Treatment of refractory hypotension with low-dose vasopressin in a patient receiving clozapine

Vasopressin as adjunctive therapy in pulmonary hypertension associated with refractory systemic hypotension in term newborns

OBJECTIVE

The use of vasopressin as an adjunctive therapy in pulmonary hypertension associated with refractory systemic hypotension has increased. The objective of our study is to describe its effects on term infants.

STUDY DESIGN

Retrospective observational study. Setting in a referral level IV neonatal intensive care unit from a middle-income region. The patients are term neonates admitted to our NICU who required vasopressin due to severe Pulmonary Hypertension and refractory hypotension during a 49-month period (December 2019 and December 2023).

RESULTS

We identified 68 term infants, all in mechanical ventilation, receiving inhaled nitric oxide (iNO), and a phased protocol management for hypotension. Vasopressin was a started at a mean of 2 days with a mean duration of 80 h. Regarding hemodynamic outcome: diastolic, systolic, and median systemic pressure significantly increased during the first 4 h of treatment, as well as arterial pH and urine output. Accordingly, lactate and Vasoactive Inotropic Score (VIS) score decreased after 4 and 8 h, respectively, after vasopressin was started. Regarding oxygenation markers: oxygen requirements and mean airway pressure decreased significantly (and therefore the oxygenation index decreased in concordance) after 4 h of vasopressin. Echocardiographic indices of pulmonary hypertension progressively improved after vasopressin infusion with a significant decrease of tricuspid ingurgitation velocities and the rate of right-to- left ductal shunt through the ductus arteriosus. In the same way, left and right ventricular output increased after the initiation of vasopressin.

CONCLUSION

This study showed that the use of vasopressin in neonates with persistent pulmonary hypertension was associated with a rapid and significant improvement in oxygenation and hemodynamic markers of perfusion, including blood pressure. Its effects begin early during the first hours of treatment.

Treatment strategies for clozapine-induced hypotension: a systematic review

BACKGROUND

Clozapine is the most effective medication for treatment-refractory schizophrenia but is associated with significant adverse drug effects, including hypotension and dizziness, which have a negative impact on quality of life and treatment compliance. Available evidence for the management of clozapine-induced hypotension is scant.

OBJECTIVES

Due to limited guidance on the safety and efficacy of pharmacological treatments for clozapine-induced hypotension, we set out to systematically review and assess the evidence for the management of clozapine-induced hypotension and provide guidance to clinicians, patients, and carers.

DESIGN

We undertook a systematic review of the safety and efficacy of interventions for clozapine-induced hypotension given the limited available evidence.

DATA SOURCES AND METHODS

PubMed, Embase, PsycINFO, CINAHL, and the Cochrane trial Registry were searched from inception to November 2021 for literature on the treatment strategies for clozapine-induced hypotension and dizziness using a PROSPERO pre-registered search strategy. For orthostatic hypotension, we developed a management framework to assist in the choice of intervention.

RESULTS

We identified nine case studies and four case series describing interventions in 15 patients. Hypotension interventions included temporary clozapine dose reduction, non-pharmacological treatments, and pharmacological treatments. Midodrine, fludrocortisone, moclobemide and Bovril^® combination, and etilefrine were associated with improvement in symptoms or reduction in orthostatic hypotension. Angiotensin II, arginine vasopressin, and noradrenaline successfully restored and maintained mean arterial pressure in critical care situations. A paradoxical reaction of severe hypotension was reported with adrenaline use.

CONCLUSION

Orthostatic hypotension is a common side effect during clozapine titration. Following an assessment of the titration schedule, salt and fluid intake, and review of hypertensive and nonselective α1-adrenergic agents, first-line treatment should be a temporary reduction in clozapine dose or non-pharmacological interventions. If orthostatic hypotension persists, fludrocortisone should be trialled with monitoring of potassium levels and sodium and fluid intake. Midodrine may be considered second-line or where fludrocortisone is contraindicated or poorly tolerated. For patients on clozapine with hypotension in critical care settings, the use of adrenaline to maintain mean arterial pressure should be avoided.

REGISTRATION

PROSPERO (Registration No. CRD42020191530).

Paradoxical refractory hypotension following adrenaline administration in a patient taking clozapine

Clozapine is a potent antipsychotic commonly used for refractory schizophrenia. Adverse effects are well recognised including constipation, intestinal obstruction, agranulocytosis and cardiomyopathy. We present a case of paradoxical refractory hypotension following epinephrine administration in a patient taking clozapine. A psychiatric inpatient who had been taking clozapine for many years developed paralytic ileus and obstruction requiring surgical intervention. Following initiation of epinephrine administration intraoperatively he developed refractory hypotension which improved only when epinephrine was weaned off. This effect is likely due to uninterrupted β2-agonist activity in the presence of clozapine-induced α-blockade. Clinicians need to have greater awareness of this serious interaction and avoid the use of epinephrine in patients taking clozapine.

Vasopressor-Refractory Shock From Clozapine Overdose Treated With Synthetic Angiotensin II Infusion

Background:

Clozapine is an atypical antipsychotic with potent alpha-adrenergic blocking properties when administered at high dosages, resulting in vasodilatory shock in overdose settings.

Case Summary:

A 39-year-old man presented with profound catecholamine- and vasopressin-refractory vasodilatory shock following massive clozapine ingestion. Angiotensin II was initiated when the patient was requiring 2.2 µg/kg/min norepinephrine equivalents of vasopressor support, resulting in a prompt increase in the perfusion pressure. All vasopressors were liberated within 18 hours of angiotensin II initiation, and the patient was discharged with no deficits.

Conclusions:

Synthetic angiotensin II may represent a therapeutic option for refractory hypotension resulting from high dosages of clozapine or other potent alpha-adrenergic blocking medications.

