Drug & supplement interaction

Phenylalanine + Bendamustine

Bendamustine brand names: Treanda, Belrapzo, Vivimusta.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 13, 2026
The bottom line No known interaction

We found no known interaction between Phenylalanine and Bendamustine 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

Phenylalanine and Bendamustine

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 Bendamustine and Phenylalanine 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.

Phenylalanine safety at a glance

Phenylalanine overall Use caution Generally tolerated in food amounts, but supplements should be used carefully and not by people with PKU.
Pregnancy Likely Safe When L-phenylalanine is consumed in amounts typically found in foods by pregnant patients with normal phenylalanine metabolism. Read the full pregnancy detail
Breastfeeding Likely Safe When L-phenylalanine is consumed in amounts typically found in foods by breast-feeding patients with normal phenylalanine metabolism. There is insufficient reli... Read the full breastfeeding detail

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 Bendamustine and Phenylalanine? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Bendamustine

Interactions in our licensed database are recorded against drug classes, not just single drug names. Bendamustine is filed under 4 classifications — including alkylating agents, antineoplastics, cytochrome p450 1a2 (cyp1a2) substrates. Phenylalanine has documented interactions with 3 drug classes — the most serious being levodopa (major), baclofen (moderate) and monoamine oxidase inhibitors (maois) (moderate) — and none of Bendamustine’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

Phenylalanine Does Interact With Other Medications

Phenylalanine has 5 major, 11 moderate known drug interactions in our database — Bendamustine isn’t one of them. If you take anything else, check it against the full list below.

Major 5 Moderate 11 No known interaction 2,814 (incl. Bendamustine)
Taking anything else?

Check Another of Your Medications Against Phenylalanine

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

What to actually watch for

What Phenylalanine Itself Has Been Linked To

This is not an interaction — nothing below involves Bendamustine. It is the side-effect record for Phenylalanine on its own, from the licensed Natural Medicines monograph. If something new turns up after you add Phenylalanine, this list is the first place to look. One entry is worth acting on rather than waiting out — marked below.

  • Mania or an unusually elevated mood Worth acting on Additional detail

    “Orally, L-phenylalanine has been associated with anxiety, insomnia, and, more rarely, hypomania. DL-phenylalanine has been associated with fatigue and sedation.”

    Phenylalanine · Natural Medicines adverse-effect record, reported in anxiety.

    3 sources cited
    1. 68827. Sabelli, H. C., Fawcett, J., Gusovsky, F., Javaid, J. I., Wynn, P., Edwards, J., Jeffriess, H., and Kravitz, H. Clinical studies on the phenylethylamine hypothesis of affective disorder: urine and blood phenylacetic acid and phenylalanine dietary supplem
    2. 68829. Kravitz, H. M., Sabelli, H. C., and Fawcett, J. Dietary supplements of phenylalanine and other amino acid precursors of brain neuroamines in the treatment of depressive disorders. J Am Osteopath.Assoc 1984;84(1 Suppl):119-123. DOI
    3. 9951. Wood DR, Reimherr FW, Wender PH. Treatment of attention deficit disorder with DL-phenylalanine. Psychiatry Res 1985;16:21-6.. PubMed
  • Heartburn / Constipation Additional detail

    “Orally, constipation, heartburn, and nausea has been reported in some patients taking phenylalanine.”

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

    4 sources cited
    1. 2463. Siddiqui AH, Stolk LM, Bhaggoe R, et al. L-phenylalanine and UVA irradiation in the treatment of vitiligo. Dermatology 1994;88:215-8. PubMed
    2. 68827. Sabelli, H. C., Fawcett, J., Gusovsky, F., Javaid, J. I., Wynn, P., Edwards, J., Jeffriess, H., and Kravitz, H. Clinical studies on the phenylethylamine hypothesis of affective disorder: urine and blood phenylacetic acid and phenylalanine dietary supplem
    3. 68829. Kravitz, H. M., Sabelli, H. C., and Fawcett, J. Dietary supplements of phenylalanine and other amino acid precursors of brain neuroamines in the treatment of depressive disorders. J Am Osteopath.Assoc 1984;84(1 Suppl):119-123. DOI
    4. 68830. Mann, J., Peselow, E. D., Snyderman, S., and Gershon, S. D-phenylalanine in endogenous depression. Am.J.Psychiatry 1980;137(12):1611-1612. PubMed
  • Tremor or shakiness / Dizziness Additional detail

