Interactions with Herbs

Asian ginseng  (Panax ginseng)
Ginseng was associated with a decrease in warfarin activity in a case study.¹ This report suggests that ginseng may affect parameters of bleeding. Therefore, people taking ticlopidine should consult with a physician knowledgeable about botanical medicines before taking Asian ginseng or eleuthero/Siberian ginseng (Eleutherococcus senticosus).

Dan shen (Salvia miltiorrhiza)
Dan shen, a Chinese herb, was associated with increased warfarin activity in two cases.^{2 3} Although warfarin acts differently from ticlopidine, both affect parameters of bleeding. Until more is known, people taking ticlopidine should use dan shen only under close medical supervision. Sage (Salvia officinalis), a plant relative of dan shen found in the West, has not been not associated with interactions involving warfarin.

Devil’s claw (Harpagophytum procumbens)
Devil’s claw was associated with purpura (bleeding under the skin) in a patient treated with warfarin.⁴ As with dan shen, until more is known, people taking ticlopidine should avoid taking devil’s claw concurrently.

Garlic (Allium sativum)
Garlic has been shown to help prevent atherosclerosis (hardening of the arteries), perhaps by reducing the ability of platelets to stick together.⁵ Interfering with the action of platelets results in an increase in the tendency toward bleeding⁶ and in theory could dangerously enhance the effect of ticlopidine. Standardised extracts of garlic have been associated with bleeding in people only on rare occasions.⁷ People taking ticlopidine should consult with a doctor before taking products containing standardised extracts of garlic or eating more than one clove of garlic daily.

Ginger (Zingiber officinale)
Ginger has been shown to reduce platelet stickiness in test tubes. Although there appear to be no reports of interactions with platelet inhibiting drugs, people should talk with a healthcare professional if they are taking a platelet inhibitor and wish to use ginger.⁸

Ginkgo biloba
Ginkgo extracts may reduce the ability of platelets to stick together, possibly increasing the tendency toward bleeding.⁹ In a rat study, a high intake of ginkgo increased the action of ticlopidine in a way that could prove dangerous if the same effect occurred in people.¹⁰ Standardised extracts of ginkgo have been associated with two cases of spontaneous bleeding, although the ginkgo extracts were not definitively shown to be the cause of the problem.^{11 12} People taking ticlopidine should use ginkgo extracts only under the supervision of a doctor.

Herbs containing coumarin-derivatives
Although there are no specific studies demonstrating interactions with platelet inhibitors, the following herbs contain coumarin-like substances that may cause bleeding and therefore interact with ticlopidine. These herbs include dong quai, fenugreek, horse chestnut, red clover, sweet clover, and sweet woodruff.

Quinine (Cinchona sp.)
Quinine, a chemical found in cinchona bark and available as a drug product, has been reported to increase warfarin activity.¹³ Although warfarin and ticlopidine are both considered “blood thinners,” they have significantly different actions. Therefore, it remains unclear whether the reported interaction between quinine and warfarin would occur between ticlopidine and quinine.

Salicylate-containing herbs
Like ticlopidine, salicylates interfere with the action of platelets. Various herbs, including meadowsweet (Filipendula ulmaria), poplar (Populus tremuloides),willow (Salix alba), and wintergreen (Gaultheria procumbens) contain salicylates. Though similar to aspirin, plant salicylates have been shown to have different actions in test tube studies.¹⁴ Furthermore, salicylates are poorly absorbed and likely do not build up to levels sufficient to cause negative interactions that aspirin might cause.¹⁵ No reports have been published of negative interactions between salicylate-containing plants and aspirin or aspirin-containing drugs.¹⁶ Therefore concerns about combining salicylate-containing herbs and any drug remain theoretical, and the risk of causing bleeding problems may be low.