Has thrombocytopenia previously been described for omeprazole?/nA 33-year-old man with a history of

Fråga: Has thrombocytopenia previously been described for omeprazole? A 33-year-old man with a history of bile duct cancer develops thrombocytopenia (now 26x 10E9) 2-5 days after starting Losec (omeprazole; 20 mg x1) and Primperan (metoclopramide; 10 mg x1). Baseline thrombocytes were 139 x10E9. Concomitant medications: Morphine injections, 1.0 ml 3-4 x1 sc, as required.

Sammanfattning: In an extensive literature search, we did not find any reports of thrombocytopenia caused by omeprazole with the exception of 3 cases reported in SWEDIS and one case report. A causal-relationship cannot be ruled out in this case.

Svar: In a literature search we found no reports on omeprazole and thrombocytopenia. In Meyler´s Side Effects of Drugs we found a case describing a 47-year-old man who developed thrombocytopenia after intake of omeprazole. The patient had a history of chronic alcoholism and ulcerating esophagitis. He developed progressive thrombocytopenia 4 days after starting to take omeprazole (20 mg/day). Other causes were excluded and the reaction resolved after discontinuation of omeprazole (1).

In FASS (2), thrombocytopenia is listed as a rare (< 1/1000) adverse drug reaction of omeprazole. In SWEDIS (3), there are four cases of thrombocytopenia associated to omeprazole therapy. Concomitant drugs included acetylsalicylic acid, furosemide, digoxin, fluoxetine and levomepromazine. The WHO adverse drug reaction monitoring centre in Uppsala has received reports of a total of 308 cases of thrombocytopenia associated with omeprazole. However, these reports cannot be properly evaluated.

No documentation on thrombocytopenia and metoclopramide was located.

Regarding morphine, we found a single report describing a 33-year-old woman who developed sudden thrombocytopenia after administration of morphine. A morphine dependent platelet antibody was found in the patient´s serum (4). In an extensive literature search including Medline, Drugline, SWEDIS and standard pharmacological textbooks, we found no similar reports. In FASS, thrombocytopenia is not listed as an adverse drug reaction of morphine (2).

We recommend this case be reported to SADRAC (The Swedish Adverse Drug Reactions Advisory Committee).