Physician anesthesiologist at Stanford at Associated Anesthesiologists Medical Group
Richard Novak, MD is a Stanford physician board certified in anesthesiology and internal medicine.Dr. Novak is an Adjunct Clinical Professor in the Department of Anesthesiology, Perioperative and Pain Medicine at Stanford University, the Medical Director at Waverley Surgery Center in Palo Alto, California, and a member of the Associated Anesthesiologists Medical Group in Palo Alto, California.

An otherwise healthy 50-year-old female patient takes three herb pills daily: gingko, kava, and ginseng. What do you do when this patient needs elective surgery for an ACL reconstruction two days from now? Do you cancel surgery and stop the herbal medicines, or should you proceed?

My goal is to give you practical advice on how to proceed in the real world of anesthesia and surgical practice. We all know herbal medicines are out there. Do they matter? What is the evidence that herbal medicines affect surgical outcomes in an adverse way?

Many commonly used herbal medicines have side effects that affect drug metabolism, bleeding, and the central nervous system. In 2002 35% of Americans used complementary alternative medicine (CAM) therapies, and visits to CAM practitioners exceeded those to American primary care physicians (Tindle et al: Trends in use of complementary and alternative medicine by US adults: 1997-2002. Altern Ther Health Med 2005; 11:42). CAM practitioners include homeopathic medicine, meditation, art, music, or dance therapy, herbal medicines, dietary supplements, chiropractic manipulation, osteopathic medicine, massage, and acupuncture.

The finest review of herbal medicines and anesthesia is Chapter 33 in Miller’s Anesthesia, 7th Edition, 2009, authored by Ang-Lee, Yuan, and Moss. The authors write, “Many patients fail to volunteer information regarding herb and alternative medicine pills unless they are specifically asked about herbal medication use. Scientific knowledge in this area is still incomplete. There are no randomized, controlled trials that have evaluated the effects of prior herbal medicine use on the period immediately before, during and after surgery.” They go on to say, “preoperative use of herbal medicines has been associated with adverse perioperative events,” and “Because herbal medicines are classified as dietary supplements, they are not subject to preclinical animal studies, premarketing controlled clinical trials, or postmarketing surveillance. Under current law, the burden is shifted to the U.S. Food and Drug Administration (FDA) to prove products unsafe before they can be withdrawn from the market.”

The authors reviewed nine herbal medicines that have the greatest impact on perioperative patient care: echinacea, ephedra, garlic, Ginkgo biloba, ginseng, kava, saw palmetto, St. John’s wort, and valerian. These nine pills represent 50% of the herbal medicines sold in the United States.

The same authors published a paper entitled “Herbal Medicines and Perioperative Care.” (JAMA 2001; 286:208). The following table is reproduced from that journal article, and describes relevant effects, perioperative concerns, and recommendations for eight of the most common herbal medicines:

Boosts immunity. Allergic reactions, impairs immune suppressive drugs, can cause 
immune suppression when taken long-term, could impair wound 
healing. Discontinue as far in advance as possible, especially for transplant patients or those with liver dysfunction.

Ephedra (ma huang) Increases heart rate, increases blood pressure. Risk of heart attack, arrhythmias, stroke, interaction with other drugs, kidney stones. Discontinue at least 24 hours before surgery.

Garlic (ajo)
Prevents clotting. Risk of bleeding, especially when combined with other drugs that inhibit clotting. Discontinue at least 7 days before surgery.

Ginko (duck foot, maidenhair, silver apricot). Prevents clotting. Risk of bleeding, especially when combined with other drugs that inhibit clotting. Discontinue at least 36 hours before surgery.

Lowers blood glucose, inhibits clotting. Lowers blood-sugar levels. Increases risk of bleeding. Interferes with warfarin (an anti-clotting drug). Discontinue at least seven days before surgery.

Kava (kawa, awa, intoxicating pepper). Sedates, decreases anxiety. May increase sedative effects of anesthesia. Risks of addiction, tolerance and withdrawal unknown. Discontinue at least 24 hours before surgery.

St. John’s wort (amber, goatweed, Hypericum, klamatheweed). Inhibits re-uptake of neuro-transmitters (similar to Prozac). Alters metabolisms of other drugs such as cyclosporin (for transplant patients), warfarin, steroids, protease inhibitors (vs HIV). May interfere with many other drug.s Discontinue at least five days before surgery.

Sedates Could increase effects of sedatives. Long-term use could increase the amount of anesthesia needed. Withdrawal symptoms resemble Valium addiction If possible, taper dose weeks before surgery. If not, continue use until surgery. Treat withdrawal symptoms with benzodiazepines.

In their chapter in Miller’s Anesthesia, Ang-Lee, Yuan, and Moss recommend that, “In general, herbal medicines should be discontinued preoperatively. When pharmacokinetic data for the active constituents in an herbal medication are available, the timeframe for preoperative discontinuation can be tailored. For other herbal medicines, 2 weeks is recommended. However, in clinical practice because many patients require nonelective surgery, are not evaluated until the day of surgery, or are noncompliant with instructions to discontinue herbal medications preoperatively, they may take herbal medicines until the day of surgery. In this situation, anesthesia can usually proceed safely at the discretion of the anesthesiologist, who should be familiar with commonly used herbal medicines to avoid or recognize and treat complications that may arise.”

