Case study: Cobicistat (Stribild▼) and fluticasone interaction

Background information

A man in his thirties was taking a combination treatment containing cobicistat (Stribild▼) for HIV therapy, prescribed by a genitourinary medicine (GUM) clinic. He also started taking a fluticasone inhaler, which was prescribed and dispensed at his GP surgery. Following this, the patient developed serious side effects. The Stribild product information included a warning that use of these medicines together is not recommended. GP suspected the man’s side effects were due to an interaction between the two drugs.  His GP completed a Yellow Card report highlighting this drug interaction and prescribing error. 

Investigation

The Medicines and Healthcare products Regulatory Agency (MHRA) experts led to a review of the product information for both cobicistat and fluticasone. The MHRA received three other reports (all received indirectly from pharmaceutical companies) of suspected interactions between these two drugs; all of which resulted in similar side effects with a total of eight cases in the EU. Although a possible interaction was already listed in the Stribild product information and use with fluticasone was not recommended, this warning did not specifically mention the severity of the side effects that may occur. In addition, the warning only included fluticasone and did not mention other corticosteroids, which are likely to have the same effect. There was also no warning of a possible interaction in the fluticasone product information or other corticosteroid product information. As shown by this Yellow Card report case, there is a possibility that the two drugs may not be prescribed or dispensed by the same person. The warning at the time was considered to be not enough. 

Response

Following review at a national and European level, it was agreed to make the warning clearer in the cobicistat product information leaflet and to add a warning to the product information for all non-topical corticosteroids about the possibility of an interaction and the types of side effects that may happen. In addition, a Drug Safety Update article was published to communicate this safety issue.

Additional information

Cobicistat is an antiretroviral medicine used for the treatment of HIV. Fluticasone is a synthetic corticosteroid that is used in the treatment of a variety of inflammatory and allergic conditions.

Return to the Yellow Card scheme case studies page or submit a report.