Encyclopedia · drug with hair side effects
CDK4/6 inhibitors (palbociclib, ribociclib, abemaciclib)
Breast-cancer pills that cause a thinning pattern similar to androgenetic alopecia, concentrated at the crown, with a slightly weaker response to minoxidil than with hormone therapy alone.
What it is
Prescription oral drugs combined with endocrine therapy in hormone-receptor-positive, HER2-negative breast cancer.
How it works
They arrest the cell cycle, and hair follicles are fast-cycling tissue. The authors of one cohort noted the pattern resembles androgenetic alopecia.
What the studies show
- A meta-analysis of randomized trials (2,007 patients) found a relative risk of all-grade alopecia of 2.14 (95% CI 1.23-3.73) versus placebo plus hormone therapy. Lasheen 2017
- In a 28-patient retrospective cohort, thinning at the vertex was found in 70.0% on a CDK4/6 inhibitor plus endocrine therapy versus 36.4% on endocrine therapy alone. Minoxidil gave moderate to significant improvement in 80% versus 94.4%. Small and uncontrolled. Minta 2023
- A review places alopecia among the non-specific skin effects of these drugs. Sibaud 2023
How it's used in studies
Low-dose oral or 5% topical minoxidil for 4-6 months in the cohort.
Side effects and safety
Not hair-specific; see oncology labels.
Bottom line
Hair loss on these drugs is real and partly treatable, but the minoxidil data are uncontrolled. Discuss with a doctor.
Fun facts
- A cancer drug that blocks cell division produced thinning concentrated at the crown, mimicking male-pattern baldness in women. Minta 2023
Studies 3
Lasheen S et al. Fatigue, alopecia and stomatitis in patients with breast cancer receiving CDK4/6 inhibitors: a meta-analysis. Expert Rev Anticancer Ther. 2017
Result: Relative risk of all-grade alopecia 2.14 (95% CI 1.23-3.73) vs placebo plus hormone therapy.
Read the study ↗Minta A et al. CDK4/6-inhibitor-induced alopecia in breast cancer patients. Support Care Cancer. 2023
Result: Vertex involvement 70.0% with CDK4/6 inhibitor plus endocrine therapy vs 36.4% with endocrine therapy alone; minoxidil improved 80% vs 94.4%.
Read the study ↗Sibaud V, Sollena P. Dermatologic toxicities to CDK4/6 inhibitors. Ann Dermatol Venereol. 2023
Result: Alopecia is among the non-specific skin effects of CDK4/6 inhibitors.
Read the study ↗Related
- Breast cancer endocrine therapy (tamoxifen, aromatase inhibitors)Anti-estrogen pills taken for years after breast cancer can cause female pattern-type thinning, and in one uncontrolled series topical minoxidil helped 80% of those assessed.
- MinoxidilThe most widely used hair-growth treatment, available as a cheap over-the-counter lotion or foam and as a prescription tablet, with a mechanism that is still only partly understood.
- Hedgehog pathway inhibitors (vismodegib, sonidegib)Skin-cancer pills that block the Hedgehog pathway, which drives follicle growth, caused hair loss in 56.9% of patients in a meta-analysis, the highest of any targeted cancer drug.