    “Orally, headaches, which are typically transient and do not require treatment or dosage reduction, have been reported during the first 10 days of treatment with L-, D-, and DL-phenylalanine. Transient vertigo has also been reported with D- and DL-phenylalanine.

    In patients with Parkinson disease, taking DL-phenylalanine, especially in high doses, interferes with levodopa transport into the brain, causing increased ri…”

    Phenylalanine · Natural Medicines adverse-effect record, reported in myasthenia gravis.

    6 sources cited
    1. 68795. Fischer, E., Heller, B., Nachon, M., and Spatz, H. Therapy of depression by phenylalanine. Preliminary note. Arzneimittelforschung. 1975;25(1):132.
    2. 68825. Beckmann, H., Strauss, M. A., and Ludolph, E. Dl-phenylalanine in depressed patients: an open study. J.Neural Transm. 1977;41(2-3):123-134. PubMed
    3. 68827. Sabelli, H. C., Fawcett, J., Gusovsky, F., Javaid, J. I., Wynn, P., Edwards, J., Jeffriess, H., and Kravitz, H. Clinical studies on the phenylethylamine hypothesis of affective disorder: urine and blood phenylacetic acid and phenylalanine dietary supplem
    4. 68829. Kravitz, H. M., Sabelli, H. C., and Fawcett, J. Dietary supplements of phenylalanine and other amino acid precursors of brain neuroamines in the treatment of depressive disorders. J Am Osteopath.Assoc 1984;84(1 Suppl):119-123. DOI
    5. 3291. Nutt JG, Woodward WR, Hammerstad JP, et al. The "on-off" phenomenon in Parkinson's disease. Relation to levodopa absorption and transport. N Engl J Med 1984;310:483-8. PubMed
    6. 3292. Baruzzi A, Contin M, Riva R, et al. Influence of meal ingestion time on pharmacokinetics of orally administered levodopa in parkinsonian patients. Clin Neuropharmacol 1987;10:527-37. PubMed
  • Drowsiness / Anxiety or restlessness / Trouble sleeping Additional detail

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

  • Itching Additional detail

    “Topically, erythema, itching, and burning have been reported in some patients using an undecylenoyl phenylalanine 2% cream for treatment of age spots.”

    Phenylalanine · Natural Medicines adverse-effect record, reported in erythema.

    1 source cited
    1. 92704. Katoulis AC, Alevizou A, Bozi E, et al. A randomized, double-blind, vehicle-controlled study of a preparation containing undecylenoyl phenylalanine 2% in the treatment of solar lentigines. Clin Exp Dermatol 2010;35(5):473-6. PubMed
  • Tiredness Additional detail

    Recorded for Phenylalanine in the same Natural Medicines adverse-effect record shown under Mania or an unusually elevated mood above.

Showing the 10 most notable of 12 recorded effects — ranked by how unusual each one is across medicines generally, with serious effects weighted up.

Everything above comes from the Natural Medicines adverse-effect record for Phenylalanine — expand a row for the licensed statement it rests on. We haven’t matched Bendamustine to its FDA label in our system yet, so we can’t compare its own side-effect list here — the leaflet that comes with your prescription is the authoritative list for Bendamustine.

Special populations

Phenylalanine in Pregnancy & Breastfeeding

Pregnancy Likely Safe

When L-phenylalanine is consumed in amounts typically found in foods by pregnant patients with normal phenylalanine metabolism.

