The Committee on Safety of Medicines has demanded tighter controls on the prescribing of smoking cessation drug Zyban after receiving over 5,000 yellow card reports, including 126 of seizures, since it was licensed a year ago.The CSM recommends increasing the dose to twice daily from once after seven days rather than after four and using caution because of the risk of interaction with other medication.The drug has been prescribed to 419,000 people and pressure group ASH insists people should not be put off using it, saying it doubles the chance of smokers being able to quit.