Up in smoke. The metabolic imbalances (low potassium) from purging lend to cardiac rhythm disturbance. Smoking can cause at least temporary tachycardia - speeding up heart rate - and may initiate coronary and other artery spasm or narrowing. Low weight provides for more demands on the heart as well. The synergism of the two can lend to overall compromise - diminished immune function, heightened risk of illness.
Answer. The two conditions do not have any direct additive adverse effects to your health, but both can damage your health in the long run - for smoking: higher risk of heart disease, various cancer, copd, etc. Bulimia can cause GI reflux, nutritional deficit, dental damage. Both conditions are treatable, so you should check with your family doctor for treatment.