Oral tretinoin (all-trans retinoic acid, ATRA) is a retinoid that induces differentiation of immature promyelocytes into mature granulocytes. It is the cornerstone of treatment for acute promyelocytic leukemia (APL) and has revolutionized outcomes for this subtype of leukemia, transforming it from one of the most fatal to the most curable form of acute leukemia when combined with arsenic trioxide. It is not commonly used for dermatologic conditions (topical tretinoin is used for acne and photoaging instead).
Known hypersensitivity to tretinoin or retinoids1,2
The bottom line
Evidence rating strong. Most-documented uses: induces complete remission in apl (up to 90% when combined with arsenic trioxide), targeted differentiation therapy, transforms cancer cells into normal cells, transformed apl from fatal to highly curable disease. 10 sources indexed (2019–2025), with 1 interaction record on file.
The science
How it works, mechanistically.
Core mechanism
Binds to retinoic acid receptors (RAR-alpha) in the nucleus, restoring normal gene transcription in promyelocytic leukemia cells. In APL, the PML-RARA fusion protein blocks myeloid differentiation; oral tretinoin degrades this fusion protein, releasing the differentiation block and allowing leukemic promyelocytes to mature into functional granulocytes. This is a targeted differentiation therapy rather than cytotoxic chemotherapy.4,7
Class
Retinoid / Dermatologic-Oncologic
Absorption
Fat-soluble; take with food
Dosing
Dosing & protocol.
Common range
45 mg/m²/day divided into two equal doses until complete remission or 90 days (as prescribed by your physician)
Recommended form
Oral capsule
Fat-soluble; take with food to enhance absorption. Peak plasma levels in 1-2 hours. Subject to autoinduction of metabolism with continuous use.
Oral tretinoin is all-trans retinoic acid, an active vitamin A metabolite used systemically for acute promyelocytic leukemia. Adding preformed vitamin A supplements can intensify retinoid toxicity, including headache, mucocutaneous toxicity, liver abnormalities, lipid changes, and teratogenic risk. This is not a timing problem because both exposures converge on systemic retinoid signaling.
Recommendation: Do not take vitamin A supplements, cod liver oil, or high-retinol multivitamins during oral tretinoin therapy unless your oncology team explicitly prescribes them. Bring all supplements to medication reconciliation. Report severe headache, vision changes, abdominal pain, jaundice, or pregnancy exposure immediately.
Chean D, Kemp H, Fodil S et al.. Early mortality in patients with acute promyelocytic leukemia: a systematic review and meta-analysis. Critical care (London, England). 2025
Langdon K, Cosentino S, Wawryk O. Superiority of anthracycline-free treatment in standard-risk acute promyelocytic leukemia: A systematic review and comparative epidemiological analysis. Cancer reports (Hoboken, N.J.). 2024
Mohty R, Reljic T, Yassine F et al.. Efficacy of Autologous and Allogeneic Hematopoietic Cell Transplantation in Adults with Acute Promyelocytic Leukemia: Results of a Systematic Review and Meta-Analysis. Transplantation and cellular therapy. 2024
Yang J, Zhao L, Wang W et al.. All-trans retinoic acid added to treatment of primary immune thrombocytopenia: a systematic review and meta-analysis. Annals of hematology. 2023
Mohammadi Kanesbi M, Jarahi L, Keramati MR. Blood Parameters in Treatment with Arsenic Trioxide in Acute Promyelocytic Leukemia: A Systematic Review. International journal of hematology-oncology and stem cell research. 2020
Lima L, de Melo TCT, Marques D et al.. Modulation of all-trans retinoic acid-induced MiRNA expression in neoplastic cell lines: a systematic review. BMC cancer. 2019
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