Drug & supplement interaction

Pregnenolone + Granisetron

Granisetron brand names: Kytril, Sustol.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Pregnenolone and Granisetron in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the label for Granisetron states a food rule worth keeping to, and the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Pregnenolone and Granisetron

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Granisetron and Pregnenolone in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Pregnenolone safety at a glance

Pregnenolone overall Use caution It is a hormone with limited human safety data, so use only under guidance from a healthcare professional.
Pregnancy Avoid Hormone supplements should be avoided during pregnancy due to unknown risks.
Breastfeeding Avoid Not enough safety information exists, so avoid while breastfeeding.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Granisetron and Pregnenolone? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Granisetron

Interactions in our licensed database are recorded against drug classes, not just single drug names. Granisetron is filed under 3 classifications — serotonergic drugs, serotonergic drugs, oral drugs. Pregnenolone has documented interactions with 5 drug classes — the most serious being benzodiazepines (moderate), estrogens (moderate) and progesterone (moderate) — and none of Granisetron’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Pregnenolone Does Interact With Other Medications

Pregnenolone has 82 moderate known drug interactions in our database — Granisetron isn’t one of them. If you take anything else, check it against the full list below.

Moderate 82 No known interaction 2,748 (incl. Granisetron)
Taking anything else?

Check Another of Your Medications Against Pregnenolone

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

What to actually watch for

No Interaction Found — But Data Suggests Pregnenolone and Granisetron May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do.

  • Drowsiness Additional detail

    Pregnenolone

    “Orally, pregnenolone has been reported to cause restlessness, tiredness, sweating, and a case of cold extremities. Sleep problems, drowsiness, and tremor have also been reported; however, it not certain if these effects were due to pregnenolone.”

    Pregnenolone · Natural Medicines adverse-effect record, reported in common cold.

    3 sources cited
    1. 94026. Fung LK, Libove RA, Phillips J, Haddad F, Hardan AY.Brief report: an open-label study of the neurosteroid pregnenolone in adults with autism spectrum disorder. J Autism Dev Disord 2014;44(11):2971-7. PubMed
    2. 94032. Marx CE, Keefe RS, Buchanan RW, et al. Proof-of-concept trial with the neurosteroid pregnenolone targeting cognitive and negative symptoms in schizophrenia. Neuropsychopharmacology 2009;34(8):1885-903. PubMed
    3. 94031. Meieran SE, Reus VI, Webster R, Shafton R, Wolkowitz OM. Chronic pregnenolone effects in normal humans: attenuation of benzodiazepine-induced sedation. Psychoneuroendocrinology 2004;29(4):486-500. PubMed

    Granisetron

    Listed in the ADVERSE REACTIONS section of the FDA label for Granisetron. Read the label on DailyMed ›

  • Anxiety or restlessness Additional detail

    Pregnenolone

    “Orally, pregnenolone has been reported to cause depressive affect and increased appetite. Increased excitement, agitation, increased motor activity, and anorexia have also been reported; however, it is not certain if these effects were due to pregnenolone.”

    Pregnenolone · Natural Medicines adverse-effect record, reported in anorexia.

    2 sources cited
    1. 94026. Fung LK, Libove RA, Phillips J, Haddad F, Hardan AY.Brief report: an open-label study of the neurosteroid pregnenolone in adults with autism spectrum disorder. J Autism Dev Disord 2014;44(11):2971-7. PubMed
    2. 94031. Meieran SE, Reus VI, Webster R, Shafton R, Wolkowitz OM. Chronic pregnenolone effects in normal humans: attenuation of benzodiazepine-induced sedation. Psychoneuroendocrinology 2004;29(4):486-500. PubMed

    Granisetron

    Listed in the ADVERSE REACTIONS section of the FDA label for Granisetron. Read the label on DailyMed ›

  • Constipation Additional detail

    Pregnenolone

    “Orally, pregnenolone may cause diarrhea. Constipation has also been reported after oral use; however, it is not certain if this effect was due to pregnenolone.”

    Pregnenolone · Natural Medicines adverse-effect record, reported in constipation.

    1 source cited
    1. 94026. Fung LK, Libove RA, Phillips J, Haddad F, Hardan AY.Brief report: an open-label study of the neurosteroid pregnenolone in adults with autism spectrum disorder. J Autism Dev Disord 2014;44(11):2971-7. PubMed

    Granisetron

    Listed in the ADVERSE REACTIONS section of the FDA label for Granisetron. Read the label on DailyMed ›

  • Tiredness Additional detail

    Pregnenolone

    Recorded for Pregnenolone in the same Natural Medicines adverse-effect record shown under Drowsiness above.

