. Since the introduction of the new immunosuppressive agents in the transplant regimen at the Royal Hospital, Few cases of BK virus have been detected, and the challenge was to decide upon the best treatment option.

MATERIALS AND METHODS

The audit was carried out at the Royal Hospital-Oman between January 2010 and December 2012. The nephrology consultant and the clinical pharmacist reviewed all the BK cases and the Royal Hospital. Extensive literature review carried out by the pharmacist to look into the prevalence, prognosis and treatment of BK nephropathy. A treatment protocol was prepared by the clinical pharmacist through guidance of the consultant and was peer reviewed by team of clinical pharmacists and nephrology doctors and approved by the consultant.

RESULTS

The audit included 19 patients with positive BK virus ployoma nephropathy. The treatment options were applied stepwise in all the patients with BK virus nephropathy with success rate more than 70%.

CONCLUSIONS

BK virus nephropathy is emerging at an alarming rate and requires increasing awareness. The uses of current treatment options are still questionable. Our audit confirms that reducing immunosuppression appears to be the criterian standard for the treatment of BK nephropathy.

A Study of Prescribing Valsartan in Out-patient Clinics at the Royal Hospital, Muscat, Oman

OBJECTIVES

Angiotensin Receptor Blockers such as Valsartan, are a newer class of drugs associated with significant reductions in cardiovascular morbidity and mortality. They are commonly used in hypertension, chronic heart failure, diabetes-related nephropathy and post-myocardial infarction in patients who are intolerant to Angiotensin Converting Enzyme inhibitors (ACEi). A review of medicines used in Royal Hospital (an Omani tertiary health care centre) during 2004 and 2005 showed that Valsartan was one of 20 most expensive drugs used. The main objective of this study was to evaluate the pattern of prescribing valsartan in out-patient clinics.

METHODS

a retrospective study, applying medicines use evaluation, to describe the pattern of prescribing Valsartan in comparison with international guidelines. The study carried out in the outpatient pharmacy setting, Royal Hospital from 15th May to 30th June 2006. It included 120 adult patients who had been prescribed Valsartan at the outpatient clinics during the study period.

RESULTS

among the 120 patients only 109 patients were finally included in the study. Elevenpatients who had had duplicated prescriptionswere excluded from the study. 78% of the patients were on Valsartan for its FDA-approved indications while 22% of patients were for other non-approved indications. Half of the patients were initiated on an ACEi before shifting to Valsartan. The other half of the patients was started with Valsartan as a first line choice without any clinical justification.

CONCLUSION

The study showed that half of the patients were initiated on Valsartan without being prescribed an ACEi prior to that, while the recommendation in most of the international guidelines based on indication stated that ARBs are used in patients who are intolerant to ACEi. The study emphasizes the need for further research to highlight the need for developing national guidelines and adhering to these guidelines for rational prescribing.

Prophylaxis for opportunistic infections for kidney transplantation recipients at the royal hospital in oman

OBJECTIVES

The main objective of this study is to ensure all patients undergone kidney transplantation receives appropriate standard PCP prophylaxis soon after transplantation, unless contraindicated.

METHODS

A prospective study included all kidney transplantation recipients from January 2008 to August 2008. A data collection sheet was designed and reviewed in focus group meetings and modified accordingly. The subjects were followed-up during the admission for transplantation to the date of discharge. The discharge prescriptions were screened to ensure all the kidney transplantation recipients were prescribed appropriate PCP prophylaxis before discharge. All prescriptions with NO PCP prophylaxis were intervened by the clinical pharmacist. The focus group meetings suggested designing a questionnaire using likerts scale. The purpose was to highlight doctors' perception towards PCP prophylaxis for renal transplant recipients. The questionnaires were distributed to all the nephrology doctors (consultants, senior specialists and medical officers). The data were entered in the data collection sheet and were analyzed by using simple statistical methods.

RESULTS

Almost 80% of the prescriptions did not included (TMP/SMX) for PCP among which 20% of the prescriptions were for patients with G6PD deficiency. The clinical pharmacist's interventions resulted that all discharge prescriptions were modified and (TMP/SMX) was prescribed for patients who were legible for a PCP prophylaxis

CONCLUSION

In the absence of prophylaxis, the incidence of PCP in solid organ transplant recipients ranges from 6.8% to 22%, necessitating PCP prophylaxis for at least 6 months following transplantation. Despite the widespread knowledge on PCP prophylaxis, most of the patients were discharged with no prophylactic treatment for PCP. After pharmacist's intervention the prescriptions were edited and PCP prophylaxis was added.