8 Types of Drugs That May Cause Hair Loss

The patient was depressed. She had kidney disease, endured regular dialysis and had undergone an aggressive medical regimen after doctors discovered blood clots. But that wasn’t what was dimming the 49-year-old’s spirits.

“My hair is falling out,” she lamented.

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Her doctors suspected the cause. She had been prescribed warfarin, an anticoagulation drug, to deal with her clotting issue. Within three weeks of switching to an alternative drug, apixaban, her hair stopped falling out — and eventually it grew back.

Like turning gray, hair loss can be a natural part of aging. But alopecia, the medical term for hair loss, is a complex condition with many variations, from slow-progressing balding (referred to as male- or female-pattern hair loss) to more rapid and patchy loss (alopecia areata is a common form). Genetics, hormonal changes, inflammation and even certain diseases — including, in some cases, COVID-19 — can trigger temporary or permanent hair loss. And prescription drugs may also trigger excessive and sudden shedding.

The secret life of your hair

Each hair on your head has its own individual life cycle: A strand grows between two and eight years. Then, in a period of two or three weeks, it stops growing and rests for three to four months before detaching from the follicle. Your head of hair is a mixture of 85 to 90 percent actively growing hair and hair that’s resting and waiting to shed.

But when the body experiences a trauma, sudden, substantial shedding can occur. Triggers can include an acute illness, stress, a severe nutritional deficiency, rapid weight loss — or a drug that proves toxic to hair follicles. Drugs can be the culprit for a condition known as drug-induced telogen effluvium, which leads to increased shedding on top of the scalp a few months after exposure.