Severe neutropenia in a renal transplant patient suggesting an interaction between mycophenolate and fenofibrate.

OBJECTIVE: To describe a patient in whom initiation of micronized fenofibrate precipitated mycophenolate induced neutropenia. CASE SUMMARY: A 57-year-old man was admitted to the hospital because of febrile neutropenia. He had undergone kidney transplantation seventeen years ago. The patient's immunosuppressive maintenance regimen consisted of mycophenolate mofetil (MMF) 500 mg three times a day, and meprednisone 4 mg daily. His medical history included, hypertension treated with losartan 50mg daily, and dyslipidemia treated with ezetimibe 10mg /simvastatin 20mg for four years (until 2 weeks before admission when micronized fenofibrate 200 mg per day was started because of persistently elevated triglycerides levels. On presentation temperature was 37.8°C and initial laboratory tests showed 3130 White Blood Cell Count(WBC)/µL with neutropenia (absolute neutrophil count (ANC) 313/µL) Fenofibrate and mycophenolate mofetil were discontinued, piperacillin tazobactam 4.5gr three times a day and granulocyte stimulation factor 300 µg/day were started. Three days after admission WBC was 7280/µL, neutrophils: 22%, ANC: 1160/mm(3). Mycophenolate mofetil was restarted and granulocyte stimulation factor was discontinued. One month after discharge his WBC was 4480/µL and ANC 1926/µL. DISCUSSION: The initiation of fenofibrate in a patient on stable and therapeutic doses of mycophenolate may have precipitated mycophenolate induced neutropenia, a well described, dose dependent phenomenon. Mycophenolic acid (MPA) displays a complex pharmacokinetic profile susceptible to potential significant interactions with fenofibrate. Since approximately 99% of MPA and fenofibrate bind to albumin, displacement may occur, leading to increased free MPA. Second competition of fenofibric acid for UGT1A9 an enzyme implicated in conjugation of MPA may have decreased its metabolism. The combination of these two effects may increase the risk of dose dependent neutropenia. Using the Interaction Probability Scale (DIPS), the interaction was designated as probable. CONCLUSIONS: Until further evidence is available, when fenofibrate is started in a renal transplant patient on mycophenolate careful monitoring should be considered to avoid potentially fatal complications.

Pharmacovigilance and the cardiovascular system: two sides to every story.

PURPOSE: The objective of the present study was to quantify the reported cardiovascular adverse reactions and adverse reactions to cardiovascular drugs to help to design and implement monitoring and prevention strategies. METHODS: The pharmacovigilance unit (PU) is a peripheral effector of National Pharmacovigilance Center and receives adverse drug reactions notifications from 10 teaching hospitals. Data on adverse reactions beginning in 2004 and notified to the PU were extracted from the database. Cardiovascular adverse drug reactions and adverse reactions to cardiovascular drugs were identified using Medical Dictionary for Regulatory Activities (MedDRA), and the Anatomical Therapeutic Chemical (ATC) Classification System respectively. The reports of adverse reactions were classified according to their seriousness. RESULTS: From 2004 to 2010, 2516 notifications were received (2383 adverse reactions, 106 lack of efficacy, 26 quality failures). These notifications included 151 cardiovascular adverse reactions and 594 adverse reactions caused by cardiovascular drugs. In the first group, of the 151 cardiovascular adverse reactions through MedDRA SOC classification caused by all ATC group classes, 118 (78.2%) were caused by non cardiovascular drugs. Among them antimicrobials (27,2%) and neurologic drugs (21,2%) were the most frequent. 22 (14.6%) adverse reactions were serious. Long QT syndrome, peripheral edema, hypotension, tachycardia, and bradycardia, were the most frequent. In the second group, of the 594 reports identifying adverse reactions involving all MedDRA SOCs but caused only by cardiovascular drugs, 559 reports (94.1%) were non cardiovascular adverse reactions. Enalapril and furosemide accounted for 65.2% there were 33 (5.6%) serious adverse reactions. The most frequent adverse reactions were hyponatremia, impaired renal function, hypokalemia, metabolic alkalosis, asymptomatic elevation of liver enzymes, hyperkalemia, hyperglycemia, edema, and cough. CONCLUSION: Non-cardiovascular adverse reactions were the most frequent manifestation of adverse drug reactions caused by cardiovascular drugs and cardiovascular adverse reactions were most often caused by non cardiovascular drugs. This report highlights the importance of systematic evaluation of adverse drug reactions.

QT alterations in psychopharmacology: proven candidates and suspects.

Psychotropics are among the most common causes of drug induced acquired long QT syndrome. Blockage of Human ether-a-go-go-related gene (HERG) potassium channel by psychoactive drugs appears to be related to this adverse effect. Antipsychotics such as haloperidol, thioridazine, sertindole, pimozide, risperidone, ziprasidone, quetiapine, olanzapine and antidepressants such as amitriptyline, imipramine, doxepin, trazadone, fluoxetine depress the delayed rectifier potassium current (IKr) in a dose dependent manner in experimental models. The frequency of QTc prolongation (more than 456 ms) in psychiatric patients is estimated to be 8%. Age over 65 years, tricyclic antidepressants (TCA), thioridazine, droperidol, olanzapine, and higher antipsychotic doses were predictors of significant QTc prolongation. In large epidemiological controlled studies a dose dependent increased risk of sudden death has been identified in current users of antipsychotics (conventional and atypical) and of TCA. Thioridazine and haloperidol shared a similar relative risk of SCD. Lower doses of risperidone had a higher relative risk than haloperidol for cardiac arrest and ventricular arrhythmia. No increased risk was identified in current users of selective serotonin reuptake inhibitors (SSRI). Cases of TdP have been reported with thioridazine, haloperidol, ziprazidone, olanzapine and TCA. Evidence of QTc prolongation with sertindole is significant and this drug has not been approved by the Food and Drugs Administration (FDA). A large trial is ongoing to evaluate the cardiac risk profile of ziprazidone and olanzapine. Selective serotonin reuptake inhibitors have been associated with QTc prolongation but no cases of TdP have been reported with the use of these agents. There are no reported cases of lithium induced TdP. Risk factors for drug induced LQT syndrome and TdP include: female gender, concomitant cardiovascular disease, substance abuse, drug interactions, bradychardia, electrolyte disorders, anorexia nervosa, and congenital Long QT syndrome. Careful selection of the psychotropic and identification of patient's risk factors for QTc prolongation is applicable in current clinical practice.