Prolonged dosing of Levamisole, or dosing higher that 150mg/D can over a period of months (4-5) at or near 3.7mg/kg can lead to vertigo, constriction of blood vessels related to balance. Daily Ginkgo 120mg per day standardized Swanson's brand, can help avoid this issue. If you experience Vertigo, Please be advised. The veins are not moving enough blood. Always stay at the minimum dose of LEV you can. If your infection is complicated with large red worms, try using a bit more clove and a bit less levamisole. A second clove cap 12 hours separated, or fill a few number 4 caps with Dr Clark 500mg caps. Serrapeptase and Ester C may also help keep the veins clear. Lumbrokinase Nattokinase