What Medications Can Cause Hair Loss?
Medically reviewed by Lindsay Cook, PharmD
Hair loss may occur as a side effect of certain medications that interfere with hair growth or cause hair to shed.
Medications that can cause hair loss include:
Mood stabilizers
Antithyroid medications
Hormonal medications
Most of the time, the hair loss is reversible, with hair growing back a few months after stopping or reducing the medication.
This article will cover medications that can cause hair loss, why it happens, and tips on preventing, stopping, or reversing this effect.
Getty Images / Viktoria Korobova
How Do Medications Cause Hair Loss?
Many commonly prescribed medications can cause temporary hair loss, baldness, and even permanent hair loss.
Medications can affect hair in two ways: by halting hair growth or causing hair to fall out early. Sometimes, both of these things can happen at once.
Hair Loss and Growth: Why Does It Happen?
Each hair strand goes through a cycle of growth, transition, and rest. The growth phase is called anagen and can last from a few months to a few years. During anagen, the hair follicle produces hair continuously.
The next phase is a transitional phase. It is called catagen. During this phase, the hair follicle shrinks, and hair growth slows down.
The resting phase is called telogen and lasts for about 100 days. During this time, the hair remains anchored inside the follicle. Hair shedding occurs only when the follicle re-enters the anagen phase and produces a new hair shaft.
Types of Medication-Induced Hair Loss
Anagen effluvium is the process in which a medication causes hair loss by halting hair growth. With anagen effluvium, hair loss usually occurs within days or weeks of starting the medicine.
Hair loss can be severe and sudden, affecting a lot of hair at once. Sometimes, hair can be easily plucked out, and it may look different.
Hair loss is usually temporary, but it can take a few weeks for hair to start growing back. Anagen effluvium is commonly associated with anticancer medicines and radiation therapy. Anticancer drugs cause this type of hair loss by damaging hair cells that grow quickly so that they can target fast-growing cancer cells.
When a medication causes hair loss through telogen effluvium, hair sheds excessively. In the human scalp, the telogen phase typically lasts about three months, at the end of which the telogen hair sheds.
Telogen effluvium causes the shedding to happen prematurely. It may take one to six months before hair loss is noticeable. This cause of hair loss can be challenging to identify, given the delay between the trigger and the onset of hair loss.
With telogen effluvium, hair loss may not be severe and may not affect much hair. Usually, the hair loss goes away on its own without any treatment.
Medications That Can Cause Hair Loss
Medications that cause hair loss through telogen effluvium include:
Retinoids, including acitretin, isotretinoin, and Tazorac (tazarotene)
Antifungals, including Diflucan (fluconazole) and Vfend (voriconazole)
Mood stabilizers, including valproate/divalproex, Lithobid (lithium), and Wellbutrin (bupropion)
Blood thinners, including Jantoven (warfarin) and Heparin injections
Cholesterol-lowering drugs, including Lopid (gemfibrozil)
Antithyroid medications, including iodine, thiouracil, and carbimazole
Hormonal medications, including contraceptives, hormone-replacement therapy for women (estrogen or progesterone), male androgenic hormones, and all forms of testosterone and anabolic steroids
Antihypertensives (blood pressure lowering drugs) including Tenormin (atenolol), Lopressor (metoprolol), Corgard (nadolol), and Inderal LA (propranolol)
Medications that cause hair loss through anagen effluvium include:
Chemotherapeutic agents, including doxorubicin, Cytoxan (cyclophosphamide), Trexall (methotrexate), and Hydrea (hydroxyurea)
Retinoids
Retinoids are a class of medicines derived from vitamin A. They help treat certain skin conditions, such as acne. Hair loss is a reported side effect of oral retinoids, such as isotretinoin.
The extent and severity of hair loss usually depend on the dosage and duration of the treatment. If you experience hair loss while taking retinoids, your healthcare provider may adjust your dosage or advise you to stop taking the medication.
Antifungals
Antifungals are prescribed to treat fungal infections. Hair loss takes about three months after starting the medication.
