Evaluating the conversion to extended-release tacrolimus from immediate-release tacrolimus in liver transplant recipients

Tacrolimus-Induced Neurotoxicity After Transplant: A Literature Review

Tacrolimus, a calcineurin inhibitor, is an immunosuppressant used globally to prevent rejection after organ transplantation. Although it significantly improves outcomes for solid organ transplant patients, it is associated with various side effects such as nephrotoxicity and neurotoxicity. Tacrolimus-induced neurotoxicity is frequently encountered in clinical practice and can present with a variety of symptoms that may occur even at therapeutic levels. Although tacrolimus-induced neurotoxicity is well documented, there is limited literature available on pharmacologic management. Twenty-eight case reports of tacrolimus-induced neurotoxicity were identified and analyzed in addition to other literature including reviews, retrospective studies, and animal model studies. The severity of cases of tacrolimus-induced neurotoxicity reported ranged from mild symptoms that could be managed with symptomatic treatment to conditions such as posterior reversible encephalopathy syndrome and chronic inflammatory demyelinating polyradiculoneuropathy that may require more immediate intervention. This information was utilized in addition to clinical experience to compile potential management options for prevention and treatment of neurotoxic adverse events. This review is limited by the utilization of primarily retrospective studies and case reports. The available literature on the subject is largely narrative and there are no guidelines on treatment of tacrolimus-induced neurotoxicity at the time of this research. This comprehensive review may guide further studies to investigate the pathophysiology of tacrolimus-induced neurotoxicity and to define patient-specific strategies for mitigation or minimization of neurotoxicity. This is especially important given that management of tacrolimus-induced neurotoxicity can include changes to immunosuppression that can result in an increased risk of rejection.

A report of a prospective randomized trial of extended-release tacrolimus versus immediate release tacrolimus after liver transplantation with anti-thymocyte induction in a steroid free protocol

PURPOSE

Our study hypothesis was that once daily dosing of extended-release tacrolimus (XRT) would be a safe and effective immunosuppression (IS) with the potential to decrease adverse events (AEs) associated with immediate release tacrolimus (IRT) after liver transplantation (LT).

METHODS

All patients receiving LT at our center received rabbit anti-thymocyte globulin (RATG) induction therapy. Eligible patients were randomized in a 1:1 fashion to receive either XRT or IRT. Antimicrobial prophylaxis was the same between arms, and both groups received an antimetabolite for the first 6 months following LT. Patients were then followed at pre-determined study intervals for the following year after LT. We administered the RAND-36SF survey to assess patient's health-related quality of life at pre-determined intervals. All analysis was performed with an intention to treat basis.

RESULTS

We screened 194 consecutive patients and enrolled 110. Our control and study arms were well matched. Transplant characteristics were similar between groups. At all timepoints, both arms had similar serum creatinine and estimated glomerular filtration rate (eGFR), calculated by MDRD6 equation, with post-transplant GFRs between 60 and 70 mL/min/1.73 m2 . Tacrolimus trough levels were similar between arms. The XRT arm had fewer AEs (166) and fewer serious AEs (70) compared to IRT (201 and 99, respectively). AEs most commonly were renal, infectious, or gastrointestinal in nature. While not statistically significant, XRT was held temporarily (25 vs. 35 cases) or discontinued (3 vs. 11 cases) less frequently than IRT and had fewer instances of rejection (7 vs. 12 cases).

CONCLUSION

This analysis showed that XRT is safe and effective as de novo maintenance IS in a steroid-free protocol with RATG.

Tremor Induced by Cyclosporine, Tacrolimus, Sirolimus, or Everolimus: A Review of the Literature

Calcineurin inhibitors such as cyclosporine and tacrolimus are immunosuppressant drugs that are known to induce tremors. Non-calcineurin inhibitors such as sirolimus and everolimus have also reportedly been accompanied by tremors, albeit less likely. However, the prevalence rates reported in the literature are notably wide, and the risk profiles for these drug-induced tremors are less understood. We searched PubMed to extract data on the risk of tremors with these drugs when prescribed for various transplant and non-transplant indications. We ascertained whether the risk of drug-induced tremor is influenced by the underlying diagnosis, dosing formulations, drug concentrations, and blood monitoring. We extracted data on treatment strategies and outcomes for tremors. Articles were primarily screened based on English language publications, abstracts, and studies with n ≥ 5, which included case series, retrospective studies, case-controlled studies, and prospective studies. We found 81 eligible studies comprising 33 cyclosporine, 43 tacrolimus, 6 sirolimus, and 1 everolimus that discussed tremor as an adverse event. In the pooled analysis of studies with n > 100, the incidence of tremor was 17% with cyclosporine, 21.5% with tacrolimus, and 7.8% with sirolimus and everolimus together. Regarding the underlying diagnosis, tremor was more frequently reported in kidney transplant (cyclosporine 28%, tacrolimus 30.1%) and bone marrow transplant (cyclosporine 40%, tacrolimus 41.9%) patients compared with liver transplant (cyclosporine 9%, tacrolimus 11.5%) and nontransplant indications (cyclosporine 21.5%, tacrolimus 11.3%). Most studies did not report whether the risk of tremors correlated with drug concentrations in the blood. The prevalence of tremors when using the twice-daily formulation of tacrolimus was nearly the same as the once-daily formulation (17% vs 18%). Data on individual-level risk factors for tremors were lacking. Except for three studies that found some benefit to maintaining magnesium levels, there were minimal data on treatments and outcomes. A large body of data supports a substantive and wide prevalence of tremor resulting from tacrolimus use followed by cyclosporine, especially in patients receiving a kidney transplant. However, there is little reporting on the patient-related risk factors for tremor, risk relationship with drug concentrations, treatment strategies, and outcomes.

Magnetic Resonance Guided Focused Ultrasound Thalamotomy for Treatment of Severe Essential Tremor in a Lung Transplant Recipient-A Case Report

Calcineurin inhibitor-related tremors occur in up to 50% of solid organ transplant recipients and are disabling in severe cases. We describe a bilateral lung transplant recipient with essential tremors that significantly worsened after tacrolimus initiation. She did not have improvement with the change to extended-release tacrolimus, the use of everolimus as a calcineurin inhibitor-sparing agent, or the addition of primidone, clonazepam, or propranolol. She underwent magnetic resonance-guided focused ultrasound thalamotomy with significant improvement in her tremor and activities of daily living.

Immunosuppression in Uterus Transplantation: Experience From the Dallas Uterus Transplant Study

BACKGROUND

Uterus transplantation is a temporary transplant allowing women with absolute uterine factor infertility to experience pregnancy and childbirth. The degree of immunosuppression (IS) required to prevent rejection while minimizing toxicity to the recipient and fetus remains an area of investigation.

METHODS

In this article, we describe immunosuppressive therapy, rejection episodes, infections, and adverse events in 14 uterus transplant recipients. Induction consisted of antithymocyte globulin and methylprednisolone. Ten recipients (71%) received no steroids postoperatively, and 4 (29%) had steroids tapered off at 42 d. All received oral tacrolimus, either immediate release (n = 2, 14%) or extended release (n = 12, 86%). Mycophenolate was used in 4 cases (29%), de novo azathioprine in 9 (64%), and de novo everolimus in 1 (7%).

RESULTS

Sixteen clinically silent, treatment-responsive rejection episodes occurred in 10 recipients. Five recipients (36%) experienced acute kidney injury. In 3 recipients, IS was discontinued due to renal dysfunction. Eleven infection episodes were noted in 7 recipients. No babies had congenital abnormalities.

CONCLUSIONS

Our experience demonstrates that safe IS regimens can be used for uterus transplant recipients before and during pregnancy.

Phenomenology and Physiology of Tacrolimus Induced Tremor

Background

Tacrolimus is a potent immunosuppressant drug commonly used after solid organ transplant surgery. The use of this drug is frequently associated with the emergence of tremors. There is little information on the clinical and physiological characteristics of tacrolimus-induced tremors. Characterizing these tremors is essential as they can promote the development of specific therapies.

Methods

We describe four patients placed on tacrolimus immunosuppressant therapy following kidney transplant surgery and who developed tremors impacting their daily functional activities. We describe the clinical and physiological characteristics of the tremor and the response generated after a limb cooling test.

Results

A postural and kinetic tremor mainly involving the distal hands was observed in our cohort. In the accelerometer-based assessment, the tremor amplitude was noted to be mild to moderate, and the frequency was 5-6 Hz. Cooling the forearm and the hand led to a temporary albeit significant reduction of tremor amplitude (p = 0.03). Limb cooling lowered the tremor frequency by 1 Hz in two patients with no change in the other two patients, and the statistical comparison was not significant (p > 0.05).

Conclusions

Limb cooling may be pursued as a therapeutic option for addressing tacrolimus-induced tremor, as the patients in our cohort benefitted from temporary tremor suppression.