Pregnancy Unsafe

When L-phenylalanine is consumed in amounts typically found in foods by pregnant patients with high serum phenylalanine concentrations, such as those with phenylketonuria (PKU). Serum levels of phenylalanine greater than 360 micromol/L increase the risk of birth defects. Experts recommend that patients with high phenylalanine serum concentrations follow a low phenylalanine diet for at least 20 weeks prior to conception to decrease the risk for birth defects. There is insufficient reliable information available about the safety of L-phenylalanine when taken by mouth in large doses during pregnancy; avoid using. There is insufficient reliable information available about the safety of oral D-phenylalanine during pregnancy; avoid using.

Lactation Likely Safe

When L-phenylalanine is consumed in amounts typically found in foods by breast-feeding patients with normal phenylalanine metabolism. There is insufficient reliable information available about the safety of L-phenylalanine when taken by mouth in medicinal amounts during lactation; avoid using. There is insufficient reliable information available about the safety of oral D-phenylalanine during lactation; 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

Everything else you take

See Every Supplement That Interacts With Bendamustine

This page covers Phenylalanine only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Bendamustine page lists 87 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Acerola (moderate), Adrafinil (moderate), African Wild Potato (moderate), Alpha-lipoic Acid (moderate) and Ashitaba (moderate).

By severity: 62 moderate · 25 minor.

From our pharmacist’s overview on the Bendamustine page

“Bendamustine (Treanda, Belrapzo, Vivimusta) is IV chemotherapy for chronic lymphocytic leukemia and certain lymphomas, and the liver clears it through an enzyme called CYP1A2. That enzyme is why nearly all 87 supplements on this page appear here, since about 80 of them can push CYP1A2 up or down, which could either raise side effects o…”

Reviewed by 2 · Jul 18, 2026

Open the Bendamustine interaction page

One more smart check

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

We hold 1,990 real supplement products containing Phenylalanine, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Phenylalanine. Even though Phenylalanine itself has no known interaction with Bendamustine, 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 Phenylalanine and Bendamustine 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 Phenylalanine
Top 10%

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

29 days ago today
Medication Bendamustine
Top 5%

#56 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 Phenylalanine reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Phenylalanine and Bendamustine 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 Phenylalanine

What is Phenylalanine?

  • Depression and mood
  • Skin condition vitiligo
  • Pain conditions
  • Attention and focus
  • Appetite control

Phenylalanine is an essential amino acid the body uses to make brain chemicals like dopamine and norepinephrine. Some people take it for mood, vitiligo, or pain, but the evidence is mostly limited or mixed. People with the genetic condition PKU must strictly avoid it.

Amino acid (not a plant part) · Capsules, tablets, powder

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

Phenylalanine: dosing

There is no well-established standard supplement dose for phenylalanine, and the right amount may differ depending on the form (L-, D-, or DL-) and the reason for use.If you choose to use a product, follow the directions on the label and do not exceed the recommended amount.

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

Read the full Phenylalanine monograph & all interactions
Medication

About Bendamustine Injection

What Is Bendamustine Injection Used For?

Brand names: Treanda, Belrapzo, Vivimusta

Bendamustine hydrochloride injection is used to treat adults with chronic lymphocytic leukemia (CLL). It is also used for adults with indolent B-cell non-Hodgkin lymphoma (NHL) — a slow-growing type of blood cancer — when the disease has continued to progress during or within six months of treatment with rituximab or a rituximab-containing regimen.

For CLL, how well bendamustine works compared to other first-line treatments (aside from chlorambucil) has not been fully established.

See full Bendamustine Injection drug information
Keep checking

Other Drugs & Phenylalanine

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

5Major
11Moderate
0Minor
2,813No known interaction
5 Major 11 Moderate 2,813 No interaction
Major

5 interactions

Moderate

11 interactions

No interaction 2,813 drugs checked — show the list

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

Showing the 60 most looked-up of 2,813 medications checked with no known interaction — see the full Phenylalanine list.

