Syrian Rue + Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine
Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine brand name: Theracaps.
Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine falls into 5 drug categories that Syrian Rue can interact with; the most serious is rated moderate. Theoretically, Syrian rue might increase the risk of serotonergic adverse effects, including serotonin syndrome, when taken with serotonergic drugs.
Read the full interaction reportSyrian Rue and Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine
These two interact in 5 distinct ways. Each one is explained separately below.
Why Are There 5 Interactions?
Syrian Rue interacts with whole categories of medication. Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine falls into 5 of those categories, so it can interact with Syrian Rue in 5 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).
SEROTONERGIC DRUGS
1 of 5Why this applies to Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine
Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine falls under SEROTONERGIC DRUGS — the group Syrian Rue interacts with.
Syrian rue contains harmaline and harmine, which have demonstrated strong, reversible inhibition of monoamine oxidase (MAO) A and weak inhibition of MAO B in animal and in vitro research. This may increase the risk for adverse effects with serotonergic drugs.
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.
This combination product (Theracaps) contains dextromethorphan, the cough suppressant, and that is the piece I want to flag here. Dextromethorphan raises serotonin activity in the brain. Syrian Rue acts like an MAO inhibitor, which slows the breakdown of serotonin. Stacking the two could, in theory, push serotonin too high and trigger what we call serotonin syndrome (agitation, a racing heart, sweating, shivering, muscle twitching, or confusion). The phenylpropanolamine in this product also worries me with an MAOI, since that pairing can spike blood pressure.
To be fair, this concern is based mostly on lab and animal data, not strong human studies. Still, because Syrian Rue is risky on its own, please check with your pharmacist or doctor before combining them.
- Kawanishi, K., Hashimoto, Y., Fujiwara, M., Kataoka, Y., and Ueki, S. Pharmacological characteristics of abnormal behavior induced by harmine with special reference to tremor in mice. J Pharmacobiodyn 1981;4(7):520-527. PubMed
- Herraiz, T., Gonzalez, D., Ancin-Azpilicueta, C., Aran, V. J., and Guillen, H. beta-Carboline alkaloids in Peganum harmala and inhibition of human monoamine oxidase (MAO). Food Chem Toxicol 2010;48(3):839-845. PubMed
- Fuller, R. W., Wong, C. J., and Hemrick-Luecke, S. K. MD 240928 and harmaline: opposite selectivity in antagonism of the inactivation of types A and B monoamine oxidase by pargyline in mice. Life Sci 1986;38(5):409-412. PubMed
- Abdel-Fattah, A. F., Matsumoto, K., Murakami, Y., Adel-Khalek, Gammaz H., Mohamed, M. F., and Watanabe, H. Central serotonin level-dependent changes in body temperature following administration of tryptophan to pargyline- and harmaline-pretreated rats. Ge PubMed
- Bergstrom, M., Westerberg, G., and Langstrom, B. 11C-harmine as a tracer for monoamine oxidase A (MAO-A): in vitro and in vivo studies. Nucl Med Biol 1997;24(4):287-293. PubMed
- Gerardy, J. Effect of moclobemide on rat brain monoamine oxidase A and B: comparison with harmaline and clorgyline. Prog Neuropsychopharmacol Biol Psychiatry 1994;18(4):793-802.
- Sacher, J., Houle, S., Parkes, J., Rusjan, P., Sagrati, S., Wilson, A. A., and Meyer, J. H. Monoamine oxidase A inhibitor occupancy during treatment of major depressive episodes with moclobemide or St. John's wort: an [11C]-harmine PET study. J Psychiatry
CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES
2 of 5Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine also falls under CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES.
Syrian rue contains beta-carboline alkaloids, including harmine, harmaline, harmalol, harmol, and harmane. In vitro research suggests that these beta-carboline alkaloids can inhibit CYP2D6 enzymes.
Interaction 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..
This combo product (Theracaps) contains dextromethorphan, the cough suppressant, and that's the ingredient I'd watch here. Dextromethorphan is cleared from your body mainly by a liver enzyme called CYP2D6. Lab studies suggest the harmala alkaloids in Syrian Rue can block that enzyme, so in theory the dextromethorphan could build up to higher levels than usual.