Fortunately, hair loss caused by antifungals is reversible, and complete regrowth can be expected within three to six months after stopping or reducing the dosage.
Some antifungal medications have a lower risk of causing hair loss. In a clinical trial, 82% of people who were off voriconazole, an antifungal, for three months reported that their hair loss had stopped, with regrowth noted in 69%. This included those who had switched to two other antifungal drugs: itraconazole or posaconazole.
Mood Stabilizers
Mood stabilizers are commonly used to treat certain mental health conditions, like depression or bipolar disorder and sometimes epilepsy. Some of these medicines have a higher risk of causing hair loss than others.
Valproate/divalproex can cause hair loss, which usually becomes noticeable three to six months after starting the medication. The amount of hair loss is directly proportional to the dose. It can also cause other hair-related effects, such as curling, graying, and changing the appearance or texture.
Your healthcare provider may manage hair loss seen with these treatments by lowering your dose, stopping your medication, or recommending complementary hair care support, such as vitamin and mineral supplements.
Hair loss associated with valproate is usually reversible, with hair regrowth happening within two to three months after stopping the medication or reducing the dose.
Other mood stabilizers, such as lithium, selective serotonin reuptake inhibitors (SSRIs), and bupropion may also cause hair loss.
Hair loss with SSRIs and bupropion, although possible, is not as common. If you experience hair loss, your healthcare provider will evaluate the potential benefits of switching to another medication versus the risks of stopping the medication.
Blood Thinners
Depending on the specific drug, around 30% to 40% to up to half of people who take blood thinners (anticoagulants) may experience hair loss. Hair loss is more frequently observed in women than men.
After stopping the medication, hair regrowth may take up to three months. The incidence of hair loss with these medications may depend on your dose, age, and duration of treatment.
Blood Pressure Medications
Some blood pressure medications have been known to cause hair loss. These include beta blockers like propranolol and metoprolol. These drugs may cause hair loss or brittleness.
Antithyroid Medications
Medications that treat thyroid disorders may cause hair-related effects, such as hair loss, dryness, or brittleness. However, thyroid conditions can also contribute to hair thinning and shedding, so it might be difficult to know whether the hair loss is due to your medication or the condition.
Chemotherapy
Many people receiving chemotherapy experience hair loss as a common side effect. Hair shedding usually starts within seven to 14 days of the first administration, and hair loss becomes evident one to two months after. In some cases, especially in those who take multiple cycles of chemotherapy, hair loss may be almost complete.
Takeaway
This is not a comprehensive list of medications that may cause hair loss. For more information, please consult your healthcare provider or pharmacist.
How to Treat Medication-Induced Hair Loss
The step is to identify what's causing your hair loss and consult your healthcare provider before stopping your medication. They can help you find an alternative medication and ensure a safe switch if necessary. Be patient, though, as hair regrowth after discontinuing the medication may take several months.
In some cases, you may not be able to stop the medication causing your hair loss. For this, Rogaine (minoxidil) or Latisse (bimatoprost) may help.
Minoxidil stimulates hair growth and should be used with other treatments. It takes six to 12 months to see results. You must continue using it daily even if you see regrowth.
Bimatoprost is a prescription drug that promotes eyelash growth.
Other treatments for hair loss include:
Scalp cooling
Injections of corticosteroids or platelet-rich plasma
Laser therapy
Consult your healthcare provider or dermatologist for advice on the best treatment option.
Summary
Hair loss is a common side effect of many medications. It can happen in two ways: by stopping hair growth or causing hair to shed early.
Medications that may cause hair loss include retinoids, blood pressure medications, chemotherapy, and more.
Most of the time, the hair loss is reversible, with hair resuming growth a few months after stopping or reducing the medication.
If it is impossible to stop taking the medication causing hair loss, several alternatives may be considered, such as medications for hair growth (e.g., Rogaine) or other methods like scalp cooling.
Reach out to your healthcare provider if you notice increased hair loss when taking a medication. They may lower your dosage or prescribe an option less likely to affect your hair.
Read the original article on Verywell Health.
