Is alopecia/hair loss a known side effect of mirtazapine (Remeron)?/nA 58-year-old woman has notice

Fråga: Is alopecia/hair loss a known side effect of mirtazapine (Remeron)? A 58-year-old woman has noticed diffuse hair loss since treatment with mirtazapine was commenced three months earlier. The treatment has been discontinued but the patient still experiences hair loss. Concomitant drugs: lithium, levothyroxine (Levaxin).

Sammanfattning: There are some unpublished case-reports describing alopecia/hair loss as a side effect of mirtazapine. It should also be noted that alopecia is a common side effect of lithium. The hair loss may appear within weeks to years after starting medication.

Svar: Alopecia and hair loss have been described as an uncommon adverse effect of antidepressive as well as antipsychotic agents in general (1-7).

In premarketing studies of mirtazapine, alopecia was observed in 1/100 to 1/1000 patients (8). In the Swedish register on adverse drug reactions (Swedis) there are two reports on defluvium in association with mirtazapine (9). The international WHO-database on adverse drug reactions (Intdis) contains 30 reports on mirtazapine associated alopecia (10). It should be noted that the WHO database does not include a homogeneous evaluation of reported cases due to differences among reporting countries. The manufacturer has received 10 reports on alopecia after treatment with mirtazapine (15-60 mg). In these cases, the hair loss appeared two to three weeks after start of therapy. Since the patients almost exclusively were treated with concomitant drugs, it has not been possible to assess causality (11).

Alopecia is a known side effect in patients managed on lithium (5-7) and has been reported to occur in 12-19% of long-term users. Alopecia may occur within weeks to years after starting medication; usually it takes four to six months to develop appreciable hair loss. A long duration of lithium exposure has been discussed to be related to the occurrence of this side effect (7). Furthermore, lithium is known to cause hypothyroidism, a condition that may give rise to hair changes. However, when patients become euthyroid, alopecia is usually reversible (7,12).