Hepatic problems: Raised liver enzyme levels, liver inflammation (hepatitis), liver damage, liver failure Immune system problems: Decreased white blood cell counts including pancytopenia, leukopenia, lymphopenia, thrombocytopenia, agranulocytosis, and neutropenia, autoimmune reactions such as lupus erythematosus Psychological problems: Depression, anxiety, insomnia, increased or unusual dream activity, malaise Sensory problems: Complete loss of taste (ageusia), decreased taste (hypogeusia) and distorted taste (dysgeusia), often involving a metallic taste sensation and dry mouth, visual disturbances including blurred vision, green vision and double vision. In extremely rare cases, the loss or impairment of taste is permanent Skin problems: Rashes, hives (urticaria), skin irritation, itching, jaundice, Stevens–Johnson syndrome Other side effects: Fatigue, increased heart rate (tachycardia), hair loss (alopecia), decreased red blood cell count (anemia), muscle pain (myalgia), joint pain (arthralgia) In 2015 physicians reported that a patient with an MTHFR enzyme mutation (specifically the C677T variant) had developed an adverse reaction to Lamisil (headache, fatigue, and dizziness). Genetic testing revealed the MTHFR C677T mutation. It was noted that Lamisil interferes with the methylation cycle and that this can cause side effects in individuals with the MTHFR C677T mutation. Pharmacology Like other allylamines, terbinafine inhibits ergosterol synthesis by inhibiting squalene epoxidase, an enzyme that catalyzes the conversion of squalene to lanosterol. In fungi, lanosterol is then converted to ergosterol; in humans, lanosterol becomes cholesterol. However, as fungi and animals diverged around 1.1 billion years ago - there is enough difference in this enzyme that terbinafine preferentially binds fungal squalene epoxidase, making it selective for inhibiting ergosterol production in fungi without significantly affecting cholesterol production in mammals. This is thought to fatally disrupt the fungal cell membrane. Terbinafine is highly lipophilic and tends to accumulate in hair, skin, nails, and fat cells. This accumulation results in therapeutic levels of terbinafine even after 80 days following one week treatment of 250 mg/day. Different dosing schedules have been proposed such as 500 mg/day for one week or 250 mg/day for two weeks each followed by a drug-free period of three or two weeks, totaling 3 months of treatment including the drug-free periods. Such intermittent dosing schedules appear to be as effective as continuous regimens. Chemistry Terbinafine hydrochloride is a white crystalline powder that is freely soluble in methanol and dichloromethane, soluble in ethanol, and slightly soluble in water. Terbinafine is produced from olefin metathesis of 1,3-dichloropropene and neohexene followed by reaction with N-methyl-1-naphthalenemethanamine. Despite its name it does not