Drug & supplement interaction

Blond Psyllium + Carbidopa, Levodopa

Carbidopa, Levodopa brand names: Sinemet CR, Sinemet, Rytary, Dhivy.

Minor Interaction
Medically reviewed by · Updated September 2026
The bottom line Minor

Blond Psyllium has a minor interaction with Carbidopa, Levodopa. Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.

Read the full interaction report
SeverityMinor
LikelihoodPossible
EvidenceB
What do Severity, Likelihood & Evidence mean?
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Interaction report

Blond Psyllium and Carbidopa, Levodopa

Here is the interaction we found between these two, with the evidence behind it.

Minor

ORAL DRUGS

Why this applies to Carbidopa, Levodopa

Carbidopa, Levodopa falls under ORAL DRUGS — the group Blond Psyllium interacts with.

Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.
Psyllium seems to have variable effects on drug absorption. To avoid changes in absorption, take psyllium 30-60 minutes after oral medications. Animal research shows that blond psyllium delays and increases the absorption of metformin and ethinyl estradiol. Conversely, case reports and animal research suggest that blond psyllium might reduce absorption of lithium, digoxin, olanzapine, and carbamazepine. Finally, some pharmacokinetic studies show that psyllium does not affect the absorption of levothyroxine or warfarin.
Severity Minor Likelihood Possible Evidence B

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the simple version: psyllium is a thick, gel-forming fiber, and when it sits in your gut alongside a pill, it can sometimes slow down or change how much of that pill gets absorbed. With carbidopa/levodopa, timing actually matters more than usual, because this medicine works best when it gets into your bloodstream smoothly and predictably. If absorption gets a little blunted or delayed, you might notice your dose feeling weaker or your Parkinson's symptoms (tremor, stiffness, slowness) creeping back before your next dose.

The good news is this is rated minor and the evidence is on the weaker side, so it's not a reason to worry. A simple fix helps a lot: separate them by taking psyllium about 30 to 60 minutes after your levodopa. Run your exact schedule by your pharmacist or doctor before changing anything.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  2. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  3. Covington TR, et al. Handbook of Nonprescription Drugs. 11th ed. Washington, DC: American Pharmaceutical Association, 1996.
  4. Robinson DS, Benjamin DM, McCormack JJ. Interaction of warfarin and nonsystemic gastrointestinal drugs. Clin Pharmacol Ther 1971;12:491-5. PubMed
  5. Garcia JJ, Fernandez N, Diez MJ, et al. Influence of two dietary fibers in the oral bioavailability and other pharmacokinetic parameters of ethinyloestradiol. Contraception 2000;62:253-7. PubMed
  6. Semen plantaginis in: WHO Monographs on Selected Medicinal Plants, volume 1. World Health Organization, Geneva, 1999. Available at http://apps.who.int/medicinedocs/en/d/Js2200e/. Accessed November 26, 1026.
  7. Diez R, Garcia JJ, Diez MJ, Sierra M, Sahagun AM, Fernandez N. Influence of Plantago ovata husk (dietary fiber) on the bioavailability and other pharmacokinetic parameters of metformin in diabetic rabbits. BMC Complement Altern Med. 2017 Jun 7;17(1):298. PubMed
  8. Chiu AC, Sherman SI. Effects of pharmacological fiber supplements on levothyroxine absorption. Thyroid. 1998;8(8):667-71. PubMed
  9. Merrick C, Madden CA, Capurso NA. A Case of Blunted Orally Disintegrating Olanzapine Effect Due to Coadministered Psyllium. J Clin Psychiatry 2021;82(2):20cr13633. PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Blond Psyllium Also Interacts With Other Medications

Blond Psyllium has 23 moderate, 2,001 minor known drug interactions in our database — the Carbidopa, Levodopa one above is one of them. If you take anything else, check it against the full list below.

Moderate 23 Minor 2,001 No known interaction 806 (incl. Carbidopa, Levodopa)
Taking anything else?