    Granisetron

    Listed in the ADVERSE REACTIONS section of the FDA label for Granisetron. Read the label on DailyMed ›

  • Diarrhea Additional detail

    Pregnenolone

    Recorded for Pregnenolone in the same Natural Medicines adverse-effect record shown under Drowsiness above.

    Granisetron

    Listed in the ADVERSE REACTIONS section of the FDA label for Granisetron. Read the label on DailyMed ›

Reported for Pregnenolone but not commonly for Granisetron: sun sensitivity, increased appetite, muscle pain and a skin rash.

Effects for Granisetron come from the ADVERSE REACTIONS section of its FDA label; effects for Pregnenolone come from the Natural Medicines adverse-effect record, quoted above. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

How to take them

Some Granisetron Products Have a Food Rule — Pregnenolone Should Not Break It

At least one FDA label for a product containing Granisetron says to take it on an empty stomach. Most supplements — Pregnenolone included — are taken with a meal, so the easy mistake is swallowing both together at breakfast. Where that rule applies, keep Granisetron on its own and move Pregnenolone to a meal later in the day.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Granisetron products can carry different directions, and extended-release forms often differ from immediate-release ones. The label we read is quoted below — check the directions on your own box or bottle, or ask your pharmacist, for how to take the exact product you were given.

Recommended Dosage ( 2.2 ): The recommended dosage in adults is 10 mg administered as a single subcutaneous injection at least 30 minutes before the start of emetogenic chemotherapy on Day 1.

From the Dosage and Administration section of the FDA label we read for Granisetron — where that label names a specific product, the instruction is that product's. Read the label on DailyMed ›

A food rule is not an interaction — it is about how much of the medicine you absorb. The directions that came with your own product, and your pharmacist, outrank anything on this page.

Everything else you take

See Every Supplement That Interacts With Granisetron

This page covers Pregnenolone only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Granisetron page lists 38 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Lithium (major), 5-htp (moderate), Acetyl-l-carnitine (moderate) and Ayahuasca (moderate).

By severity: 2 major · 25 moderate · 11 minor.

From our pharmacist’s overview on the Granisetron page

“Granisetron (Kytril, Sustol) blocks serotonin signals to stop nausea from chemotherapy and surgery, and this is a list that warrants real caution before you add a supplement to it. Most of the entries raise serotonin themselves, and stacking them on a serotonin-acting drug can push toward serotonin syndrome, a dangerous overload of tha…”

Reviewed by 2 · Jul 18, 2026

Open the Granisetron interaction page

One more smart check

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

We hold 303 real supplement products containing Pregnenolone, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Pregnenolone. Even though Pregnenolone itself has no known interaction with Granisetron, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Pregnenolone and Granisetron 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 Pregnenolone
Top half

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

29 days ago today
Medication Granisetron
Steady interest

#1,988 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.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Pregnenolone reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Pregnenolone and Granisetron records this page draws on were last updated July 10, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Pregnenolone

What is Pregnenolone?

Pregnenolone
  • Memory and cognitive support
  • Anxiety and stress
  • Anti-aging
  • Fatigue and low energy
  • Mood support

Pregnenolone is a hormone your body makes naturally and a building block for other hormones like cortisol, DHEA, estrogen, and testosterone. It is sold as a supplement for memory, mood, and anti-aging, but solid human evidence for these uses is very limited. Because it is a hormone, talk with your pharmacist or doctor before using it.

Naturally produced in the body; supplements are made synthetically (often from plant sterols like those in soy or wild yam) · Capsules, tablets, sublingual tablets, creams

An interaction check asks whether these two react with each other — it does not ask whether Pregnenolone is a good idea for someone in your situation. Here is what our Pregnenolone record says about it on its own.

Pregnenolone: dosing

There is no well-established or officially recommended dose for pregnenolone. Products vary widely in strength and form, and "more" is not safer with a hormone supplement.If your healthcare provider agrees you should try it, follow the directions on the product label and use the lowest amount that seems reasonable. Do not assume a higher dose works better.

From our Pregnenolone monograph — the full record covers uses, side effects and every documented interaction.

Read the full Pregnenolone monograph & all interactions
Medication

About Granisetron

What Is Granisetron Used For?

