Another warning has been issued to adults and seniors who mix herbal remedies, over the counter supplements and prescription medications.
A study from the University of Hertfordshire in the UK found 44% of women and 22% of men surveyed mixed their prescription medications with herbal remedies and over the counter supplements.
Individuals may have changes in their metabolism and medication breakdown as they age causing variances in body absorption and efficacy of medications. Adding supplements or herbal remedies could cause unpredictable reactions.
These effects could include:
- Less efficacy of prescription medication causing poor blood pressure, sugar, heart rhythm control, for example)
- Enhanced active compounds of medications taken (possibly causing overdose)
- Nausea
- Vomiting
- Body aches
- Jaundice
- Blood thinning causing easy bleeding
- Renal failure
- Liver failure
- Anemia
- Mania and other personality changes
- and more
For example, St. John’s Wort could interfere with the effectiveness of one’s birth control and ginseng could worsen one's hypoglycemia if they are taking insulin.
Grapefruit juice could interfere with the metabolism of a statin, a popular medication used to decrease cholesterol. By raising its levels in the blood, one drink could cause a patient to have increased side effects such as muscle cramps and liver issues.
Iron supplements can interfere with one’s absorption of their thyroid medication, and ginkgo biloba, if taken with a blood pressure medication, could cause the blood pressure to drop even lower. Moreover it can increase bleeding if taken with an anticoagulant.
And if alcohol is mixed with any prescription medication, deadly side effects (such as respiratory depression when used with opiates) can ensue.
So the moral is, just because a supplement states is “natural,” or a frequently consumed food appears to be safe, its combination with medication could prove deadly.
Although the interactions are numerous, the AAFP created a table of common ones:
Herbal and Dietary Supplement–Drug Interactions
HERBAL OR DIETARY SUPPLEMENT |
DRUG |
COMMENT |
RECOMMENDATION* |
Patients taking oral anticoagulants |
|||
Cranberry (juice) |
Warfarin (Coumadin) |
Interaction possible based on seven reports of increased INR, although a clinical study showed no interactions4–7 |
Suspect an interaction if INR elevated |
Fish oil |
Warfarin |
Interaction possible, with case reports showing an elevated INR, although a clinical study showed no effect of fish oil on anticoagulation status8,9 |
Suspect an interaction if INR elevated |
Garlic |
Warfarin |
Interaction unlikely based on a clinical study that found garlic is relatively safe and poses no serious hemorrhagic risk for closely monitored patients taking warfarin oral anticoagulation therapy10 |
Suspect an interaction if bruising or bleeding occurs despite an appropriate INR |
One review found no case reports of interactions with garlic and warfarin11 |
|||
Ginkgo |
Warfarin |
Interaction possible, though controlled clinical studies show no effect of ginkgo on the kinetics or dynamics of warfarin12,13 |
Experts recommend caution, although available research does not support this conclusion |
Aspirin |
Interaction suspected based on four case reports of spontaneous bleeding14,15 |
Suspect an interaction if spontaneous bleeding occurs |
|
Ginseng |
Warfarin |
Interaction possible based on conflicting research findings |
Avoid combination if possible |
American ginseng (Panax quinquefolius)reduces blood concentrations of warfarin16,17 |
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Coadministration of warfarin with Asian ginseng (Panax ginseng) did not affect the pharmacokinetics or pharmacodynamics of warfarin18 |
|||
St. John’s wort |
Warfarin |
Interaction suspected based on decreases in INR in case reports and in a study in 12 healthy volunteers18 |
Evaluate warfarin response when St. John’s wort is initiated or stopped |
Vitamin E (> 400 IU daily) |
Warfarin |
Interaction suspected based on a single patient (with rechallenge), resulting in an increase in INR19 |
Evaluate warfarin response when vitamin E is used in combination |
One clinical trial showed no interaction20 |
|||
Patients taking cardiovascular medications |
|||
Eleuthero (Eleutherococcus senticosus) [corrected] |
Digoxin |
Possible increase in digoxin levels without clinical signs (case report)21 |
Monitor digoxin level when eleuthero is initiated or stopped [corrected] |
St. John’s wort |
Digoxin |
Suspected decrease in digoxin levels without clinical signs in a controlled study22 |
Monitor digoxin level when St. John’s wort is initiated or stopped |
Verapamil (Calan) |
Interaction suspected based on decreased bioavailability in a study in eight healthy volunteers23 |
Increase verapamil dose, if necessary, if diminished response occurs |
|
Statins |
Interaction suspected based on decreased plasma blood levels in a clinical study24 |
Monitor serum lipid levels after St. John’s wort is added |
|
Patients taking psychiatric medications |
|||
Ginkgo |
Atypical antidepressant (trazodone [Desyrel]) |
Interaction possible based on one case report of coma25 |
Evaluate for emotional and/or behavioral changes in patient response after ginkgo is initiated or stopped |
Ginseng |
Monoamine oxidase inhibitors |
Interaction possible based on two case reports of manic-like symptoms, headache, and tremulousness17 |
Avoid combination if possible |
St. John’s wort |
SSRIs |
Interaction suspected based on case reports of drowsiness or serotonin syndrome26 |
Taper off St. John’s wort when initiating an SSRI |
Benzodiazepines |
Interaction suspected based on pharmacokinetic studies showing decreased serum levels (25 to 50 percent) without clinical signs27–29 |
Adjust the dose of benzodiazepine as needed |
|
Tricyclic antidepressants |
Interaction possible based on decreased amitriptyline plasma levels but no clinical effects in a study of 12 depressed patients27,30 |
Monitor patient response after St. John’s wort is initiated or stopped |
INR = International Normalized Ratio; SSRI = selective serotonin reuptake inhibitor.
*— All recommendations have a strength of recommendation taxonomy (SORT) evidence rating of C (consensus, disease-oriented evidence, usual practice, expert opinion, or case series). For information about the SORT evidence rating system, see https://www.aafp.org/afpsort.xml.
Information from references 4 through 30.
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Daliah Wachs is a guest contributor to GCN news, her views and opinions, medical or otherwise, if expressed, are her own. Doctor Wachs is an MD, FAAFP and a Board Certified Family Physician. The Dr. Daliah Show , is nationally syndicated M-F from 11:00 am - 2:00 pm and Saturday from Noon-1:00 pm (all central times) at GCN.