If that happens, you might notice more dizziness, drowsiness, confusion, or even a jittery, overstimulated feeling. There's an added worry: Syrian Rue acts like an MAO inhibitor, and dextromethorphan plus MAOIs can occasionally trigger serotonin-related reactions. Keep in mind this is theoretical, based on lab work rather than people. Still, I'd run it past your pharmacist or doctor before combining them.
- Zhao, T., He, Y. Q., Wang, J., Ding, K. M., Wang, C. H., and Wang, Z. T. Inhibition of human cytochrome P450 enzymes 3A4 and 2D6 by β-carboline alkaloids, harmine derivatives. Phytother Res 2011;25(11):1671-1677.
HEPATOTOXIC DRUGS
3 of 5Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine also falls under HEPATOTOXIC DRUGS.
Cases of hepatotoxicity and hepatic failure have been reported in patients who ingested a large quantity (up to 100 grams) of Syrian rue seeds.
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.
Here's the thing about this combo product (Theracaps): it contains acetaminophen, the same active ingredient as Tylenol. Acetaminophen is well known for being hard on the liver if you take too much of it. Syrian Rue, in large amounts, has its own track record of causing liver injury (real cases have been reported after people ate very large quantities of the seeds). So the worry here is that two liver stressors at once could add up.
This concern is theoretical and tied to big doses of Syrian Rue, not tiny amounts. Still, watch for warning signs like belly pain, yellowing skin or eyes, dark urine, or unusual tiredness. There's also a separate caution: Syrian Rue acts like an MAO inhibitor, and the dextromethorphan in this product can interact badly with MAOIs. Please run this by your pharmacist or doctor first.
- Yuruktumen, A., Karaduman, S., Bengi, F., and Fowler, J. Syrian rue tea: a recipe for disaster. Clin Toxicol (Phila) 2008;46(8):749-752. PubMed
- Berdai MA, Labib S, Harandou M. Peganum harmala L. Intoxication in a Pregnant Woman. Case Rep Emerg Med 2014;2014:783236.
- Ghizlane EA, Manal M, Ines HA, et al. Fatal poisoning of pregnant women by peganum harmala L.: a case reports. Ann Med Surg (Lond) 2021;68:102649. PubMed
- Durmaz Çelik N, Ger Akarsu F, Ozkan S, Özdemir AÖ, Aykac Ö, Memmedova F. Herbal teas can be harmful: a case of Peganum harmala induced coma in a patient with Parkinson's disease. Neurocase 2021;27(2):117-119.
CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES
4 of 5Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine also falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES.
Syrian rue contains beta-carboline alkaloids, including harmine, harmol, and harmane. In vitro research suggests that these beta-carboline alkaloids competitively inhibit CYP3A4 enzymes.
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.
This cold-and-cough combo (Theracaps) blends acetaminophen, dextromethorphan, phenylpropanolamine, and pyrilamine. The piece that matters most here is the dextromethorphan, the cough suppressant. Lab studies suggest Syrian Rue may slow down a liver enzyme (CYP3A4) that helps clear it. On paper, that could let dextromethorphan build up, possibly bringing on dizziness, drowsiness, confusion, or a restless, jittery feeling.
There's an extra wrinkle: Syrian Rue acts like an MAO inhibitor, and mixing MAO inhibitors with dextromethorphan can trigger a dangerous serotonin reaction. Even though this CYP3A4 concern is only theoretical, the combination as a whole is one I'd steer clear of. Please check with your pharmacist or doctor before taking these together.
- Zhao, T., He, Y. Q., Wang, J., Ding, K. M., Wang, C. H., and Wang, Z. T. Inhibition of human cytochrome P450 enzymes 3A4 and 2D6 by β-carboline alkaloids, harmine derivatives. Phytother Res 2011;25(11):1671-1677.
ANTICHOLINERGIC DRUGS
5 of 5Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine also falls under ANTICHOLINERGIC DRUGS.
Syrian rue contains harmine. Animal research suggests that intravenous administration of harmine potentiates the effects of acetylcholine or increases acetylcholine levels.
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.
This combination cold and cough product (Theracaps) includes pyrilamine, an antihistamine that works in part by quieting the brain chemical acetylcholine. That's what gives the drying, anticholinergic effect you may notice as dry mouth, drowsiness, or thickened mucus. The concern with Syrian Rue is the opposite direction: harmine, one of its main compounds, may raise acetylcholine activity, which could blunt the antihistamine's drying action.