The American Society of Anesthesiologists have no official standards or guidelines on the preoperative use of herbal medications. Public and professional educational information released by the American Society of Anesthesiologists suggest that herbals be discontinued at least 2 to 3 weeks before surgery.

To return to our original question, what do you do when your otherwise healthy 50-year-old female patient has been taking gingko, kava, and ginseng up to two days prior to her ACL reconstruction surgery? Gingko can cause increased bleeding, kava can cause increased sedation, and ginseng can cause decreased blood sugars and increased bleeding. You discuss the predicament with the patient’s surgeon. He’s not concerned that a possible increased risk of bleeding will affect this knee surgery. You decide the increased level of sedation and the possible decreased blood sugar risks are not prohibitive. (If you were worried, you could cut back slightly on the amount of central nervous system depressant drugs you utilize, and also run a 5% dextrose solution in the patient’s IV.)

An alternative choice would be to cancel the surgery for 2 weeks while the patient remains herb-free. The surgeon asks you, “Is there any data that postponing the surgery for two weeks will decrease the complication rate?”

You answer honestly and say, “There is no data. The American Society of Anesthesiologists suggests that herbals be discontinued at least 2 to 3 weeks before surgery.”

The surgeon says, “I want to do the case tomorrow. There’s no data compelling me to delay for two weeks. I accept whatever increased bleeding risk there may be. I’ve never had a patient have a bleeding complication from a knee surgery.”

You proceed with the surgery the next day. The patient does well, and has no complications.

Surveys estimate that:
a) 22% to 32% of patients undergoing surgery use herbal medications (Tsen LC, et al: Alternative medicine use in presurgical patients. Anesthesiology 2000; 93:148);
b) 90% of anesthesiologists do not routinely ask about herbal medicine use (McKenzie AG: Current management of patients taking herbal medicines: A survey of anaesthetic practice in the UK. Eur J Anaesthesiol 2005; 22:597); and
c) more than 70% of patients are not forthcoming about their herbal medicine use during routine preoperative assessment (Kaye AD, et al: Herbal medications: Current trends in anesthesiology practice—a hospital survey. J Clin Anesth 2000; 12:468).

The frequent use of herbal medicines in perioperative patients is real. How big a problem is it? Nobody knows. How frequently does one of your patients have an unexpected problem of increased bleeding, increased sedation, decreased blood sugar, unexpected cardiac arrhythmia or angina, or decreased immune function?

For an ACL reconstruction in a healthy patient, gingko, kava, and ginseng may pose little risk. For a craniotomy on a 70-year-old with coronary artery disease and diabetes, gingko, kava, and ginseng bay pose an increased risk, and warrant postponing the surgery for 2 weeks after holding the herbal medicines.

My advice is to take a careful history of herb medicine use from your patients, know (or look it up if you don’t remember) the potential side effects of each herbal medicine, and then on a case-by-case basis decide if it really matters if the surgery should be cancelled for 2 weeks.

That’s what doctors do. That’s what anesthesia consultants do.


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Published in September 2017:  The second edition of THE DOCTOR AND MR. DYLAN, Dr. Novak’s debut novel, a medical-legal mystery which blends the science and practice of anesthesiology with unforgettable characters, a page-turning plot, and the legacy of Nobel Prize winner Bob Dylan.


In this debut thriller, tragedies strike an anesthesiologist as he tries to start a new life with his son.

Dr. Nico Antone, an anesthesiologist at Stanford University, is married to Alexandra, a high-powered real estate agent obsessed with money. Their son, Johnny, an 11th-grader with immense potential, struggles to get the grades he’ll need to attend an Ivy League college. After a screaming match with Alexandra, Nico moves himself and Johnny from Palo Alto, California, to his frozen childhood home of Hibbing, Minnesota. The move should help Johnny improve his grades and thus seem more attractive to universities, but Nico loves the freedom from his wife, too. Hibbing also happens to be the hometown of music icon Bob Dylan. Joining the hospital staff, Nico runs afoul of a grouchy nurse anesthetist calling himself Bobby Dylan, who plays Dylan songs twice a week in a bar called Heaven’s Door. As Nico and Johnny settle in, their lives turn around; they even start dating the gorgeous mother/daughter pair of Lena and Echo Johnson. However, when Johnny accidentally impregnates Echo, the lives of the Hibbing transplants start to implode. In true page-turner fashion, first-time novelist Novak gets started by killing soulless Alexandra, which accelerates the downfall of his underdog protagonist now accused of murder. Dialogue is pitch-perfect, and the insults hurled between Nico and his wife are as hilarious as they are hurtful: “Are you my husband, Nico? Or my dependent?” The author’s medical expertise proves central to the plot, and there are a few grisly moments, as when “dark blood percolated” from a patient’s nostrils “like coffee grounds.” Bob Dylan details add quirkiness to what might otherwise be a chilly revenge tale; we’re told, for instance, that Dylan taught “every singer with a less-than-perfect voice…how to sneer and twist off syllables.” Courtroom scenes toward the end crackle with energy, though one scene involving a snowmobile ties up a certain plot thread too neatly. By the end, Nico has rolled with a great many punches.

Nuanced characterization and crafty details help this debut soar.

Click on the image below to reach the Amazon link to The Doctor and Mr. Dylan:


Learn more about Rick Novak’s fiction writing at ricknovak.com by clicking on the picture below: