Overdose of aripiprazole, a new type of antipsychotic

Identification of the key target profiles underlying the drugs of narrow therapeutic index for treating cancer and cardiovascular disease

An appropriate therapeutic index is crucial for drug discovery and development since narrow therapeutic index (NTI) drugs with slight dosage variation may induce severe adverse drug reactions or potential treatment failure. To date, the shared characteristics underlying the targets of NTI drugs have been explored by several studies, which have been applied to identify potential drug targets. However, the association between the drug therapeutic index and the related disease has not been dissected, which is important for revealing the NTI drug mechanism and optimizing drug design. Therefore, in this study, two classes of disease (cancers and cardiovascular disorders) with the largest number of NTI drugs were selected, and the target property of the corresponding NTI drugs was analyzed. By calculating the biological system profiles and human protein–protein interaction (PPI) network properties of drug targets and adopting an AI-based algorithm, differentiated features between two diseases were discovered to reveal the distinct underlying mechanisms of NTI drugs in different diseases. Consequently, ten shared features and four unique features were identified for both diseases to distinguish NTI from NNTI drug targets. These computational discoveries, as well as the newly found features, suggest that in the clinical study of avoiding narrow therapeutic index in those diseases, the ability of target to be a hub and the efficiency of target signaling in the human PPI network should be considered, and it could thus provide novel guidance in the drug discovery and clinical research process and help to estimate the drug safety of cancer and cardiovascular disease.

Prolonged QRS Widening After Aripiprazole Overdose

BACKGROUND

Aripiprazole is an atypical antipsychotic with a long half-life. Overdose can result in protracted somnolence and cardiac disturbances, particularly QT interval prolongation.

METHODS

This is a single case report of a 14-year-old boy who took an overdose of aripiprazole and developed QRS widening.

CASE

A 14-year-old boy intentionally ingested 20 tablets of aripiprazole (5 mg). He was brought to the emergency department when his ingestion was discovered. The patient's vital signs were as follows: temperature, 37.7°C; heart rate, 108 beats/min; blood pressure, 138/98 mm Hg; and respirations, 16 breaths/min. Activated charcoal was administered within 90 minutes of ingestion. Initial electrocardiogram (EKG) showed sinus tachycardia, with a QRS of 138 ms and QT interval of 444 ms. QRS duration was 90 ms on an EKG performed 3 months earlier. A bolus of sodium bicarbonate was administered, and the patient was transferred to the pediatric intensive care unit. Repeat EKG demonstrated a QRS of 156 ms, and a sodium bicarbonate infusion was initiated. The patient continued to have QRS prolongation for the next 8 days, reaching a peak of 172 ms 3 days postingestion. Despite aggressive treatment with sodium bicarbonate, there was persistent QRS prolongation; however, the patient did not have any dysrhythmias and remained hemodynamically stable. The patient was discharged 9 days postingestion when the QRS duration normalized to 82 ms. Genetic testing revealed that the patient was a CYP2D6 poor metabolizer.

CONCLUSIONS

This case suggests that aripiprazole toxicity may possibly be associated with QRS prolongation without associated dysrhythmias or cardiovascular compromise. In addition, toxicity may be prolonged in patients who are CYP2D6 poor metabolizers.

Overdoses with Aripiprazole: Signs, Symptoms and Outcome in 239 Exposures Reported to the Danish Poison Information Centre

The aim of this study was to characterize the clinical signs and symptoms of exposures to aripiprazole overdoses. We retrospectively identified all aripiprazole exposures reported to the Danish Poison Information Centre (DPIC) from June 2007 to May 2015. Information concerning demographics, ingested dose and symptoms was extracted from the DPIC database and medical records. Information on death and admission to hospital was obtained from Danish national registers. We analysed 239 cases, 86 concerning single-drug exposures to aripiprazole, and 153 cases where aripiprazole had been taken with at least one other substance (mixed-drug). The median ingested aripiprazole dose was 105 mg (IQR: 50-1680 mg) in the single-drug exposure group and 120 mg (IQR: 60-225 mg) in the mixed-drug exposure group. The most commonly reported symptom was light sedation, reported in 63% of the single-drug group and 50% of the mixed-drug exposure group. There were no malignant arrhythmias or ECG abnormalities after single-drug exposures. No deaths were recorded in relation to the intake. We found a long-term mortality rate of 13 deaths per 1000 person-years (95% CI: 7; 23 per 1000 person-years), which is significantly higher than in an age- and gender-matched background population. In conclusion, we found that aripiprazole overdoses had few and mild symptoms predominantly related to the sedative properties. We detected a benign cardiovascular safety profile and no new safety concerns. Our findings may support an increased threshold of 300 mg for hospital admission after a single-drug exposure with aripiprazole and symptoms not worse than light sedation.

Toxicologic Emergencies in Patients with Mental Illness: When Medications Are No Longer Your Friends

Patients with psychiatric disorders are at risk for toxicologic emergencies. Psychotropic medications have numerous effects on the neurologic, cardiac, and other organ systems and interact with other medications, potentially leading to further side effects. It is important to become familiar with accepted psychiatric practice guidelines, common toxidromes, medical sequelae associated with prescribed medications, and the specific workup and treatment of overdoses of frequently prescribed psychotropics.

Atypical permanent neurological sequelae after an acute intoxication with lithium and aripiprazole

OBJECTIVES

The aim of the present case report was to describe atypical neurological sequelae after a lithium and aripiprazole co-intoxication in a suicide attempt.

METHODS

We report the case of a 31-year-old patient with bipolar disorder who developed, after lithium and aripiprazole massive ingestion, a severe pseudobulbar dysarthria and motor disorders suggestive of basal ganglia micro lesions. We review literature on neurological sequelae due to acute lithium intoxications.

RESULTS

Acute lithium intoxication can cause permanent neurological sequelae, the most frequent clinical feature being a permanent cerebellar syndrome. Moreover, the widely-prescribed combination of lithium with antipsychotics increases the neurotoxicity in lithium intoxications. In this case, both atypical neurological syndrome and normal paraclinical investigations lead first to misdiagnose the lithium neurological damages.

CONCLUSIONS

This case illustrates that acute lithium intoxications can result in serious and potentially permanent neurological deficits, which remain difficult to diagnose. Imaging abnormalities are not constant, and neurological presentation can be atypical.

The cardiac safety of aripiprazole treatment in patients at high risk for torsade: a systematic review with a meta-analytic approach

RATIONALE

Certain antipsychotics increase the risk of heart rate-corrected QT (QTc) prolongation and consequently Torsades de Pointes (TdP) and sudden cardiac death (SCD). Drug-induced Brugada syndrome (BrS) is also associated with SCD. Most SCDs occur in patients with additional cardiac risk factors.

OBJECTIVES

Aripiprazole's cardiac safety has not been assessed in patients at high risk for torsade, where QTc prolongation risk is highly increased.

METHODS

MEDLINE, Embase, and The Cochrane Library were searched for preclinical, clinical, and epidemiological studies. Eligible studies were reviewed and cardiac safety data were extracted. Continuous and dichotomous QTc data were used in the meta-analysis.

RESULTS

Preclinical studies suggested that aripiprazole has limited affinity for the delayed rectifier potassium current. TdP was reported in two case reports and SCD was reported in one case report and one case series. No clinical studies assessing aripiprazole's cardiac safety in patients at high risk for torsade were found. No thorough QT (TQT) study with aripiprazole was found. The meta-analysis revealed that the mean ΔQTc interval was decreased with aripiprazole and QTc prolongation risk was lower compared with placebo and active controls. Epidemiological studies linked aripiprazole to weak/moderate torsadogenicity. No studies were found associating aripiprazole with BrS suggesting low affinity for the fast sodium current.

CONCLUSIONS

Aripiprazole is a low-risk antipsychotic regarding cardiac safety in healthy patients. However, baseline and steady state electrocardiogram is recommended in patients at high risk for torsade due to marked QTc prolongation, absence of a TQT study, and lack of data in this group.

Torsades De Pointes after Administration of Low-Dose Aripiprazole

OBJECTIVE:

To describe a case of torsades de pointes (TdP) in a patient treated with aripiprazole.

CASE SUMMARY:

A 42-year-old white male with schizophrenia, diabetes, hypertension, and a history of stroke was admitted to the intensive care unit following 2 days of fever, diarrhea, and altered mental status. Following the resolution of his acute illness, previous therapy with quetiapine 400 mg orally at bedtime was resumed for schizophrenia and presumed delirium. Quetiapine was discontinued after 1 dose because of QTc interval prolongation. Twenty-three days later, with a baseline Q Tc interval of 414 milliseconds, aripiprazole 2.5 mg orally once daily was initiated. Following 5 days of aripiprazole therapy, the patient had a cardiac arrest due to TdP. Normal sinus rhythm was restored after 30 seconds of cardiopulmonary resuscitation, 1 shock of 200 Joules, and 4 g of intravenous magnesium sulfate. Serial electrocardiographs obtained after aripiprazole discontinuation revealed resolution of QTc interval prolongation.

