Polycythemia vera is a type of blood cancer that causes excessive production of red blood cells. This may lead to blood clot formation and lead to other serious health issues. Jakavi 5mg Tablet kills or stops the growth of cancer cells and also prevents the multiplication of cancer cells. It is an effective, yet very toxic medicine and you should discuss the risks and benefits with your doctor. Avoid drinking alcohol or smoking while having this treatment and drink plenty of water to stay hydrated.