Drug & supplement interaction

Procaine + Promethazine

Promethazine brand name: Phenergan.

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 Procaine and Promethazine 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.

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Interaction report

Procaine and Promethazine

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 Promethazine and Procaine 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.

Procaine safety at a glance

Procaine overall Use caution Procaine is a prescription anesthetic, not a proven supplement, and can cause allergic reactions and other side effects.
Pregnancy Likely Unsafe When used for self-medication; avoid using. Read the full pregnancy detail
Breastfeeding Use caution Safety of non-medical procaine products during breastfeeding is not established, so avoid them.

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

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

Why No Interaction Is Listed for Promethazine

Interactions in our licensed database are recorded against drug classes, not just single drug names. Promethazine is filed under 4 classifications — including phenothiazines, anticholinergic drugs, photosensitizing drugs. Procaine has documented interactions with 5 drug classes — the most serious being digoxin (lanoxin) (major), skeletal muscle relaxants (major) and succinylcholine (major) — and none of Promethazine’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

Procaine Does Interact With Other Medications

Procaine has 37 major, 19 moderate known drug interactions in our database — Promethazine isn’t one of them. If you take anything else, check it against the full list below.

Major 37 Moderate 19 No known interaction 2,774 (incl. Promethazine)
Taking anything else?

Check Another of Your Medications Against Procaine

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

What to actually watch for

What Procaine Itself Has Been Linked To

This is not an interaction — nothing below involves Promethazine. It is the side-effect record for Procaine on its own, from the licensed Natural Medicines monograph. If something new turns up after you add Procaine, this list is the first place to look.

  • Heartburn Additional detail

    “Orally, procaine can cause heartburn, migraines, and systemic lupus erythematosus (SLE) (6,99208).”

    Procaine · Natural Medicines adverse-effect record, reported in dyspepsia.

    2 sources cited
    1. 6. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
    2. 99208. Szatmári S, Bereczki D. Procaine treatments for cognition and dementia. Cochrane Database Syst Rev. 2008;(4):CD005993. DOI

    “Orally, procaine can cause heartburn (6).”

    Procaine · Natural Medicines adverse-effect record, reported in dyspepsia.

    1 source cited
    1. 6. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
  • Migraine Additional detail

    Recorded for Procaine in the same Natural Medicines adverse-effect record shown under Heartburn above.

Everything above comes from the Natural Medicines adverse-effect record for Procaine — expand a row for the licensed statement it rests on. We read the ADVERSE REACTIONS section of Promethazine’s FDA label too, and the two lists don’t meaningfully overlap — which is why no Promethazine column appears here.

Special populations

Procaine in Pregnancy & Breastfeeding

Pregnancy Likely Unsafe

When used for self-medication; avoid using.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

From our Q&A

Questions About Procaine or Promethazine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Procaine or Promethazine, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Promethazine

This page covers Procaine only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Promethazine page lists 83 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Henbane (major), Scopolia (major), Alfalfa (moderate) and Angel's Trumpet (moderate).

By severity: 3 major · 57 moderate · 23 minor.

From our pharmacist’s overview on the Promethazine page

“Promethazine (Phenergan) is a phenothiazine antihistamine used for allergies, nausea, and motion sickness, and it is strongly anticholinergic on its own, causing dry mouth, blurred vision, drowsiness, and constipation. That is why the 83 supplements and herbs on this list deserve real attention, starting with the three rated major.”

Reviewed by 2 · Jul 18, 2026

Open the Promethazine interaction page

One more smart check

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

We hold 2 real supplement products containing Procaine, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Procaine. Even though Procaine itself has no known interaction with Promethazine, 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 Procaine and Promethazine 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 Procaine
Top half

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

29 days ago today
Medication Promethazine
Steady interest

#2,040 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 Procaine reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Procaine and Promethazine records this page draws on were last updated July 11, 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 Procaine

What is Procaine?

  • Local anesthesia (medical/dental use)
  • Marketed 'anti-aging' supplements
  • General well-being and vitality claims
  • Mood and energy support (unproven)

Procaine is a synthetic local anesthetic (best known by the brand name Novocaine) used by doctors and dentists to numb tissue. It is not a true dietary supplement or herb, and the 'anti-aging' products built around it (such as GH3 or 'Gerovital') have weak evidence and real safety concerns. Talk to your pharmacist or doctor before using any product containing procaine.

Synthetic chemical compound (procaine hydrochloride) · Injectable solution (prescription), and in some products labeled 'procaine' or 'GH3' marketed as anti-aging supplements

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

Procaine: dosing

There is no established or recommended supplement dose for procaine. Because the benefits are unproven and the risks are real, many pharmacists would advise against using these products at all.

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

Read the full Procaine monograph & all interactions
Medication

About Promethazine

What Is Promethazine Used For?

Brand name: Phenergan

Promethazine is used for a wide range of conditions. Tablets, oral solution, and rectal suppositories (brands including Phenergan, Promethegan, and Phenadoz) are approved for seasonal and perennial allergic rhinitis, vasomotor rhinitis, allergic conjunctivitis, hives (urticaria), angioedema, dermographism, and allergic reactions to blood or plasma. They are also used for motion sickness (both prevention and active treatment), nausea and vomiting related to anesthesia and surgery, sedation, and as a helper medication alongside pain relievers after surgery.

Promethazine hydrochloride injection (brands including Phenergan and Promethazine HCl injection) is used for many of the same purposes but is reserved for situations where oral treatment is not possible — including allergic emergencies as an adjunct to epinephrine, sedation during labor, and as an aid during certain surgical procedures such as bronchoscopy and eye surgery.

Most-Reported Side Effects for Promethazine

From FAERS, the FDA’s public side-effect reporting system (22,614 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Dependence 3,586 reports
Nausea 2,646 reports
Vomiting 1,802 reports
Fatigue 1,496 reports
Diarrhea 1,341 reports
See full Promethazine drug information
Keep checking

Other Drugs & Procaine

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

37Major
19Moderate
0Minor
2,773No known interaction
37 Major 19 Moderate 2,773 No interaction
Major

37 interactions

Moderate

19 interactions

No interaction 2,773 drugs checked — show the list

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

Showing the 60 most looked-up of 2,773 medications checked with no known interaction — see the full Procaine list.

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

Procaine References

The 3 references that drive our Procaine 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. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
  2. McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
  3. Szatmári S, Bereczki D. Procaine treatments for cognition and dementia. Cochrane Database Syst Rev. 2008;(4):CD005993. DOI

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 Procaine and Promethazine Together: Common Questions

Is it safe to take Procaine with Promethazine?
We do not list a known interaction between Procaine and Promethazine. 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.
How was the Procaine and Promethazine combination checked?
Interactions in our licensed database are recorded against drug classes. Promethazine is filed under 4 classifications, and Procaine has documented interactions with 5 drug classes — none of Promethazine'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 Procaine interact with any other medications?
Yes. Procaine has 56 documented drug interactions in our database — Promethazine 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 Promethazine interact with any supplements?
Yes. Promethazine has documented interactions with 83 supplements in our database — Procaine is not one of them. The Promethazine 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

Procaine monograph Uses, safety profile, and every drug interaction in one place Promethazine drug information The full plain-English guide to this medication Promethazine supplement interactions Every supplement checked against Promethazine, 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 3 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Promethazine and Procaine?

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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.