There are many categories of prescription drugs that have been reported to cause hair loss, and the medications listed below present a risk of temporary hair loss as a possible side effect. It is important to note that hair loss is only an infrequent possible side effect of these medications, and when it does happen, hair loss may occur after a few weeks or after years of use of a particular drug. Factors such as dosage, duration of treatment, and normal variations in how people respond to medications determine the degree of hair loss that may occur, if any. In most cases, hair growth resumes around three to four months following the discontinuation of the medication.
In addition to the following list of drug types and specific hair loss-causing drug examples, a much longer alphabetical list of drugs that have been reported to cause hair loss appears in Appendix 2.
Certain cholesterol-lowering drugs have hair loss as a possible side effect, including: clofibrate, gemfibrozil (Lopid).
Some Parkinson medications may cause hair loss in some people, including: levodopa (Dopar, Larodopa).
Common ulcer medications that may cause alopecia (hair loss) are: cimetidine (Tagamet), ranitidine (Zantac), and famotidine (Pepcid).
High blood pressure beta-blocker medications that have been noted to occasionally cause hair loss include: Atenolol (Tenormin), metoprolol (Lopressor), nadolol (Corgard), propranolol (Inderal), and timolol (Blocadren)
Common anticoagulants (blood thinners) that cause hair loss are: warfarin, coumarin, and heparin. A gout medication that may cause hair loss is: allopurinol (Zyloprim).
Arthritis medications that may cause hair loss include: penicillamine, indomethacin (Indocin), naproxen (Naprosyn), sulindac (Clinoril), methotrexate (Folex)
It has already been noted that vitamin A in excessive doses over a period of time can cause hair loss. Some medications that are vitamin A derivatives can also contribute to thinning hair, including: isotretinoin (Accutane), acitretin (Soriatane).
Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used to treat inflammation, fever, and pain, but in some cases they also cause hair loss. Common over-the-counter NSAIDs such as ibuprofen and naproxen are included in this category of drugs. Prescription NSAIDs that may also cause hair loss include: celecoxib (Celebrex), diclofenac (Voltaren), etodolac (Lodine), fenoprofen (Nalfon), indomethacin (Indocin), ketoprofen (Orudis, Oruvail), oxaprozin (Daypro), nabumetone (Relafen), and sulindac (Clinoril).
Hormone Replacement Therapy drugs, as well as many oral contraceptives (birth control pills), contain progestins, estrogens, and estrogen-like compounds (“female” hormones) that can cause hair loss in some women. It is significant to note that the same medications are frequently prescribed to reverse hair loss, as well. It just happens that in some women, they help stop hair loss, while in others they cause hair thinning.
Anabolic steroids are synthetic androgens commonly referred to as “male hormones.” In addition to being prescribed for certain medical conditions, anabolic steroids also have a history of being used by body-builders seeking to increase their muscle mass. In men with a genetic predisposition to hair loss, the excessive use of these medications can cause premature baldness. Testosterone in various forms is used as a medication with brand names including Testex, Depo-Testosterone, and Delatestryl. Other anabolic steroid hormone medications that can cause hair loss include fluoxymesterone (Halotestin), methyltestosterone (Android, Metandren, Oreton, Testred, Virilon), stanozolol (Winstrol), and danazol (Danocrine).
Thyroid gland disorders can result in hair loss; however some thyroid medications such as thiouracil can also cause hair thinning as well.
Chemotherapy drug treatment almost always causes hair loss because the drugs target rapidly dividing cells typical of cancer. The cells in a hair follicle that produce the hair shaft also divide rapidly, and actively producing hair follicles are shut down by chemotherapy drugs. This type of hair loss is called anagen effluvium, and it is characterized by relatively sudden and massive hair shedding. Since approximately ninety percent of all hair follicles are actively growing hairs at any given time, with the other ten percent resting or just waiting to shed hairs, the typical effect of chemotherapy drugs is near total hair loss in a short period of time.
When undergoing chemotherapy, hair loss often begins two to three weeks after the first treatment and progresses over the next one to two months. Usually most or all the hair on the scalp is shed, and with prolonged treatment there may also be loss of hair on the face, arms, legs, underarms, and pubic area. The hair usually begins to grow back about three to four months following the last chemotherapy treatment, however hair only grows about one-half inch a month, and it may take several months before good coverage is achieved.
Hair loss from chemotherapy often has a devastating psychological effect on cancer patients, and there have been attempts to reduce the degree of hair loss with various devices and drugs. One method to reduce hair loss involves the application of a tourniquet around the scalp to restrict blood flow during chemotherapy, in an attempt to reduce the amount of chemotherapy drugs received by the hair follicles. Another method involves chilling the scalp with various cooling devices, also to reduce blood flow and limit the effect of the chemotherapy drugs. And there have been advances with medications that temporarily stop the hair follicles from growing hair, and as a result reduce their absorption of the chemotherapy drugs. None of these methods work perfectly, and all can increase the risk of cancer cells surviving in the hair follicles.
Common chemotherapy drugs that routinely cause hair loss include: bleomycin, cyclophosphamide, cytarabine, dactinomycin, daunorubicin, doxorubicin, etoposide, fluorouracil, and methotrexate.