Drug Interaction Report

Black Currant and Anagrelide: Interaction Details

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Anagrelide

Agrylin Agrylin®
+

Black Currant

No brand names on record
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Updated Aug 8, 2026
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Interaction severity
Moderate
Can be significant — usually manageable with monitoring.
How we grade severity & evidence

Severity levels

  • Contraindicated: These should generally not be used together.
  • Major: Potentially serious — often needs a change or close monitoring.
  • Moderate: Can be significant — usually manageable with monitoring.
  • Minor: Usually limited clinical impact.

Evidence grades

  • Established: Well documented — supported by controlled studies or strong clinical data.
  • Probable: Good supporting evidence, though not definitively proven.
  • Suspected: Some evidence suggests this interaction, but it is not well established.
  • Possible: Limited or conflicting evidence; the interaction may occur.
  • Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.

Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.

Of 16 documented Black Currant interactions, 16 are rated moderate — including this one.
Onset
delayed
Evidence
theoretical
Severity
Moderate

What happens

Increased risk of bleeding

Interaction Deep Dive

Theoretically, taking black currant and antiplatelet agents may increase the risk of bleeding. Black currant seed oil is rich in gamma-linolenic and alpha-linoleic acids3, similar to evening primrose oil. Evening primrose oil inhibited platelet aggregation and prolonged bleeding time in humans 2. Gamma-linolenic acid from evening primrose oil inhibited thromboxane B2 production and increased prostacyclin production 2. Caution is advised if black currant is taken with antiplatelet agents 1.

Why it happens (mechanism)

Additive antiplatelet effects

Literature reports

1 report — tap to read

a) Evening primrose oil (EPO) significantly reduced platelet aggregation and prolonged bleeding time in a randomized, blinded, crossover study of 12 males. Patients received EPO 3 grams daily (providing 2200 milligrams (mg) linoleic acid and 240 mg gamma-linolenic acid) for 4 months. Antiplatelet drugs were discontinued at least 8 weeks before the study. Adenosine diphosphate, adrenaline, and collagen-induced platelet aggregation were significantly reduced compared to placebo after 2 and 4 months of EPO supplementation. Platelet production of thromboxane B2 was significantly decreased from baseline (p less than 0.001) at 3 and 4 months of EPO treatment. Bleeding time increased 40% over baseline after 3 and 4 months of EPO treatment (p less than 0.001) 2.

Common questions

Can I take Black Currant and Anagrelide together?

Increased risk of bleeding Always confirm with your pharmacist or prescriber before making any change.

How serious is the Black Currant and Anagrelide interaction?

It is rated moderate. Can be significant — usually manageable with monitoring.

How quickly could this interaction happen?

The documented onset is "delayed". Effects tend to build up gradually over days to weeks.

How strong is the evidence for this interaction?

The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.

From our Q&A

Real reader questions about these medications, each personally answered by our pharmacist:

Questions for your pharmacist

  • Does my dose of Black Currant or Anagrelide need adjusting while I take them together?
  • What symptoms should prompt me to call you or my prescriber right away?
  • Does the timing of my doses matter for this combination?
  • Is there anything you'd monitor while I'm on both?

References (3)

  1. Norred CL & Brinker F: Potential coagulation effects of preoperative complementary and alternative medicines. Alt Ther 2001; 7(6):58-67.
  2. Guivernau M, Meza M, Barja P, et al: Clinical and experimental study on the long-term effect of dietary gamma-linolenic acid on plasma lipids, platelet aggregation, thromboxane formation, and prostacyclin production. Prostaglandin Leukot Essent Fatty Acids 1994; 51:311-316. PubMed
  3. Wu D, Meydani M, Leka LS et al: Effect of black currant seed oil (BCSO) supplementation on immune response of healthy elderly subjects (abstract 5035). Presented at Experimental Biology 98; San Francisco, CA, April 18-22, 1998.
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Beyond drug–drug

These medications also interact with supplements

Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:

major · moderate · minor — check everything you take with our drug–supplement interaction checker.

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This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.