Serum drug level-related sodium valproate-induced hair loss
A 26-year-old woman weighing 36 kg, suffering from GTC seizures since past six years and hypothyroidism since past 14 years, came to our therapeutic drug monitoring (TDM) out patient department for routine drug monitoring. She complained of hair loss since ten months after starting valproate.\nDuring last five years, she was receiving tablet phenytoin 100 mg thrice a day with calcium tablets along with thyroxin 50 μg tablets once daily prior to valproate. Her electroencephalography (EEG) was normal and showed no evidence of neuronal hyper excitability; CT scan did not reveal any significant intracranial abnormality. During the course of illness she had fluctuations in thyroid hormone levels in 2005. Thyroid stimulating hormone levels (>100 μIU/ml; normal 0.3 - 0.5 μIU/ml), reduction in total thyroxin (3.16 μg/dl; normal 4.5 - 12 μg/dl), and free thyroxin was reduced (0.46 ng/dl; normal 0.7-1.8 ng/dl). The dose of thyroxin was increased to 75 μg and she was stable and continued with phenytoin with regular drug monitoring. In December 2009, she developed long term ADRs of phenytoin like hypochromic, microcytic anemia with macrocytosis, and gingival hyperplasia. Phenytoin was replaced with valproate chrono 300 mg twice daily, following which her hemogram and peripheral blood smear showed normocytic picture, but three months later she complained hair loss. She consulted a homeopathic doctor for hair loss. She was prescribed arnicated hair oil (Arnica montana, cantharis, jaborandi, and lycopodium in gently perfumed oil base) for local application, but no improvement was observed.\nDrug-induced hair loss was suspected. She was referred to dermatologist for further confirmation. The result of trichogram revealed an increase in resting (telogen) and dystrophic hair at the expense of growing hair (anagen), which is classical of drug- induced hair loss. The signs of common conditions like anemia and hypothyroidism, which are often associated with diffuse hair loss, were excluded since hemogram, thyroid hormones profile, and electrolytes were normal.[]\nSubsequently, we informed the patient's neurologist that she was probably suffering from a valproate-induced telogen effluvium and suggested its substitution with an alternative drug. Valproate was substituted with levetiracetam 200 mg tablet daily. The new drug was well-tolerated and also effective in preventing seizures. In our case, the temporality between valproate intake, drug levels, and hair loss was evident, and after stopping valproate, hair loss retracted.