Eosinophilic pleural effusion associated with the addition of sodium valproate

Optimizing co-prescription of clozapine and antiseizure medications: a systematic review and expert recommendations for clinical practice

INTRODUCTION

Antiseizure medication (ASM) add-on to clozapine may be efficient to target clozapine-resistant mood or psychotic symptoms or clozapine-related adverse drug reactions (ADR) such as seizures. We aimed to synthesize the information relevant for clinical practice on the risks and benefits of clozapine-ASM co-prescription.

AREAS COVERED

Articles were identified with MEDLINE, Web of Sciences and PsycINFO search from inception through October 2023. The review was restricted to ASM with mood-stabilizing properties or with potential efficacy for resistant psychotic symptoms (valproate (VPA), lamotrigine, topiramate, carbamazepine, oxcarbazepine).

EXPERT OPINION

VPA add-on to clozapine is associated with a high risk of serious ADR (myocarditis, neutropenia, pneumonia) mostly explained by complex time-dependent drug-drug interactions. The initial inhibitory effects on clozapine metabolism require slow titration to avoid immuno-allergic reactions. After the titration period, VPA has mainly inductive effects on clozapine metabolism that are more marked in smokers requiring therapeutic drug monitoring. Lamotrigine and topiramate add-on may be recommended as the first-line treatment for clozapine-related seizures, but there is limited evidence regarding the efficacy of this strategy for clozapine-resistant psychotic symptoms. Carbamazepine should not be co-prescribed with clozapine because of its potential for agranulocytosis and for inducing clozapine metabolism.

Clinical and pathophysiological characteristics of valproate-induced pleural effusion

INTRODUCTION

Valproic acid is a carboxylic acid derivative commonly prescribed for several types of seizure disorders or for acute manic episodes in patients with bipolar disorder. Several cases of valproate-induced pleural effusion have been reported, although the precise pathophysiological mechanism remains unknown.

OBJECTIVE

To describe the presentation of pleural effusion associated with valproate use and to categorize published case reports according to clinical, immunological, and pleural effusion cell type.

METHODS

PubMed/MEDLINE and Embase databases were systematically searched from January 1970 until November 2020 using the following search terms: "valproic acid" OR "valproate" OR "pleural fluid" OR "exudative effusion" OR "transudative effusion" OR "valproic lung adverse events". These searches yielded 171 references of which 135 articles were considered irrelevant, leaving 36 potentially relevant references which were carefully scrutinized. Twenty-eight cases of valproate-induced pleural effusion were identified after excluding two articles reporting five patients with lung parenchymal adverse reactions to treatment with valproic acid; two articles reporting three patients in whom the pleural effusion could not be attributed to valproic acid alone; one case discussing valproate therapy and fungal pleural effusion; and one describing a patient who suffered from severe cardiac failure. There were also two cases, in an abstract form, with pericardial and pleural effusion, but without any further informative details, and, thus, they were also excluded from this survey.

EXUDATIVE EOSINOPHILIC PLEURAL EFFUSION

This was the most common type of valproate-induced pleural effusion reported in 17 out of 28 cases (60.7%), with concurrent peripheral eosinophilia in ten. Acute hypersensitivity reaction, inflammation of the pleural cavity induced by the drug, drug toxicity, and damage to mesothelial cells due to oxidants, comprise the possible pivotal mechanisms.

EXUDATIVE LYMPHOCYTIC PLEURAL EFFUSION

This was reported in two cases, with concurrent pericardial effusion in one. Discontinuation of valproate led to resolution of the effusion, although the underlying pathophysiological mechanisms remain abstruse. Interestingly, a patient presented with recurrent pleural effusion characterized by transition from eosinophilic to lymphocytic predominance after readministration of valproate.

TRANSUDATIVE PLEURAL EFFUSION

Three out of 28 cases (10.7%) were characterized by neutrophilic transudative pleural effusion after long-term therapy with valproate, while concurrent pericardial effusion was also noted in two.

VALPROATE-INDUCED LUPUS ERYTHEMATOSUS WITH PLEURAL EFFUSION

Five patients receiving valproate therapy (17.9% out of the 28 cases) developed drug-induced lupus erythematosus with concurrent pleural effusion that was eosinophilic in three. All patients had positive antinuclear antibodies; anti-histone antibodies were positive in two.

CONCLUSIONS

Valproate-induced pleural effusion is rare, but patients receiving treatment with valproic acid who develop respiratory symptoms should be examined for valproate-induced pleural effusion.

Clozapine-related Sudden Pericarditis in a Patient Taking Long Acting Aripiprazole and Valproate: A Case Report

Clozapine may be associated with cardiovascular adverse effects including QTc prolongation and, more rarely, with myocarditis and pericarditis. Although rare, these latter cardiovascular adverse effects may be life-threatening and must be immediately recognized and treated. Several cases of clozapine related-pericarditis have been described and often it has a subtle and insidious onset with symptoms that may be often misdiagnosed with psychiatric manifestations (e.g. anxiety, panic or somatization) leading to a delayed correct diagnosis with potential fatal consequences. In the present report we describe the case of a 27-year-old girl with schizoaffective disorder taking long acting aripiprazole and valproate who developed a sudden onset clozapine-related pericarditis during titration phase that resolved with immediate clozapine discontinuation and indomethacin administration. We underline the importance of an early diagnosis of clozapine-related pericarditis and the need to have monitoring protocols to prevent this potentially fatal adverse effect especially when polypharmacy is administered to patients taking clozapine.

Three patients needing high doses of valproic Acid to get therapeutic concentrations

Valproic acid (VPA) can autoinduce its own metabolism. Cases requiring VPA doses >4000 mg/day to obtain therapeutic plasma concentrations, such as these 3 cases, have never been published. Case 1 received VPA for seizures and schizophrenia and had >50 VPA concentrations in 4 years. A high dose of 5,250 mg/day of VPA concentrate was prescribed for years but this dose led to an intoxication when switched to the enterocoated divalproex sodium formulation, requiring a normal dose of 2000 mg/day. VPA metabolic capacity was significantly higher (t = −9.6; df = 6.3, p < 0.001) during the VPA concentrate therapy, possibly due to autoinduction in that formulation. Case 2 had VPA for schizoaffective psychosis with 10 VPA concentrations during an 8-week admission. To maintain a VPA level ≥50 μg/mL, VPA doses increased from 1500 to 4000 mg/day. Case 3 had tuberous sclerosis and epilepsy and was followed up for >4 years with 137 VPA concentrations. To maintain VPA concentrations ≥50 μg/mL, VPA doses increased from 3,375 to 10,500 mg/day. In Cases 2 and 3, the duration of admission and the VPA dose were strongly correlated (r around 0.90; p < 0.001) with almost no change after controlling for VPA concentrations, indicating progressive autoinduction that increased with time.

Valproic acid-induced eosinophilic pleural effusion: a case report and review of the literature

We present a case of eosinophilic pleural effusion due to valproic acid (VPA), a rare adverse event that has been reported previously. A 30-year-old male patient presented with respiratory symptoms and right-sided pleuritic pain, within days of initiation of VPA treatment for a generalized seizure. Chest radiography revealed a moderate-sized right-sided pleural effusion, which was an exudate with a pH of 7.54 and 48% eosinophils. Symptoms resolved soon after discontinuation of the drug, as did the effusion in a repeat radiograph 3 weeks later. The likelihood that VPA was the cause of the effusion is examined.