Clozapine-Induced Cardiovascular Side Effects and Autonomic Dysfunction: A Systematic Review

Background: Clozapine is the antipsychotic of choice for treatment-resistant schizophrenia and has minimal risk for extrapyramidal symptoms. Therapeutic benefits, however, are accompanied by a myriad of cardiometabolic side-effects. The specific reasons for clozapine's high propensity to cause adverse cardiometabolic events remain unknown, but it is believed that autonomic dysfunction may play a role in many of these.

Objective: This systematic review summarizes the literature on autonomic dysfunction and related cardiovascular side effects associated with clozapine treatment.

Method: A search of the EMBASE, MEDLINE, and EBM Cochrane databases was conducted using the search terms antipsychotic agents, antipsychotic drug^*, antipsychotic^*, schizophrenia, schizophren^*, psychos^*, psychotic^*, mental ill^*, mental disorder^*, neuroleptic^*, cardiovascular^*, cardiovascular diseases, clozapine^*, clozaril^*, autonomic^*, sympathetic^*, catecholamine^*, norepinephrine, noradrenaline, epinephrine, adrenaline.

Results: The search yielded 37 studies that were reviewed, of which only 16 studies have used interventions to manage cardiovascular side effects. Side effects reported in the studies include myocarditis, orthostatic hypotension and tachycardia. These were attributed to sympathetic hyperactivity, decreased vagal contribution, blockade of cholinergic and adrenergic receptors, reduced heart rate variability and elevated catecholamines with clozapine use. Autonomic neuropathy was identified by monitoring blood pressure and heart rate changes in response to stimuli and by spectral analysis of heart rate variability. Metoprolol, lorazepam, atenolol, propranolol, amlodipine, vasopressin and norepinephrine infusion were used to treat tachycardia and fluctuations in blood pressure, yet results were limited to case reports.

Conclusion: The results indicate there is a lack of clinical studies investigating autonomic dysfunction and a limited use of interventions to manage cardiovascular side effects associated with clozapine. As there is often no alternative treatment for refractory schizophrenia, the current review highlights the need for better designed studies, use of autonomic tests for prevention of cardiovascular disease and development of novel interventions for clozapine-induced side effects.

Failure of Induced Hypertension for Symptomatic Vasospasm in the Setting of Clozapine Therapy

BACKGROUND

Hemodynamic augmentation is utilized as a treatment in the setting of symptomatic cerebral vasospasm. This approach includes the use of vasopressors to induce hypertension with the aim of improved cerebral blood flow. Agents with potent alpha-1 antagonism properties, including clozapine, can inhibit or blunt the response of several vasopressor agents.

METHODS

Case report.

RESULTS

A 54-year-old schizophrenic male with an aneurysmal subarachnoid hemorrhage required hemodynamic augmentation in which several vasopressor trials resulted in no or poor response. The addition of epinephrine resulted in a decrease of mean arterial pressure. Vasopressin initiation demonstrated an immediate vasopressor effect.

CONCLUSIONS

Vasopressors are an important treatment modality in symptomatic cerebral vasospasm. This case highlights the potential for clozapine to blunt the effects of vasopressors; or in the case of epinephrine, it causes a reversal effect. Vasopressin may be considered an agent of choice in patients who have recently taken clozapine and require hemodynamic augmentation.

Paliperidone Palmitate Associated with Necrotizing Deep Tissue Infection and Sepsis Requiring Surgical Intervention

Long-acting injectable antipsychotics provide the delivery of medication over an extended period of time requiring administration typically only every 2 to 4 weeks. The side effect profile of a long-acting injectable antipsychotic is predictable and similar to the oral formulation. However, injection site reactions may occur with this novel delivery system. The risk of an injection site reaction may be greater with the repeated administration of a lipophilic decanoate formulation and include pain, development of indurations, and fibrosis. Severe complications from injection site reactions have rarely been described in the literature with newer agents. We report the first case of a patient prescribed paliperidone palmitate every 3 weeks that developed severe sepsis requiring vasopressors and intubation due to delayed relayed recognition of a necrotizing infection at an injection site. Clinicians should be alerted to screen for injection site reactions when there is an unknown source infection in a patient receiving a long-acting injectable antipsychotic.

Vasopressin as a rescue therapy for refractory pulmonary hypertension in neonates: case series

OBJECTIVES

To determine the effect of vasopressin therapy on the efficacy of oxygenation and arterial pressure in infants with severe persistent pulmonary hypertension of the newborn.

DESIGN

Retrospective case study.

SETTING

Neonatal ICU, Hospital for Sick Children, Toronto, Canada.

SUBJECTS

Neonates with severe persistent pulmonary hypertension.

INTERVENTION

Intravenous infusion of vasopressin.

MEASUREMENTS AND MAIN RESULTS

Ten infants satisfied the inclusion criteria. Inhaled nitric oxide was used for median (interquartile range) duration of 15 hours (11-28 hr) prior to vasopressin commencement. Vasopressin was initiated at a mean dose of 0.0002 ± 0.0002 U/kg/min for a median (interquartile range) duration of 49 hours (13-95 hr). Administration of vasopressin was associated with an improvement in oxygenation index, peak effect 6 hours after drug initiation (p = 0.01), and a reduction in inhaled nitric oxide dose (p < 0.05). There was a concomitant improvement in blood pressure (p < 0.05) and urine output (p < 0.05), without drop in the serum sodium level or worsening in serum lactate level.

CONCLUSIONS

Although there is limited experience of vasopressin use in persistent pulmonary hypertension of the newborn infants, our case series suggests it to be a potential adjunctive therapy for improving the efficacy of oxygenation and systemic hypotension. A prospective randomized trial is needed to confirm its efficacy and safety in the management of severe persistent pulmonary hypertension of the newborn.