Neuroleptic malignant syndrome with the addition of aripiprazole to clozapine

Atypical neuroleptic malignant syndrome in patients treated with aripiprazole and clozapine: a case-series study and short review

OBJECTIVES

Neuroleptic malignant syndrome (NMS) requires emergency treatment and can be fatal. Combined aripiprazole and clozapine therapy is rarely used in clinical settings, and NMS related this combination still lacks evaluation. Herein, we present two cases of atypical NMS treated with aripiprazole and clozapine.

METHODS

Case 1 was a schizophrenic male with a history of NMS under treatment with aripiprazole 20 mg. He was hospitalized and maintained with aripiprazole 5 mg and clozapine 225 mg. On the 25th day, atypical NMS occurred with rigidity, elevated creatine kinase, and stupor, which subsided with supportive therapy. He was discharged under treatment with aripiprazole 15 mg and fluoxetine 60 mg. Case 2 was a female with schizoaffective disorder without a history of NMS. She was hospitalized and maintained with clozapine 50 mg and aripirazole 30 mg. On the 11th day, atypical NMS occurred with mild fever, delirium, and rigidity, which subsided under supportive therapy.

RESULTS AND CONCLUSIONS

Our cases highlight the atypical features of NMS in patients being treated with combined ari-piprazole and clozapine. Consciousness change, modest elevation of creatine kinase, and leukocytosis were the most consistent findings; hyperthermia accounts for only some of the cases. This is a reminder of the importance of earlier detection of the soft signs and atypical features of NMS under this combined treatment.

Fever development in neuroleptic malignant syndrome during treatment with olanzapine and clozapine

Neuroleptic malignant syndrome (NMS) is the most dangerous life-threatening complication of antipsychotic medication. It's development is connected with the blockade of dopaminergic transmission (D2 receptors) in the nigrostriatal system of the brain. Fever is one of the main symptoms of this syndrome and it's elevation is due to the activation of the immune system. Numerous studies report that treatment with clozapine (doses 37.5-600 mg) or olanzapine (doses 10-25 mg) or the use of these drugs in polytherapy cause pyrexia between 37.8-40.6 °C. Additionally, levels of proinflammatory interleukins such as IL-6, IL-1,TNF-α were increased. The aim of this article is to describe how olanzapine and clozapine influence fever development in NMS, in relation to the dose of the drug taken by schizophrenic patients including changes in immunological system.

Urgent and emergent psychiatric disorders

In the emergency department, neurologists regularly evaluate patients exhibiting behavioral abnormalities that stem from underlying neurologic diseases. This behavior may be the initial presence of a neurologic illness or may indicate the deterioration and progress of the disease process. In addition, many neurologic patients present with acute and potentially dangerous psychiatric symptoms that demand rapid and accurate management. Assessment, diagnosis, and treatment of patients with psychiatric manifestations in the context of neurologic illness pose a significant challenge to treating neurologists. This article discusses a general approach to assessment and treatment of some of the more common psychiatric disorders.

Increased aripiprazole concentrations in an HIV-positive male concurrently taking duloxetine, darunavir, and ritonavir

OBJECTIVE

To report a case of increased aripiprazole concentrations during coadministration with darunavir, ritonavir, and duloxetine.

CASE SUMMARY

A 43-year-old HIV-positive Hispanic man received darunavir/ritonavir-based antiretroviral therapy (ART) in addition to aripiprazole and duloxetine for depression and anxiety. A month after the aripiprazole dosage was increased to 50 mg daily, the patient developed confusion and loss of coordination. Weeks later, he presented to the emergency department with fever, cough, headache, neck stiffness, back pain, and blurred vision and was admitted for possible meningitis. Because symptoms improved with pain control and intravenous fluids during hospitalization, he was discharged within a couple days after admission. One month later he was readmitted for worsening symptoms, and the resulting diagnostic workup showed unremarkable findings except for lymphadenopathy (LAD). This finding was attributed to discontinuing ARTs after his first admission. He was discharged on aripiprazole 50 mg daily, darunavir 800 mg daily, ritonavir 100 mg daily, and duloxetine 60 mg daily. A random steady-state concentration of aripiprazole was 1100 ng/mL (therapeutic concentration 100-200 ng/mL) obtained 49 days after discharge.

DISCUSSION

The Horn Drug Interaction Probability Scale demonstrated a possible relationship between the increased aripiprazole concentration and coadministration of darunavir/ritonavir and duloxetine, which inhibit CYP3A4 and 2D6. Potential confounders to the increased concentration include duloxetine inhibition of CYP2D6 polymorphism, possible 2D6 polymorphism, and exceeding aripiprazole's maximum dose. The initial presentation of confusion and loss of coordination may have been early signs of aripiprazole toxicity, which relapsed as shown by his symptoms prior to admission.

CONCLUSIONS

The interaction between aripiprazole and darunavir, ritonavir, and duloxetine may be significant. Clinicians should be cognizant of increased risk of aripiprazole toxicity in HIV-positive patients concurrently taking ritonavir-boosted ART and other cytochrome P450 inhibitors like duloxetine. Dose adjustments or monitoring parameters should be an area of research and discussion.