Check Another of Your Medications Against Blond Psyllium

Covers the 2,830 medications we’ve checked against Blond Psyllium. Pick one to open its full report.

Everything else you take

See Every Supplement That Interacts With Carbidopa, Levodopa

This page covers Blond Psyllium only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Carbidopa, Levodopa page lists 43 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Branched-chain Amino Acids (bcaa) (major), Cowhage (major), Indian Snakeroot (major) and Magnesium (major).

By severity: 8 major · 24 moderate · 11 minor.

From our pharmacist’s overview on the Carbidopa, Levodopa page

“Carbidopa/levodopa (Sinemet, Rytary) anchors Parkinson's treatment, and because symptom control hinges on how much levodopa actually reaches the brain, the 43 supplements and herbs on this list deserve real respect before you add any of them. Eight carry a major rating, and almost all of the serious entries weaken the drug rather than…”

Reviewed by 2 · Jul 18, 2026

Open the Carbidopa, Levodopa interaction page

One more smart check

Taking Blond Psyllium as Part of a Dietary Supplement Product? Check It for Interactions

We hold 97 real supplement products containing Blond Psyllium, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Blond Psyllium. Your product may carry other ingredients that interact with Carbidopa, Levodopa too, on top of Blond Psyllium — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Blond Psyllium and Carbidopa, Levodopa Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Blond Psyllium
Top half

#494 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Carbidopa, Levodopa
Top 5%

#76 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Supplement

About Blond Psyllium

What is Blond Psyllium?

Blond Psyllium
  • Constipation relief
  • Diarrhea and loose stools
  • High cholesterol
  • Digestive/gut health
  • Blood sugar support
  • Feeling fuller for weight management

Blond psyllium is a soluble fiber from the seed husks of Plantago ovata, and it is one of the better-studied fiber supplements. It can help with both constipation and diarrhea and may modestly lower cholesterol and blood sugar. It is generally well tolerated when taken with plenty of water, but always start low and check with your pharmacist or doctor first.

Read the full Blond Psyllium monograph & all interactions
Medication

About Levodopa and Carbidopa

What Is Levodopa and Carbidopa Used For?

Brand names: Sinemet CR, Sinemet, Rytary, Dhivy

Levodopa and carbidopa is used to treat Parkinson's disease, post-encephalitic parkinsonism (parkinsonism that develops after a brain infection), and symptomatic parkinsonism that can follow carbon monoxide or manganese poisoning. These indications are shared across the oral tablet, orally disintegrating tablet, extended-release tablet, and extended-release capsule formulations (including Sinemet, Rytary, Crexont, and generic products).

DUOPA — a carbidopa/levodopa suspension given through a tube directly into the small intestine — is specifically indicated for the treatment of motor fluctuations in patients with advanced Parkinson's disease. This is a product-specific indication and does not apply to the oral forms.

See full Levodopa and Carbidopa drug information
Keep checking

Other Drugs & Blond Psyllium

Browse every other medication we’ve checked against Blond Psyllium — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
23Moderate
2,001Minor
805No known interaction
23 Moderate 2,001 Minor 805 No interaction
Moderate

23 interactions

Minor

2,001 interactions

Showing 60 of 2,001 minor interactions — see all 2,001 on the Blond Psyllium page.

No interaction 805 drugs checked — show the list

We also checked Blond Psyllium against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 805 medications checked with no known interaction — see the full Blond Psyllium list.

See the full Blond Psyllium interactions page
See every supplement checked against Carbidopa, Levodopa, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Blond Psyllium monograph › Uses, safety, and every drug interaction in one place Carbidopa, Levodopa supplement interactions › Every supplement checked against Carbidopa, Levodopa, ranked by severity Levodopa and Carbidopa drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Blond Psyllium and Carbidopa, Levodopa Together: Common Questions

Can you take Blond Psyllium with Carbidopa, Levodopa?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Blond Psyllium and Carbidopa, Levodopa interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Carbidopa, Levodopa and Blond Psyllium?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.