Movement disorders secondary to long-term treatment with cyclosporine A

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.

Insights into Pathophysiology from Medication-induced Tremor

Background

Medication-induced tremor (MIT) is common in clinical practice and there are many medications/drugs that can cause or exacerbate tremors. MIT typically occurs by enhancement of physiological tremor (EPT), but not all drugs cause tremor in this way. In this manuscript, we review how some common examples of MIT have informed us about the pathophysiology of tremor.

Methods

We performed a PubMed literature search for published articles dealing with MIT and attempted to identify articles that especially dealt with the medication's mechanism of inducing tremor.

Results

There is a paucity of literature that deals with the mechanisms of MIT, with most manuscripts only describing the frequency and clinical settings where MIT is observed. That being said, MIT emanates from multiple mechanisms depending on the drug and it often takes an individualized approach to manage MIT in a given patient.

Discussion

MIT has provided some insight into the mechanisms of tremors we see in clinical practice. The exact mechanism of MIT is unknown for most medications that cause tremor, but it is assumed that in most cases physiological tremor is influenced by these medications. Some medications (epinephrine) that cause EPT likely lead to tremor by peripheral mechanisms in the muscle (β-adrenergic agonists), but others may influence the central component (amitriptyline). Other drugs can cause tremor, presumably by blockade of dopamine receptors in the basal ganglia (dopamine-blocking agents), by secondary effects such as causing hyperthyroidism (amiodarone), or by other mechanisms. We will attempt to discuss what is known and unknown about the pathophysiology of the most common MITs.

Opsoclonus-myoclonus syndrome following long-term use of cyclosporine

BACKGROUND

Cyclosporine A (CsA) is a widely used immunosuppressive agent that may provoke unexpected neurologic complications. The mechanism is unclear and variable intervals have been reported between CsA administration and onset of the related side effects. Here, we describe a case of delayed-onset CsA neurotoxicity presenting as opsoclonus-myoclonus syndrome (OMS).

CASE DETAILS

A 37-year-old woman with a two-week period of opsoclonus and upper extremity myoclonus was admitted to our hospital. The patient had been taking CsA for 17 years after receiving a kidney transplant. Further evaluation did not reveal any other abnormalities. Seven days after switching from CsA to tacrolimus, in the absence of additional immune-modulating therapy, her neurologic symptoms improved considerably.

CONCLUSION

This is the case of delayed, long-term complications of CsA presenting as OMS. Symptoms resolved by substituting CsA with another immunomodulating drug. The etiology of the neurologic complications may involve paradoxically-enhanced delayed-type hypersensitivity.

[Nervous system side effects of disease modifying treatments of rheumatoid arthritis]

Antirheumatic medication is of crucial importance within the treatment concept of chronic inflammatory disorders. Side effects may affect various organ systems, among which are neurologic manifestations. If patients have comorbidities involving the nervous system this should be taken into consideration before choosing an individual immunosuppressant or immunomodulatory compound, as any worsening of the underlying neurologic disease should be avoided. In this article, relevant neurologic disorders will be described with respect to the clinical manifestations, differential diagnosis and treatment. In the second part, pharmaceuticals and biologicals which are frequently used as part of an antirheumatic regimen are discussed with respect to the potential to induce side effects specifically related to the nervous system.