DISCUSSION:

Aripiprazole is a second-generation antipsychotic that may be selected for patients with prolonged QTc intervals and at risk for TdP. Data from trials indicate that aripiprazole has minimal effects on the QTc interval. However, in this case, aripiprazole was associated with TdP in a patient with minimal risk factors. The Naranjo probability scale was used to determine a probable association between aripiprazole and the development of TdP. To our knowledge, this is the first reported case of TdP associated with the use of aripiprazole.

CONCLUSIONS:

Five days of low-dose aripiprazole therapy was associated with the development of TdP in a man with minimal risk factors. Clinicians should be aware of this potential adverse drug event with aripiprazole.

Toxicology and overdose of atypical antipsychotics

BACKGROUND

Second-generation antipsychotic medications, or "atypical antipsychotics," are now first-line therapy in the treatment of schizophrenia and other psychotic disorders, and are additionally being used in a wide array of other psychiatric and non-psychiatric conditions in both adults and children. Overdose is frequently reported to poison control centers.

OBJECTIVES

We review the toxicology and general management of poisonings involving the atypical antipsychotic medications.

DISCUSSION

The most serious toxicity involves the cardiovascular system and the central nervous system. All typical and atypical antipsychotics cause sedation, which is pronounced in overdose. The most common cardiovascular effects that occur after atypical antipsychotic overdose are tachycardia, mild hypotension, and prolongation of the QTc interval. Other clinical syndromes in overdose include neuroleptic malignant syndrome (NMS) and antimuscarinic delirium. Seizures may be observed. No antidotes exist for these poisonings, but they most often do well with supportive care.

CONCLUSION

Antipsychotic overdose produces a gamut of manifestations that affect multiple organ systems. Treatment is primarily supportive. Specific therapies for NMS, hypotension, and seizures are discussed.

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.

Risk assessment of isolated aripiprazole exposures and toxicities: a retrospective study

STUDY OBJECTIVE

To characterize the clinical effects of acute isolated aripiprazole poisonings and to assess the toxic dose of this drug.

METHODS

All isolated acute aripiprazole exposures reported to a poison control system from January 2002 through September 2006 were retrospectively reviewed. Patients with incomplete information or those lost to follow-up were excluded.

RESULTS

A total of 286 cases were identified. Mean age was 18.9 years (SD 15.7), with a range of 6 months-70 years. Seventy-seven patients (27%) were <or=6 years, 80 patients (28%) were 7-17 years, and 129 patients (45%) were >or=18 years. Doses were known in 255 patients (89%). Symptoms occurred in 158 patients (55%): somnolence 89 (56%), tachycardia 32 (20%, heart rate 102-186), nausea/vomiting 29 (18%), dystonic reactions 21 (13%), tremor 9 (6%), agitation 3 (2%), dizziness 3 (2%), paresthesia 2 (1%), headache 2 (1%), dysphagia 1 (<1%), syncope 1 (<1%), minor facial swelling 1 (<1%), and hypotension 1 (<1%). None of the patients required intubation, and there were no deaths or EKG abnormalities. Median dose for symptomatic and asymptomatic groups were 25 and 15 mg, respectively, for <or=6 years (p = 0.02); 60 and 30 mg for 7-17 years (p = 0.01); and 100 and 75 mg for >or=18 (p = 0.25). In comparison of drug groups (Group 1, <or=20 mg; Group 2, 21-90 mg; Group 3, >or=91 mg), symptoms were more likely to occur in Group 2 versus Group 1 (OR 2.29, 95% CI 0.79-6.61) in patients <or=6 years; in Group 3 versus Group 1 (OR 3.39, 95% CI 1.07-10.73) followed by Group 2 versus Group 1 (OR 1.14, 95% CI 0.36-3.56) in patients 7-17 years; and in Group 3 versus Group 1 (OR 1.36, 95% CI 0.54-3.42) but not any more likely in Group 2 versus Group 1 (OR 0.92, 95% CI 0.33-2.52) in patients >or=18 years.

CONCLUSIONS

Acute aripiprazole poisonings most commonly result in sedation, sinus tachycardia, nausea/vomiting, or dystonic reactions. Symptoms are more likely with doses above 90 mg, although pediatric patients can be affected at a lower dose.

A systematic review of cardiovascular effects after atypical antipsychotic medication overdose

As the use of atypical antipsychotic medications (AAPMs) increases, the number of overdoses continues to grow. Cardiovascular toxicity was common with older psychiatric medications but seems uncommon with AAPM. We conducted a systematic literature review to describe the cardiovascular effects reported after overdose of 5 common AAPM: aripiprazole, olanzapine, quetiapine, risperidone, and ziprasidone. We included case reports and case series describing overdose of these 5 medications identified in a search of MEDLINE, EMBASE, and abstracts from major toxicology meetings. We found 13 pediatric cases (age, <7 years), 22 adolescent cases (age, 7-16 years), and 185 adult cases. No pediatric case described a ventricular dysrhythmia or a cardiovascular death. In the adolescent and adult cases, we found numerous reports of prolonged corrected QT interval and hypotension, but there were only 3 cases of ventricular dysrhythmia and 3 deaths that may have been due to direct cardiovascular toxicity. The results from case series reports were similar to the single case report data. Our review suggests that overdose of AAPM is unlikely to cause significant cardiovascular toxicity.

Detection and quantification of aripiprazole and its metabolite, dehydroaripiprazole, by gas chromatography–mass spectrometry in blood samples of psychiatric patients

Aripiprazole is a novel antipsychotic drug for the treatment of schizophrenia and schizoaffective disorders. In this study, a new method using gas chromatography-mass spectrometry (GC-MS) was developed and validated for the detection of aripiprazole and its main metabolite, dehydroaripiprazole, in plasma. Blood samples from seven psychiatric patients treated with aripiprazole (10-20 mg/day) underwent a solid-phase extraction (SPE) and N-methyl-N-trimethylsilytrifluoroacetamide (MSTFA) derivatization. The characteristic ions of mass spectra for aripiprazole and dehydroaripiprazole were m/z 306, 292, 218 and 304, 290, 218, respectively. Extraction recoveries from this method were 75.4% (n=5) for aripiprazole and 102.3% (n=5) for dehydroaripiprazole. The calibration curves of aripiprazole and dehydroaripiprazole were linear from 16 to 500 ng/ml (r(2)=0.999) and 8 to 250 ng/ml (r(2)=0.999), respectively. The respective limits of quantification (LOQs) for aripiprazole and dehydroaripiprazole evaluated in 0.5 ml of serum were 14.4 ng/ml and 6.9 ng/ml. Intra-assay and interassay precision and accuracy were within acceptable ranges. In this study, we also found that the mean trough concentrations in plasma at steady-state were 128.9 microg/l for aripiprazole and 30.1 microg/l for dehydroaripiprazole.

Efficacy with high-dose aripiprazole after olanzapine-related metabolic disturbances

OBJECTIVE

To report a case in which a patient tolerated and responded to high-dose aripiprazole and lost weight after having been on olanzapine for several years; a secondary objective is to discuss the use of aripiprazole dosages at higher than those recommended in the product's labeling.

CASE SUMMARY

A 57-year-old man with a 30 year history of schizophrenia had been taking olanzapine for 4 years, with the dosage titrated to 20 mg/day, to control the psychosis. After he had gained significant weight with olanzapine (the highest was 102.7 kg), his treatment was switched to aripiprazole. The patient required a high dose of aripiprazole (60 mg/day) to achieve full control of the psychiatric symptoms, and during aripiprazole therapy, he lost the weight he had gained while on olanzapine, weighing 85.9 kg within 7 months after the therapy switch.

DISCUSSION

Dosages of atypical antipsychotics higher than those recommended by the Food and Drug Administration are often used in clinical practice for refractory patients, despite the lack of evidence. The literature available on this subject is limited to small, double-blind trials; open-label trials; and case reports. Although certain patients may benefit from higher doses of atypical antipsychotics, the lack of evidence limits their use.

CONCLUSIONS

High-dose aripiprazole (60 mg/day) was well tolerated and controlled this patient's symptoms effectively. In addition, he lost weight that was gained while being treated with olanzapine. High-dose aripiprazole may be beneficial and safe in refractory patients; however, large, double-blind, randomized clinical trials are needed.