Brand names: Kytril, Sustol

Granisetron is used to prevent nausea and vomiting linked to emetogenic (nausea-causing) cancer chemotherapy — including high-dose cisplatin — and radiation therapy, including total body irradiation and fractionated abdominal radiation. Granisetron hydrochloride tablets and Granisol oral solution are approved for both the chemotherapy and radiation indications. Sancuso skin patch is approved for prevention of nausea and vomiting in adults receiving moderately and/or highly emetogenic chemotherapy regimens of up to 5 consecutive days.

Granisetron hydrochloride injection (intravenous) is also used to prevent and treat postoperative nausea and vomiting in adults. Sustol (subcutaneous injection) is used in combination with other anti-nausea medicines in adults specifically for the prevention of acute and delayed nausea and vomiting associated with moderately emetogenic chemotherapy or anthracycline and cyclophosphamide combination chemotherapy regimens.

See full Granisetron drug information
Keep checking

Other Drugs & Pregnenolone

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

0Major
82Moderate
0Minor
2,747No known interaction
82 Moderate 2,747 No interaction
Moderate

82 interactions

Showing 60 of 82 moderate interactions — see all 82 on the Pregnenolone page.

No interaction 2,747 drugs checked — show the list

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

Showing the 60 most looked-up of 2,747 medications checked with no known interaction — see the full Pregnenolone list.

See the full Pregnenolone interactions page
See every supplement checked against Granisetron, ranked by severity
Evidence & sources

Pregnenolone References

The 6 references that drive our Pregnenolone monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Devlin TM, ed. Textbook of Biochemistry With Clinical Correlations. third ed. New York: Wiley-Liss Inc., 1992.
  2. Fung LK, Libove RA, Phillips J, Haddad F, Hardan AY.Brief report: an open-label study of the neurosteroid pregnenolone in adults with autism spectrum disorder. J Autism Dev Disord 2014;44(11):2971-7. PubMed
  3. Brown ES, Park J, Marx CE, et al. A randomized, double-blind, placebo-controlled trial of pregnenolone for bipolar depression. Neuropsychopharmacology 2014;39(12):2867-73. PubMed
  4. Ritsner MS, Gibel A, Shleifer T, et al. Pregnenolone and dehydroepiandrosterone as an adjunctive treatment in schizophrenia and schizoaffective disorder: an 8-week, double-blind, randomized, controlled, 2-center, parallel-group trial. J Clin Psychiatry 20 PubMed
  5. Meieran SE, Reus VI, Webster R, Shafton R, Wolkowitz OM. Chronic pregnenolone effects in normal humans: attenuation of benzodiazepine-induced sedation. Psychoneuroendocrinology 2004;29(4):486-500. PubMed
  6. Marx CE, Keefe RS, Buchanan RW, et al. Proof-of-concept trial with the neurosteroid pregnenolone targeting cognitive and negative symptoms in schizophrenia. Neuropsychopharmacology 2009;34(8):1885-903. PubMed

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Pregnenolone and Granisetron Together: Common Questions

Is it safe to take Pregnenolone with Granisetron?
We do not list a known interaction between Pregnenolone and Granisetron. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Do Pregnenolone and Granisetron have any of the same side effects?
Yes — our sources link each of them separately to 5 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
Should I take Pregnenolone and Granisetron at the same time of day?
At least one FDA label for a product containing Granisetron says to take it on an empty stomach, and supplements are usually taken with a meal — so taking them together at breakfast is the easy mistake. Where that applies, keep Granisetron on its own and move Pregnenolone to a meal later in the day. Food instructions belong to the product rather than the ingredient, so check the directions on your own box. This is about absorption, not an interaction.
How was the Pregnenolone and Granisetron combination checked?
Interactions in our licensed database are recorded against drug classes. Granisetron is filed under 3 classifications, and Pregnenolone has documented interactions with 5 drug classes — none of Granisetron's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Pregnenolone interact with any other medications?
Yes. Pregnenolone has 82 documented drug interactions in our database — Granisetron is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Granisetron interact with any supplements?
Yes. Granisetron has documented interactions with 38 supplements in our database — Pregnenolone is not one of them. The Granisetron interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

Pregnenolone monograph Uses, safety profile, and every drug interaction in one place Granisetron drug information The full plain-English guide to this medication Granisetron supplement interactions Every supplement checked against Granisetron, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 6 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Granisetron and Pregnenolone?

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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.