All are true about levamisole EXCEPT :

Levamisole is an immunomodulator acting as immunostimulant at low doses and immunodepressant at high doses. It was used as anti-helminthic and causes depolarization by stimulating nicotinic receptors. It is used for the treatment of colorectal carcinoma in combination with 5-FU. It is slow to act in psoriasis and requires two-day therapy per week for prolonged periods.