Olopatadine is an antihistamine (as well as anticholinergic and mast cell stabilizer), sold as a prescription eye drop manufactured by Alcon in one of three strengths: % solution or Pazeo in the United States , % solution or Pataday (also called Patanol S in some countries), and % or Patanol (also called Opatanol in some countries; Olopat in India). It is used to treat itching associated with allergic conjunctivitis (eye allergies ).  A steroid-free  nasal spray formulation is sold as Patanase , which was approved by the FDA on April 15, 2008.  It is also available as an oral tablet in Japan under the tradename Allelock , manufactured by Kyowa Hakko Kogyo. 
Levamisole (LEV) has been used as an immunomodulating medication in patients with recurrent aphthous ulcers and as an adjuvant for chemotherapy. LEV, with or without 5-fluorouracil (5-FU), induces multifocal inflammatory leukoencephalopathy (MIL). We identified 31 patients with LEV-induced MIL: 7 from our institution and 24 from a MEDLINE search. Twenty-one patients (%) had been treated with a combination of LEV and 5-FU, while 10 patients had been treated with LEV alone. The onset of MIL was delayed in patients who took LEV and 5-FU in combination compared with the patients treated with LEV alone ( +/- vs. 4 +/- wk, p < ). Colon cancer (%) was the most common indication for LEV administration. Gait ataxia occurred in 20 (%) patients, and dysphagia was noted in 16 (%) patients. Imaging studies revealed periventricular enhancement in 17 (%) patients and supratentorial lesions in 16 (%) patients. Cerebrospinal fluid studies showed lymphocytic pleocytosis in 10 of 21 (%) patients. Early diagnosis of MIL and discontinuation of LEV is essential, yielding good recovery in most cases. Treatment with corticosteroids and/or intravenous immunoglobulin may be needed for this serious inflammatory encephalopathy. Twenty-nine patients exhibited improved clinical status and imaging findings after initial steroid or immunoglobulin treatment. Plasmapheresis may be an alternative regimen for patients with steroid resistance.