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

Phenylalanine References

The 23 references that drive our Phenylalanine 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. Rouse B, Azen C, Koch R, et al. Maternal phenylketonuria collaborative Study (MPKUCS) offspring: facial anomalies, malformations, and early neurological sequelae. Am J Med Genet 1997;69:89-95. DOI
  2. Sturtevant FM. Use of aspartame in pregnancy. Int J Fertil 1985;30:85-7.
  3. Silkaitis RP, Mosnaim AD. Pathways linking L-phenylalanine and 2-phenylethylamine with p-tyramine in rabbit brain. Brain Res 1976;114:105-15.
  4. Lehmann WD, Theobald N, Fischer R, Heinrich HC. Stereospecificity of phenylalanine plasma kinetics and hydroxylation in man following oral application of a stable isotope-labelled pseudo-racemic mixture of L- and D-phenylalanine. Clin Chim Acta 1983;128 PubMed
  5. Mosnik DM, Spring B, Rogers K, Baruah S. Tardive dyskinesia exacerbated after ingestion of phenylalanine by schizophrenic patients. Neuropsychopharmacology 1997;16:136-46. PubMed
  6. Siddiqui AH, Stolk LM, Bhaggoe R, et al. L-phenylalanine and UVA irradiation in the treatment of vitiligo. Dermatology 1994;88:215-8. PubMed
  7. Birkmayer W, Riederer P, Linauer W, Knoll J. L-deprenyl plus L-phenylalanine in the treatment of depression. J Neural Transm 1984;59:81-7. PubMed
  8. Nutt JG, Woodward WR, Hammerstad JP, et al. The "on-off" phenomenon in Parkinson's disease. Relation to levodopa absorption and transport. N Engl J Med 1984;310:483-8. PubMed
  9. Baruzzi A, Contin M, Riva R, et al. Influence of meal ingestion time on pharmacokinetics of orally administered levodopa in parkinsonian patients. Clin Neuropharmacol 1987;10:527-37. PubMed
  10. Juncos JL, Fabbrini G, Mouradian MM, et al. Dietary influences on the antiparkinsonian response to levodopa. Arch Neurol 1987;44:1003-5. PubMed
  11. Eriksson T, Granerus AK, Linde A, et al. "On-off" phenomenon in Parkinson's disease: relationship between dopa and other large neutral amino acids in plasma. Neurology 1988;38:1245-8. PubMed
  12. Baker GB, Bornstein RA, Rouget AC, et al. Phenylethylaminergic mechanisms in attention-deficit disorder. Biol Psychiatry 1991;29:15-22.. PubMed
  13. Wood DR, Reimherr FW, Wender PH. Treatment of attention deficit disorder with DL-phenylalanine. Psychiatry Res 1985;16:21-6.. PubMed
  14. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). Washington, DC: National Academy Press, 2002. Available at: http://www.n
  15. Cederbaum S. Phenylketonuria: an update. Curr Opin Pediatr 2002;14:702-6. 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 Phenylalanine and Bendamustine Together: Common Questions

Is it safe to take Phenylalanine with Bendamustine?
We do not list a known interaction between Phenylalanine and Bendamustine. 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 Phenylalanine and Bendamustine combination checked?
Interactions in our licensed database are recorded against drug classes. Bendamustine is filed under 4 classifications, and Phenylalanine has documented interactions with 3 drug classes — none of Bendamustine'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 Phenylalanine interact with any other medications?
Yes. Phenylalanine has 16 documented drug interactions in our database — Bendamustine 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 Bendamustine interact with any supplements?
Yes. Bendamustine has documented interactions with 87 supplements in our database — Phenylalanine is not one of them. The Bendamustine 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

Phenylalanine monograph Uses, safety profile, and every drug interaction in one place Bendamustine Injection drug information The full plain-English guide to this medication Bendamustine supplement interactions Every supplement checked against Bendamustine, 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 23 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Bendamustine and Phenylalanine?

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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.