The potential toxic combination of grapefruit juice and sildenafil

Recent investigations have shown a potential growth in the sales of Grapefruit Juice (GFJ). GFJ contains furanocoumarins, which are potent mechanism-based inhibitors of CYP3A4. Sildenafil, used for erectile dysfunction is metabolized by CYP3A4, so the aim of our review was to understand the interaction between the ingestion of grapefruit juice and the treatment with sildenafil. In August 2018–March 2019 we performed a search in the electronic database PubMed (MEDLINE). The search terms were ‘sildenafil’ AND ‘grapefruit’; ‘sildenafil’ AND ‘naringin’. We searched for studies published without temporal limits, and in English, French, or Spanish. The literature search yielded 12 publications but the review included 2 articles. Studies were published in 2001 and 2002: 1 was settled in Germany, 1 in USA. In both the studies grapefruit led to an increase of peak concentration (Cmax) of sildenafil in plasma. One author showed that grapefruit juice increased the mean oral bioavailability of sildenafil by 23%. Concluding, the important growth in grapefruit juice consumption should be carefully considered by pharmacists and health professionals. Patients undergoing a treatment with sildenafil should be educated about potential adverse reactions