Honestly, this is a theoretical worry drawn from animal studies, not solid human evidence, so I wouldn't lose sleep over it. The bigger issue is that Syrian Rue acts as an MAO inhibitor, and the dextromethorphan and phenylpropanolamine here can interact dangerously with MAO inhibitors. Please run this by your pharmacist or doctor before mixing them.
- Slotkin, T. A. and DiStefano, V. Cardiovascular and respiratory effects of harmine. Proc Soc Exp Biol Med 1970;133(2):662-664. PubMed
- Javoy, F., Euvrard, C., Herbet, A., Bockaert, J., Enjalbert, A., Agid, Y., and Glowinski, J. Lack of involvement of dopaminergic and GABA neurones in the inhbitory effect of harmaline on the activity of striatal cholinergic neurones in the rat. Naunyn Sch
What These Ratings Mean
Every interaction above is graded three ways — here’s the key to each label.
Clinically significant. Avoid the combination, or use only under close professional supervision.
Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.
Generally not serious. Be aware of it and mention it to your pharmacist.
- 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.
- 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.
Syrian Rue Also Interacts With Other Medications
Syrian Rue has 1,123 moderate known drug interactions in our database — the Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine one above is among them. If you take anything else, check it against the full list below.
Check Another of Your Medications Against Syrian Rue
We haven’t checked that one against Syrian Rue yet — ask our pharmacists directly.
Covers the 2,830 medications we’ve checked against Syrian Rue. Pick one to open its full report.
See Every Supplement That Interacts With Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine
This page covers Syrian Rue only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine page lists 282 supplements it has a documented interaction with, worst first, each one explained.
The most serious there right now: Activated Charcoal (major), Asarabacca (major), Beer (major), Ephedra (major) and Grapefruit (major).
By severity: 14 major · 223 moderate · 45 minor.
From our pharmacist’s overview on the Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine page
“Of everything on this page, ephedra worries me most for anyone using Theracaps (acetaminophen, dextromethorphan, phenylpropanolamine, and pyrilamine), because the decongestant in this cold formula is itself a stimulant. Adding ephedra or any of the 44 stimulant entries can push blood pressure and heart rate to unsafe levels.”
Reviewed by 2 · Jul 18, 2026
Open the Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine interaction page
Where Syrian Rue and Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine 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.
#947 of 1,452 supplements looked up here in the last 7 days
#226 of 2,830 medications looked up here in the last 7 days
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.
About Syrian Rue
What is Syrian Rue?
- Traditional remedy for digestive complaints
- Used as a sedative or for mood
- Antimicrobial and antiparasitic folk use
- Used as a dye and incense
- Recreational psychoactive use
Syrian Rue (Peganum harmala) is a traditional plant whose seeds contain potent compounds called harmala alkaloids, including MAO-inhibiting harmine and harmaline. There is little reliable human evidence that it safely treats any condition, and it carries real risks of toxicity, so it is not recommended for self-treatment. Talk to a pharmacist or doctor before considering it.
Other Drugs & Syrian Rue
Browse every other medication we’ve checked against Syrian Rue — both the ones with a known interaction and the ones without. Select any drug for the full detail.
No drugs match “”.
1,123 interactions
- Diclofenac Sodium ›
- Diltiazem ›
- Nifedipine ›
- Diphenhydramine ›
- Hydrocortisone ›
- Methylphenidate ›
- Doxycycline ›
- Erythromycin ›
- Estradiol ›
- Minocycline ›
- Propranolol ›
- Tetracycline ›
- Lidocaine ›
- Amoxicillin ›
- Norethindrone ›
- Testosterone ›
- Verapamil ›
- Fenofibrate ›
- Levonorgestrel ›
- Prednisone ›
- Quinidine ›
- Cyclosporine ›
- Dexamethasone ›
- Glyburide ›
- Glycopyrrolate ›
- Methyltestosterone ›
- Triazolam ›
- Zopiclone ›
- Ciprofloxacin ›
- Colchicine ›
- Fentanyl ›
- Oxybutynin ›
- Oxycodone ›
- Phenytoin ›
- Prednisolone ›
- Tacrolimus ›
- Temazepam ›
- Allopurinol ›
- Apomorphine ›
- Budesonide ›
- Carbamazepine ›
- Clindamycin ›
- Dextromethorphan ›
- Diclofenac Potassium ›
- Doxorubicin ›
- Fluticasone ›
- Formoterol ›
- Ipratropium ›
- Miconazole ›
- Morphine Sulfate ›
- Phenylephrine ›
- Procainamide ›
- Trimipramine ›
- Acetaminophen ›
- Amphetamine ›
- Buprenorphine ›
- Conjugated Estrogens ›
- Diazepam ›
- Dimenhydrinate ›
- Everolimus ›
Showing 60 of 1,123 moderate interactions — see all 1,123 on the Syrian Rue page.
