What medications can cause hair loss in females?

Medications That Can Cause Hair Loss in Females

Multiple medication classes can cause hair loss in women, with chemotherapy agents, anticoagulants, retinoids, valproic acid, lithium, and levothyroxine being the most common culprits, typically presenting as reversible telogen effluvium 1-3 months after initiation or anagen effluvium within days to weeks.

High-Risk Medications

Chemotherapy Agents

• Chemotherapy-induced alopecia affects approximately 65% of patients, typically starting 1-3 weeks after initiation and resulting in diffuse grade 2 alopecia (>50% hair loss) across the entire scalp, eyebrows, eyelashes, and body hair 1
• Hair regrowth begins 2-3 months after completing chemotherapy at approximately 1 cm/month, with 65% of patients experiencing changes in color and texture 2, 1
• Anthracycline-containing regimens and taxane-based chemotherapy are particularly associated with severe alopecia 1

Anticoagulants

• All anticoagulant drugs can produce hair loss, typically presenting as telogen effluvium 3, 4
• Hair loss becomes evident 2-4 months after starting treatment 4

Retinoids

• Acitretin causes hair loss in up to 75% of patients, with higher rates in women at doses exceeding 17.5 mg daily 5
• Isotretinoin demonstrates less hair loss compared to acitretin, with frank alopecia occurring in less than 10% of treated patients 5
• Hair loss is reversible and dose-dependent; consider dose reduction rather than complete discontinuation if acne control is adequate 5

Mood Stabilizers and Anticonvulsants

• Valproic acid precipitates alopecia in up to 12% of patients in a dose-dependent relationship, with incidences up to 28% observed with high valproate concentrations 6
• Valproate can also change hair color and structure 6
• Lithium causes hair loss in 12-19% of long-term users 6
• Carbamazepine-induced alopecia occurs at or below 6% 6

Endocrine Medications

Thyroid Replacement

• Levothyroxine can cause partial hair loss rarely during the first few months of therapy, but this is usually temporary 7

Aromatase Inhibitors and Tamoxifen

• Endocrine therapy-induced alopecia occurs in an estimated 4.4% (range 0%-25%) of patients, with tamoxifen showing the highest incidence at 25% 2
• Characterized by grade 1 alopecia primarily on the crown with recession of frontal and bitemporal hairline, typically developing between 6-18 months after therapy initiation 2, 1
• More frequent in post-menopausal women receiving aromatase inhibitors 2, 1
• In surveys, 22.4% of women on aromatase inhibitors reported hair loss and 31.8% reported hair thinning 2

Oral Contraceptives

• Diffuse hair loss can occur both while receiving oral contraceptives and after stopping the drug 3
• Telogen effluvium commonly occurs after discontinuation of drugs that prolong anagen, including oral contraceptives 8

Antihypertensive Medications

• Systemic or topical beta-adrenoceptor antagonists should be considered as possible causes of hair loss 3

Antithyroid Drugs

• All antithyroid drugs can produce hair loss 3

Psychotropic Medications

• Tricyclic antidepressants, maprotiline, trazodone, and virtually all new generation antidepressants may on rare occasions lead to alopecia 6
• Haloperidol, olanzapine, risperidone, clonazepam, and buspirone can rarely cause hair loss 6

Other Medications

• Salicylates and nonsteroidal analgesics cause hair loss in a very small percentage of patients 3
• Isolated cases reported with cimetidine, bromocriptine, levodopa, some hypocholesterolemic agents, and anti-infectious agents 3

Clinical Patterns and Timing

Telogen Effluvium Pattern

• Most common drug-induced pattern, presenting as diffuse, non-scarring alopecia that is reversible upon drug withdrawal 5, 8, 9
• Hair loss begins 1-3 months after medication initiation 5
• Resolution occurs within 3-6 months as the body adjusts 5

Anagen Effluvium Pattern

• Occurs within days to weeks of drug administration, primarily with antineoplastic agents 4
• Results from acute damage to rapidly dividing hair matrix cells 4

Management Approach

Diagnosis

• Diagnosis remains difficult; the only way to confirm drug-induced alopecia is to observe improvement after cessation of the suspected drug 3
• Rule out differential diagnoses including endocrine disorders, particularly in patients with aromatase inhibitor-induced alopecia 2

Treatment Strategies

• Discontinuation of the medication or dose reduction almost always leads to complete hair regrowth 6, 8, 9
• For chemotherapy patients, consider scalp cooling starting 20-45 minutes before infusion, with response rates of 50-65% (more effective with taxane-based regimens) 1
• For retinoid-induced hair loss, consider dose reduction rather than complete discontinuation if therapeutic control is adequate 5

Important Caveats

• This side effect must be recognized because it may be a source of poor compliance in some patients 3
• Alopecia might not be reported by some patients; physicians should proactively inquire 6
• Hair growth occurs at approximately 1 cm/month, so patience is required when evaluating treatment response 10, 1