Aspirin/clopidogrel/herbal medicines interaction: Stent thrombosis: 3 case reports

Three patients developed stent thrombosis due to a drug interaction between dual anti-aggregant therapy with aspirin and clopidogrel and a herbal medicine containing Avena sativa, Panax ginseng and Tribulus terrestris [durations of treatment to reactions onset not stated; not all routes, dosages and frequencies stated].

A 45-year-old man began receiving aspirin 100mg and clopidogrel 75mg following coronary stenting of the proximal left anterior descending artery. One year later, he presented to the emergency department with chest pain. Coronary angiography revealed total stent occlusion. It was revealed that he had been taking up to 2 doses per day of a herbal medicine containing A. sativa, P. ginseng and T. terrestris for the past 3 months. He underwent balloon dilatation to fully open the vessel. He was advised not to use herbal medicines, and was discharged. No problems were observed after 4 months of follow-up.

A 53-year-old woman underwent stenting of the circumflex artery, and began receiving aspirin 100mg and clopidogrel 75mg. Three months later, she was admitted to the emergency room with chest pain and elevated cardiac enzymes. Stent thrombosis was seen on coronary angiography. She reported taking up to 2 doses per day of a herbal preparation containing A. sativa, P. ginseng and T. terrestris for the past 3 months. She underwent successful balloon angioplasty, and was discharged with the advice to stop using herbal medicines. At last follow-up, no problems were observed.

A 62-year-old man started receiving aspirin 100mg and clopidogrel 75mg following stenting of the circumflex artery. Three months later, he was hospitalised with chest pain. Coronary angiography revealed 98% stenosis inside the stent. He had been taking a herbal medicine containing A. sativa, P. ginseng and T. terrestris for the past 3 months. Balloon angioplasty was performed to open the vessel. He was advised against using herbal medicines, and was discharged. At last follow-up, no problems were observed.Author CommentStent thrombosis may be caused by interactions between herbal combination (Tribulus terrestris, Avena sativa and Panax ginseng) and clopidogrel in these patients under dual antiaggregant therapy.

References

1. Vatankulu MA, Tasal A, Erdogan E, Goktekin O.Three case reports of the use of herbal combinations resulted in stent thrombosis: Herbal combinations; friend or foe?. Turk Kardiyoloji Dernegi Arsivi: Turk Kardiyoloji Derneginin Yayin Organidir 40: 265-268, No. 3, Apr 2012. Available from: URL: http://dx.doi.org/10.5543/tkda.2012.84565. - Turkey.