Melatonin - Welireg (Belzutifan) Interaction
Herbal: Melatonin
Also Known As: N-Acetyl-5-Methoxytryptamine
Drug: Belzutifan
Brand names:
Welireg
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
May 04, 2025
Interaction Details
Belzutifan is classified as belonging to the following category: Cytochrome P450 2C19 (Cyp2C19) Substrates
Theoretically, melatonin might increase levels of drugs metabolized by CYP2C19. Also, other CYP2C19 substrates might decrease the metabolism of melatonin, increasing melatonin levels.
Melatonin is metabolized in the liver primarily by the CYP2C19 and CYP1A2 enzymes. Theoretically, combined administration of melatonin with certain drugs metabolized by the CYP2C19 enzyme may reduce the metabolism of these drugs, resulting in increased serum levels. Conversely, some drugs metabolized by CYP2C19 may inhibit the metabolism of melatonin, resulting in increased serum levels of melatonin. Until more is known, use melatonin cautiously in patients taking drugs metabolized by these enzymes.
Interaction Rating
Likelihood of Occurrence
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.
References
- Yeleswaram, K., Vachharajani, N., and Santone, K. Involvement of cytochrome P-450 isozymes in melatonin metabolism and clinical implications. J Pineal Res 1999;26(3):190-191.
- Faber, M. S., Jetter, A., and Fuhr, U. Assessment of CYP1A2 activity in clinical practice: why, how, and when? Basic Clin Pharmacol Toxicol. 2005;97(3):125-134.
Melatonin Overview
Melatonin is a hormone that is produced naturally in the pineal gland. It is involved in several different bodily processes, such as the regulation of the body's sleep-wake cycle.
Melatonin is available as a dietary supplement and is often used to help people with sleep disorders, such as insomnia, fall asleep more easily.
There is some evidence to suggest that melatonin supplements may be helpful in reducing the time it takes to fall asleep and improving sleep quality, although the results of studies on this topic have been mixed. Studies show better support for some specific conditions, such as Delayed sleep phase syndrome (DSPS) and Non-24-hour sleep-wake disorder.
Melatonin is generally considered to be safe when used in the short term, although it can cause side effects in some people, such as dizziness, headache, and nausea.
While melatonin is a natural hormone, it is often synthesized for its use in dietary supplements.
Belzutifan Overview
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Belzutifan is used in adults with von Hippel-Lindau disease (VHL; a rare disease that causes tumors and cysts) to treat renal cell carcinoma (RCC; kidney cancer), central nervous system (CNS) hemangioblastomas (tumors in the brain and spinal cord), and a certain type of pancreatic cancer that does not require surgery right away. Belzutifan is in a class of medications called hypoxia-inducible factor inhibitors. It works by blocking the activity of a certain protein in people with VHL.
Melatonin - More Interactions
Melatonin interacts with 1425 drugs
Interaction Rating Key
These severity listings are for informational use only. Never start, stop or otherwise change your therapy before speaking with your provider.
| Major | The combined use of these agents is strongly discouraged as serious side effects or other negative outcomes could occur. |
| Moderate | Use cautiously under the care of a healthcare professional or avoid this combination. A significant interaction or negative outcome could occur. |
| Minor | Be aware that there is a chance of an interaction. Watch for warning signs of a potential interaction. |
| Unknown | No interactions have been reported or no interaction data is currently available. |
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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
Drug descriptions are provided by MedlinePlus.
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In addition to being a clinical pharmacist specializing in pharmacotherapy, Dr. Brian Staiger is a registered herbalist through the American Herbalist Guild. He has combined his passion for pharmacy practice with the study of medical ethnobotany to improve patient care. Feel free to reach out about any of your herbal or medication questions!
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