[Clozapine-induced parotitis: a case study]

Clozapine is the drug of choice for patients with an unsatisfactory response to routine antipsychotic treatment. Side effects such as sedation, weight gain, hypotension and hypersialorrhea are frequently reported whereas clozapine-induced parotitis is a less known complication.

We report the case of a 32-year-old woman with a refractory schizoaffective disorder, bipolar type. The failure to respond to at least two well-conducted antipsychotic trials with flupentixol and risperidone, led clinicians to prescribe clozapine, which was started three years earlier. Since its introduction, clozapine induced sialorrhea, which has been managed until now with anticholinergic medication. Recently, Mrs B. was hospitalized for a new relapse. Once treatment compliance checked (good level of plasmatic dosage), we decided to increase the dose of clozapine from 350 mg/d to 500 mg/d. Twenty days later, Mrs B. exhibited improvement of symptoms but complained of acute bilateral auricular pain and odynophagia. The bilateral and comparative clinical exam displayed a bilateral filling of the retromandibular depression, the painful swelling of the parotid gland, along with ptyalism and a slight inflammatory oedema of the Stenon duct orifice. Mrs B. was apyretic, with physiological constants within the limits of normal values. The biological analyses displayed a discrete inflammatory syndrome (mild hyperleucocytosis and anemia), a negative mumps IgM test and positive mumps IgG test, and a 1050 ng/mL clozapine blood level. Once viral parotitis was ruled out, the involvement of clozapine was evoked. Symptomatic medication was prescribed with per os analgesic (paracetamol) and antiseptic mouthwash (Éludril). Clozapine dosage was lowered to 400 mg/d. A week later, clinical examination confirmed improvement of the medical and psychiatric conditions.

We report the case of a patient who developed a parotitis following clozapine dose adjustment. Clozapine induced parotitis was retained once the infectious and other organic etiologies had been ruled out. Previous cases of clozapine-induced parotitis have already been reported and we have some arguments to suspect this etiology in our case. First, Mrs B. experienced more hypersialorrhea with the increase in clozapine dosage. Second, the anticholinergic medication was interrupted 3 days before the episode of parotitis. Two main pathophysiological hypotheses, immune and inflammatory, have already been proposed to explain clozapine-induced parotitis. In the former, the immunomodulating properties of clozapine may sensitize the mononuclear blood cells, leading to the sialadenitis. The latter hypothesis is the more documented and proposes that clozapine-induced hypersialorrhea may be responsible for a chronic inflammatory state that can lead to the formation of a parotid lithiasis and consequently parotitis. This case report illustrates clozapine induced-parotitis, a poorly known complication of this compound. Clinicians should be aware of its hypersialorrhea and inflammatory consequences in order to better prevent the occurrence of this complication.