(Es)omeprazole and tinnitus

Nederlands Bijwerkingen Centrum Lareb October 2013

Introduction

Omeprazole (Losec® ), a substituted benzimidazole, and esomeprazole (Nexium® ), the Senantiomer of omeprazole belong to the class of proton pump inhibitors (PPIs) which strongly reduce gastric acid secretion by the parietal cell [1]. PPIs are acid-activated prodrugs that require gastric acid secretion to be converted to the active sulfenic acids or sulfonamides [2]. The pharmacological mechanism of action is based on irreversible inhibition of the H+ /K+

-ATP-ase enzyme (the so-called proton pump) in the parietal cell of

the stomach mucosa. Both the basal and the stimulated gastric acid secretion are dose dependently inhibited [1-3].

Omeprazole has been registered since November 1988 and esomeprazole has been registered since August 2000. (Es)omeprazole is indicated for use in gastroduodenal ulcer disease, acid relate dyspepsia, reflux-oesophagitis or reflux symptoms and in ZollingerEllison’s syndrome [4]

The pharmacodynamic activity of omeprazole and esomeprazole is comparable. Other PPIs available on the Dutch market are lansoprazole, pantoprazole and rabeprazole [3]. Tinnitus is a sensation of hearing in the absence of external sounds. The cause of tinnitus is unknown in most cases. Tinnitus may occur together with changes in the cochlea, in the central nervous system, with intracranial hypertension, and other conditions. In some cases tinnitus can be psychosomatic. Tinnitus can also be an adverse drug reaction (ADR) of different types of drugs [5].

The current observation describes the association between (es)omeprazole and tinnitus.

Reports

On April 3rd 2013, the database of the Netherlands Pharmacovigilance Centre Lareb contained six reports of tinnitus or an aggravation of tinnitus associated with the use of omeprazole and four reports associated with the use of esomeprazole. The reports are listed in Table 1.

http://www.lareb.nl/Signalen/KWB_2013_3_(Es)omeprazole_and_tinnitus.aspx