Metoprolol is a beta-blocker medication primarily prescribed to manage conditions like high blood pressure, angina (chest pain), and certain heart rhythm disorders. It works by blocking the effects of adrenaline on the heart, which slows the heart rate and relaxes blood vessels. Patients often pay close attention to potential side effects when starting long-term medication, including the possibility of hair loss. Understanding the drug’s connection to hair thinning requires looking closely at its reported effects and the underlying biology of hair growth.
Metoprolol as a Cause of Hair Thinning
Hair thinning is recognized as a possible side effect of Metoprolol, though it is classified as an uncommon or rare occurrence. During initial clinical trials, hair loss was not a commonly reported adverse event. Most reported instances come from post-market surveillance and voluntary patient reports submitted after the drug has been in wide use.
The frequency of this side effect is low, affecting less than one percent of users. Precise numbers are difficult to establish because voluntary reporting systems, such as the FDA Adverse Events Reporting System, cannot definitively prove the medication was the direct cause. Hair thinning has numerous causes, and other medical conditions or lifestyle factors may contribute to reported cases.
When hair loss is attributed to Metoprolol, the condition is typically reversible. Once the medication is discontinued, the normal hair growth cycle usually resumes, and hair regrowth is expected over several months. However, patients must never stop taking prescribed Metoprolol suddenly, as this can have serious consequences for heart health.
How Medications Affect the Hair Growth Cycle
The hair on the scalp cycles through three main phases: Anagen, Catagen, and Telogen. The Anagen phase is the growth phase, lasting several years and involving active cell division in the hair follicle. The Catagen phase is a short transition period lasting a few weeks where growth stops and the outer root sheath shrinks.
The final stage is the Telogen phase, or resting phase, which typically lasts two to four months before the hair is shed. Normally, about 90% of hair follicles are in the long Anagen phase, with only 5% to 15% in the resting Telogen phase at any given time.
Drug-induced hair loss, including that linked to Metoprolol, is often called Telogen Effluvium (TE). This occurs when the medication acts as a physiological stressor, prematurely shifting a large number of growing hairs from the Anagen phase into the resting Telogen phase. The hair does not fall out immediately but is shed naturally at the end of the Telogen phase.
Since the Telogen phase lasts months, noticeable shedding usually begins two to five months after starting the medication. This delayed onset makes connecting the hair loss directly to the drug difficult for many patients. The resulting hair loss is diffuse and non-scarring, meaning thinning occurs across the entire scalp rather than in specific bald patches.
Steps to Take When Experiencing Hair Loss
If you notice excessive hair shedding after starting Metoprolol, the first step is to schedule an appointment with the prescribing physician. It is necessary to determine if the medication is the actual cause of the hair loss or if another factor is responsible. Hair loss has many potential triggers, including significant emotional stress, nutritional deficiencies, recent illness, or underlying conditions like thyroid imbalance.
Your doctor will likely conduct a thorough evaluation to rule out these other causes before linking the issue to the beta-blocker. If the medication is suspected, the physician may suggest management options such as a dosage adjustment or switching to an alternative antihypertensive drug. There are many classes of blood pressure medications available, and an effective substitution can often be found that does not affect the hair cycle.
Never discontinue Metoprolol on your own, even if you are certain it is causing hair loss, as abruptly stopping the medication can lead to serious health risks, including a rise in blood pressure or worsening of angina. Any change to your treatment plan must be made gradually and under close medical supervision. In cases where switching the medication is not an option, the physician may recommend topical treatments like minoxidil to help stimulate hair regrowth.