Drug & supplement interaction

African Wild Potato + Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine

Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine brand name: Colrex.

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

Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine falls into 2 drug categories that African Wild Potato can interact with; the most serious is rated moderate. In vitro research shows that African wild potato extract inhibits cytochrome P450 1A2 (CYP1A2).

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions2
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

African Wild Potato and Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

African Wild Potato interacts with whole categories of medication. Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine falls into 2 of those categories, so it can interact with African Wild Potato in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES

1 of 2

Why this applies to Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine

Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine falls under CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES — the group African Wild Potato interacts with.

In vitro research shows that African wild potato extract inhibits cytochrome P450 1A2 (CYP1A2). However, this effect has yet to be reported in humans. Until more is known, use with caution. Theoretically, concomitant use of African wild potato with CYP1A2 substrates might increase the risk for adverse effects from these substrates. Some of these drugs include amitriptyline (Elavil), haloperidol (Haldol), ondansetron (Zofran), propranolol (Inderal), theophylline (Theo-Dur, others), verapamil (Calan, Isoptin, others), and others.
Severity Moderate Likelihood Possible Evidence D

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

This is one of those cautions that comes only from test-tube studies, not from real people. In the lab, African Wild Potato seemed to slow down a liver enzyme called CYP1A2. This combination product (Colrex) is a mix of acetaminophen, chlorpheniramine, codeine, and phenylephrine. CYP1A2 isn't the main pathway for most of these ingredients, so any real-world effect is likely to be small.

In theory, if that enzyme were blocked, certain pieces could linger a bit longer, which might add to common side effects like drowsiness, dizziness, dry mouth, or constipation. Since this is based only on lab data and the codeine portion is already sedating, I'd play it safe. Please check with your pharmacist or doctor before pairing them, especially if you feel extra sleepy.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Fasinu PS, Gutmann H, Schiller H, Bouic PJ, Rosenkranz B. The potential of Hypoxis hemerocallidea for herb-drug interaction. Pharm Biol. 2013 Dec;51(12):1499-507.
Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

2 of 2

Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine also falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES.

In vitro evidence shows that African wild potato extract can inhibit cytochrome P450 3A4 (CYP3A4) enzyme activity by up to 86%. Theoretically, African wild potato might increase levels of drugs metabolized by CYP3A4. However, in human research, African wild potato does not seem to affect the pharmacokinetics of Efavirenz, a CYP3A4 substrate. Until more is known, use African wild potato cautiously or avoid in patients taking drugs metabolized by CYP3A4. Some drugs metabolized by CYP3A4 include lovastatin (Mevacor), ketoconazole (Nizoral), itraconazole (Sporanox), fexofenadine (Allegra), triazolam (Halcion), and numerous others.
Severity Moderate Likelihood Possible Evidence D

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 wrinkle with this cold-and-cough combo: the codeine part is a prodrug. Your body has to convert it (mostly through a different enzyme, CYP2D6) into morphine to relieve pain or quiet a cough. The lab concern here is that African Wild Potato can block CYP3A4, and codeine also runs partly through that pathway. In theory, slowing CYP3A4 could shift how codeine is handled, possibly nudging up the morphine-like effects such as drowsiness, dizziness, constipation, or slowed breathing.

I want to be honest, though: this is based only on test-tube data, and in actual human studies this plant didn't change levels of a similar CYP3A4 drug. So the real-world risk looks small. Still, since codeine is sedating, please check with your pharmacist or doctor before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Jalloh MA, Gregory PJ, Hein D, et al. Dietary supplement interactions with antiretrovirals: a systematic review. Int J STD AIDS. 2017 Jan;28(1):4-15. 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

African Wild Potato Also Interacts With Other Medications

African Wild Potato has 1,004 moderate known drug interactions in our database — the Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine one above is among them. If you take anything else, check it against the full list below.

Moderate 1,004 No known interaction 1,826 (incl. Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine)
Taking anything else?

Check Another of Your Medications Against African Wild Potato

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

Everything else you take

See Every Supplement That Interacts With Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine

This page covers African Wild Potato only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine page lists 338 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: 1,4-butanediol (major), Activated Charcoal (major), Asarabacca (major), Beer (major) and Ephedra (major).

By severity: 18 major · 275 moderate · 45 minor.

From our pharmacist’s overview on the Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine page

“Someone taking Colrex is usually fighting a miserable cold, and cold season is also when people reach for herbal sleep aids and energy boosters, which is exactly where this list bites hardest. Colrex combines acetaminophen, chlorpheniramine, codeine, and phenylephrine, and 18 of its 338 supplement interactions rate major, enough to war…”

Reviewed by 2 · Jul 18, 2026

Open the Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine interaction page

One more smart check

Taking African Wild Potato as Part of a Dietary Supplement Product? Check It for Interactions

We hold 1 real supplement products containing African Wild Potato, each one broken down to its full ingredient list — and combination products often carry several ingredients besides African Wild Potato. Your product may carry other ingredients that interact with Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine too, on top of African Wild Potato — 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 African Wild Potato and Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine 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 African Wild Potato
Top half

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

29 days ago today
Medication Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine
Top 10%

#281 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 African Wild Potato

What is African Wild Potato?

  • Immune support
  • Prostate and urinary symptoms
  • Inflammation
  • General tonic/wellness
  • Skin conditions

African Wild Potato (Hypoxis hemerocallidea) is a southern African plant traditionally used as a tonic and for immune, prostate, and inflammatory complaints. Human evidence for these uses is very limited, and safety—especially during pregnancy, breastfeeding, or with serious illness—is not well established. Talk to a pharmacist or doctor before using it.

Read the full African Wild Potato monograph & all interactions
Keep checking

Other Drugs & African Wild Potato

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

0Major
1,004Moderate
0Minor
1,825No known interaction
1,004 Moderate 1,825 No interaction
Moderate

1,004 interactions

Showing 60 of 1,004 moderate interactions — see all 1,004 on the African Wild Potato page.

No interaction 1,825 drugs checked — show the list

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

Showing the 60 most looked-up of 1,825 medications checked with no known interaction — see the full African Wild Potato list.

See the full African Wild Potato interactions page
See every supplement checked against Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine, 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
African Wild Potato monograph › Uses, safety, and every drug interaction in one place Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine supplement interactions › Every supplement checked against Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine, 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 Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking African Wild Potato and Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine Together: Common Questions

Can you take African Wild Potato with Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
Why are there 2 interactions listed for African Wild Potato and Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine?
Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine belongs to more than one drug category, and African Wild Potato interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the African Wild Potato and Acetaminophen, Chlorpheniramine, Codeine, Phenylephrine interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

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

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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.