No interaction 1,706 drugs checked — show the list
We also checked Syrian Rue against these medications and found no known interaction in our sources. Open any page to confirm.
- Levothyroxine ›
- Ivermectin ›
- Aspirin ›
- Levothyroxine, Liothyronine ›
- Ibuprofen ›
- Tirzepatide ›
- Isotretinoin ›
- Metformin ›
- Docusate ›
- Semaglutide ›
- Lisinopril ›
- Valacyclovir ›
- Hydroxyurea ›
- Bupropion ›
- Azithromycin ›
- Pregabalin ›
- Gabapentin ›
- Naproxen ›
- Lamotrigine ›
- Acyclovir ›
- Bendamustine ›
- Candesartan Cilexetil ›
- Aluminum Hydroxide, Aspirin, Magnesium Hydroxide ›
- Acetylsalicylic Acid ›
- Insulin Degludec, Liraglutide ›
- Calcium Oxybate, Magnesium Oxybate, Potassium Oxybate, Sodium Oxybate ›
- Aminophylline, Amobarbital, Ephedrine ›
- Aspirin, Butalbital ›
- Atenolol, Chlorthalidone ›
- Enalapril Maleate ›
- Bismuth Subcarbonate, Calcium Carbonate, Opium ›
- Ezetimibe ›
- Bendroflumethiazide, Rauwolfia Serpentina ›
- Cephalexin ›
- Aspirin, Ethoheptazine, Meprobamate ›
- Ephedrine, Phenobarbital, Theophylline ›
- Sacubitril, Valsartan ›
- Canagliflozin, Metformin ›
- Insulin Aspart, Insulin Degludec ›
- Levetiracetam ›
- Candesartan Cilexetil, Hydrochlorothiazide ›
- Atenolol ›
- Saxagliptin, Metformin Xr ›
- Hydrocortisone, Clioquinol, Pramoxine ›
- Sodium Bicarbonate (otc Drug) ›
- Cyclopentolate ›
- Efgartigimod Alfa-fcab ›
- Cytomegalovirus Immune Globulin ›
- Famotidine, Ibuprofen ›
- Ceftolozane Sulfate, Tazobactam Sodium ›
- Amobarbital, Ephedrine Sulfate ›
- Fosinopril, Hydrochlorothiazide ›
- Measles, Mumps, Rubella Virus Live ›
- Thyroid Hormone ›
- Alginic Acid, Aluminum Hydroxide ›
- Aminolevulinic Acid Hydrochloride ›
- Vestronidase Alfa-vjbk ›
- Glycerol Phenylbutyrate ›
- Mannitol ›
- Bupivacaine, Meloxicam ›
Showing the 60 most looked-up of 1,706 medications checked with no known interaction — see the full Syrian Rue list.
Sources & How We Checked
Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.
- Natural Medicines (Therapeutic Research Center) — Evidence-graded clinical reference for vitamins, herbs and supplements — the basis for our interaction data.
- MedlinePlus, U.S. National Library of Medicine — NIH consumer drug information, used for the medication overviews.
- NIH Dietary Supplement Label Database (DSLD) — Official supplement product labels.
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
Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine Is Linked to Lower Levels of One Nutrient
Natural Medicines records Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine as a medicine that can lower these. This is not an interaction with Syrian Rue — it is a separate effect of the medicine, and it is a reason some people are advised to supplement rather than to avoid one:
Depletion records come from the licensed Natural Medicines database. Do not start a supplement on the strength of this page — ask your pharmacist or doctor whether it applies to you.
Taking Syrian Rue and Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine Together: Common Questions
Can you take Syrian Rue with Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine?
Why are there 5 interactions listed for Syrian Rue and Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine?
How serious is the Syrian Rue and Acetaminophen, Dextromethorphan, Phenylpropanolamine, Pyrilamine interaction?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
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