Ginseng (Panax ginseng)

Take 0.5–1 g up to 3 times a day for 6 weeks at a time, either by chewing the root, cooking it in a soup or stew, or taking it in tablet form.

Tablets are a convenient way of taking ginseng. Take for short-term stressful events.

The interaction between Panax ginseng (Asian ginseng) and albendazole is based on experimental evidence only. No interactions found.

Ginseng may contain oestrogenic compounds that might directly stimulate breast cancer growth and oppose the actions of competitive oestrogen receptor antagonists such as tamoxifen. However, there is some evidence that ginseng use before diagnosis might not adversely affect breast cancer survival.

One pharmacological study found that Panax quinquefolius (American ginseng) modestly decreased the effect of warfarin, whereas another study found that Panax ginseng (Asian ginseng) did not alter the effect of warfarin. Two case reports describe decreased warfarin effects, one with thrombosis, attributed to the use of ginseng (probably Panax ginseng). In a placebo-controlled study, 20 healthy subjects were given warfarin 5 mg daily for 3 days alone then again on days 15 to 17 of a 3-week course of Panax quinquefolius (American ginseng) 1 g twice daily. In the 12 subjects given ginseng, the peak INR was modestly reduced by 0.16, compared with a non-significant reduction of 0.02 in the 8 subjects given placebo. There was also a modest reduction in the AUC of warfarin. In this study, Panax quinquefolius root was ground and capsulated.1 Evidence from two earlier case reports supports a reduction in warfarin effect. A man taking warfarin long term, and also diltiazem, glyceryl trinitrate and salsalate, had a fall in his INR from 3.1 to 1.5 within 2 weeks of starting to take ginseng capsules (Ginsana) three times daily. This preparation contains 100 mg of standardised concentrated ginseng [probably Panax ginseng (Asian ginseng)] in each capsule. Within 2 weeks of stopping the ginseng his INR had risen again to 3.3.2 Another patient taking warfarin was found to have thrombosis of a prosthetic aortic valve, with a subtherapeutic INR of 1.4. Three months prior to this episode his INR had become persistently subtherapeutic, requiring a progressive increment in his warfarin dose. It was suggested that this might have been because he had begun using a ginseng product (not identified).3 In contrast, in a randomised, crossover study in 12 healthy subjects, ginseng capsules 1 g three times daily for 2 weeks did not affect either the pharmacokinetics or pharmacodynamics (INR) of a single 25-mg dose of warfarin taken on day 7. The brand of ginseng used was Golden Glow, each capsule containing an extract equivalent to 0.5 g of Panax ginseng (Asian ginseng) root.

Panax ginseng (Asian ginseng), Panax quinquefolius (American ginseng) and Eleutherococcus senticosus (Siberian ginseng) may interfere with the results of digoxin assays. A 74-year-old man who had been taking digoxin for many years (serum levels normally in the range 0.9 to 2.2 nanograms/mL) was found, during a routine check, to have digoxin levels of 5.2 nanograms/mL, but without evidence of toxicity or bradycardia or any other ECG changes.1 The levels remained high even when the digoxin was stopped. It turned out he had also been taking Eleutherococcus senticosus (Siberian ginseng) capsules. When the ginseng was stopped, the digoxin levels returned to the usual range, and digoxin was resumed. Later rechallenge with the ginseng caused a rise in his serum digoxin levels. No digoxin or digitoxin contamination was found in the capsules, and the authors of the report also rejected the idea that the eleutherosides (chemically related to cardiac glycosides) in ginseng might have been converted in vivo into digoxin, or that the renal elimination of digoxin might have been impaired, since the patient showed no signs of toxicity.

No interactions found.

Eleutherococcus senticosus (Siberian ginseng) does not appear to affect the metabolism of dextromethorphan. A study in 12 healthy subjects found that Eleutherococcus senticosus (Siberian ginseng), 485 mg twice daily for 14 days, did not significantly affect the metabolism of a single 30-mg dose of dextromethorphan.

Case reports describe headache, insomnia and tremulousness, which was attributed to the concurrent use of ginseng and phenelzine. A 64-year-old woman taking phenelzine [60 mg daily] developed headache, insomnia and tremulousness after taking Natrol High, a product containing ginseng,1,2 probably Eleutherococcus senticosus (Siberian ginseng). She had the same symptoms on another occasion after drinking a ginseng tea (type not stated), which she had used without problem before starting phenelzine.1 Three years later, while taking phenelzine 45 mg daily, she experienced the same symptoms and an increase in depression 72 hours after starting to take ginseng capsules (type not stated) and a herbal tea.2 Another depressed woman taking ginseng (type not stated) and bee pollen experienced relief of her depression and became active and extremely optimistic when she started to take phenelzine 45 mg daily, but this was accompanied by insomnia, irritability, headaches and vague visual hallucinations. When the phenelzine was stopped and then re-started in the absence of the ginseng and bee pollen, her depression was not relieved.

Eleutherococcus senticosus (Siberian ginseng) did not alter the pharmacokinetics of alprazolam, and Panax ginseng (Asian ginseng) did not alter midazolam metabolism. A study in 12 healthy subjects found that Eleutherococcus senticosus (Siberian ginseng), 485 mg twice daily for 15 days, did not significantly affect the pharmacokinetics of a single 2-mg dose of alprazolam given with the morning dose on day 14.1 Similarly, in 12 healthy subjects, Panax ginseng (Asian ginseng), 500 mg three times daily for 28 days, did not significantly affect the metabolism of oral midazolam 8 mg. The ginseng preparation used was standardised to 5% ginsenosides.2 These findings were repeated in a later study using the same criteria in 12 elderly healthy subjects

The stimulant effects of guarana, a caffeine-containing herb, appear to be additive to those of Panax ginseng (Asian ginseng). In a well-controlled single-dose study in healthy subjects, guarana extract 75 mg improved cognitive performance in ‘attention’ tasks and Panax ginseng (Asian ginseng) 200mg improved ‘memory’ tasks. The combination improved both attention and memory tasks, with no clear evidence for synergistic effects, except for better performance in the increased serial sevens subtractions compared with either drug alone. In this study, the ginseng extract was standardised to 4% of ginsenosides, and the guarana extract to 11 to 13% of xanthines (caffeine and theobromine), or a maximum of about 10 mg of caffeine per dose.

Panax ginseng (Asian ginseng) did not alter chlorzoxazone metabolism in one study. In a study in 12 healthy subjects, Panax ginseng (Asian ginseng) 500 mg three times daily for 28 days did not significantly affect the pharmacokinetics of chlorzoxazone 500 mg. The ginseng preparation used was standardised to 5% ginsenosides.1 These findings were repeated in a later study using the same criteria in 12 elderly healthy subjects.

Panax ginseng (Asian ginseng) increases the clearance of alcohol and lowers blood-alcohol levels. Fourteen healthy subjects, each acting as their own control, were given alcohol (72 g/65 kg as a 25% solution) with and without a Panax ginseng (Asian ginseng) extract (3 g/65 kg) mixed in with it. They drank the alcohol or the alcohol/ginseng mixture over a 45- minute period in 7 portions, the first four at 5-minute intervals and the next three at 10-minute intervals. Measurements taken 40 minutes later showed that the presence of the ginseng lowered bloodalcohol levels by an average of about 39%. The alcohol levels of 10 subjects were lowered by 32 to 51% by the ginseng; 3 showed reductions of 14 to 18% and one showed no changes at all.

Panax ginseng (Asian ginseng) did not alter caffeine metabolism in one study. Note that both ginseng and caffeine have stimulant effects. In a study in 12 healthy subjects Panax ginseng (Asian ginseng), 500 mg three times daily for 28 days, did not significantly affect the pharmacokinetics of caffeine 100 mg. The ginseng preparation used was standardised to 5% ginsenosides.1 These findings were repeated in a later study using the same criteria in 12 elderly healthy subjects.

In patients with diabetes taking various oral antidiabetics, Panax quinquefolius (American ginseng) and Panax ginseng (Asian ginseng) have both shown modest reductions in postprandial glucose levels after a glucose tolerance test, but Panax ginseng did not result in any improvement in diabetes control when given for 12 weeks. In a placebo-controlled crossover study, 19 patients with wellcontrolled type 2 diabetes were treated with oral Panax ginseng (Asian ginseng) 2 g three times daily 40 minutes before meals in addition to their usual treatment (antidiabetics and/or diet) for 12 weeks. The ginseng had no effect on glycosylated blood-glucose, which remained at about 6.5%, but it did slightly decrease the bloodglucose levels after a 75 g oral glucose tolerance test. All patients in the study were diet controlled: 5 patients received no additional treatment; 3 patients were taking a sulfonylurea; 3 patients were taking metformin; 5 patients were taking a sulfonylurea with metformin; 1 patient was taking a sulfonylurea with metformin and rosiglitazone; 1 patient was taking a sulfonylurea and rosiglitazone; and 1 patient was taking acarbose.1 In earlier studies by the same research group, single dose Panax quinquefolius (American ginseng) 3 to 9 g slightly reduced the postprandial blood-glucose concentrations by about 20 to 24% in patients with type 2 diabetes when given 40 minutes before or at the same time as a 25 g oral glucose challenge. These patients were being treated with diet alone, sulfonylureas, or sulfonylureas plus metformin.2,3 When comparing the effect between those receiving antidiabetics and those not, there was no difference, suggesting no specific drug interaction.