Black Seed - Sulfamethoxazole Interaction
Herbal: Black Seed
Also Known As: Nigella sativa, black caraway, black cumin, Roman-Coriander, Ajenuz, Aranuel, Baraka, Black Caraway, Black Cumin, Black Cumin Seed Oil, Charnuska, Cheveux de Vénus, Cominho Negro, Comino Negro, Cumin Noir, Cyah Dane, Fennel Flower, Fitch, Graine de Nigelle, Graine Noire, Hab
Drug: Sulfamethoxazole
Brand names:
Gantanol
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
May 04, 2025
Interaction Details
Sulfamethoxazole is classified as belonging to the following category: Cytochrome P450 2C9 (Cyp2C9) Substrates
Theoretically, black seed might increase levels of drugs metabolized by CYP2C9.
In vitro research suggests that thymoquinone, a constituent of black seed, can decrease the metabolism of phenytoin by a mechanism possibly related to the inhibition of CYP2C9. The effect of black seed on CYP2C9 is unclear. This has not been shown in humans.
Interaction Rating
Likelihood of Occurrence
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
References
- Wang Z, Wang X, Wang Z, et al. Potential herb-drug interaction risk of thymoquinone and phenytoin. Chem Biol Interact. 2022;353:109801.
Black Seed Overview
Black seed, also known as black cumin, is a flowering plant belonging to the Ranunculaceae family. It is used in traditional medicine for the treatment of several conditions, including bronchitis, colic, fatigue, fever, headache, toothache, back pain, and infections. Most dietary supplements containing black seed market it as supporting the respiratory and digestive system, as well as improving immune health. Black seed oil is obtained from the seeds being cold-pressed.
In regard to supplements, whole black seeds contain both the oil and other components such as fiber and proteins, while black seed oil is a concentrated source of the oil only. Both can be taken as supplements, but black seed oil contains larger amounts of active components, while whole seeds can provide additional nutrients and fiber.
Black Seed - More Interactions
Black Seed interacts with 894 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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Dr. Brian Staiger, PharmD
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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