Cabergoline is a dopamine agonist medication that mimics the action of the neurotransmitter dopamine. Its primary medical purpose is to treat hyperprolactinemia, a condition characterized by high levels of the hormone prolactin, often caused by a prolactin-secreting pituitary tumor. While effective in lowering prolactin and shrinking these tumors, the drug has a range of potential side effects. Hair loss is a documented adverse event that concerns people starting this treatment.
The Connection Between Cabergoline and Hair Loss
Cabergoline is listed in post-marketing surveillance reports as a cause of hair loss, or alopecia. The frequency of this side effect is generally considered rare, with its incidence often categorized as “not known” because it was not commonly observed during initial controlled clinical trials. Despite its rarity, confirmed case reports suggest a causal link between the medication and experiencing hair thinning.
The hair loss is typically a reversible, non-scarring form of diffuse shedding known as telogen effluvium. This condition occurs when a stressor, such as a medication or hormonal shift, prematurely forces hair follicles into the resting (telogen) phase of the hair cycle. Because cabergoline suppresses prolactin, this systemic effect is thought to disrupt the normal, cyclical growth pattern of the hair. Hair loss has been reported with various dopaminergic drugs, suggesting it may be a class effect, although the precise physiological mechanism remains unclear.
Immediate Actions After Noticing Hair Thinning
Upon noticing increased hair shedding, immediately contact the prescribing physician, which is typically an endocrinologist. Do not stop taking cabergoline abruptly, as discontinuing the medication without medical guidance can lead to a rebound in prolactin levels and tumor growth. The physician will need to determine if the medication is truly the cause of the hair thinning.
Accurate diagnosis requires a medical history, including the timeline of when the hair loss began in relation to starting cabergoline or changing its dosage. Physicians must also rule out other common, non-drug-related causes of diffuse hair loss, which can present similarly to medication-induced alopecia. Blood tests are necessary to check for underlying conditions such as thyroid dysfunction, iron or ferritin deficiency, and vitamin imbalances, as these are frequent contributors to hair shedding. A physical examination, including a hair pull test, may also be performed to assess the severity of active shedding.
Treatment and Management Strategies
Once the medical team determines that cabergoline is the most likely cause of the hair loss, management focuses on minimizing the side effect while maintaining control over the underlying condition. The initial strategy often involves attempting a dosage adjustment, as reducing the cabergoline dose can sometimes stabilize the hair cycle and lead to regrowth. All changes to the dose must be performed under medical supervision to ensure prolactin levels remain within a safe range.
If dose reduction is not feasible because it compromises the control of hyperprolactinemia, the physician may consider switching to an alternative dopamine agonist, such as bromocriptine. Patients should be aware that hair loss is a potential side effect of the entire drug class, and cross-reactivity is possible.
For patients whose primary condition is stable, supportive care can be implemented, including optimizing nutrition and treating any identified deficiencies, such as low ferritin or Vitamin D. Topical treatments, such as minoxidil, may be recommended by a dermatologist to stimulate hair follicle activity and encourage faster regrowth. Hair loss caused by medication is generally reversible once the trigger is removed or adjusted, though it can take anywhere from three to eighteen months for the hair to return to its original density.