72 units seems quite a lot..... but I think it depends on your weight and how much you eat. I take 18 units of lantus every night and between 4-15 units of novarapid after each meal. (i weigh 65 kg/ 10 stone) Im 5 ft 11 and aged 23. (female) Are you very hungry on this dose? I think its best to take the minimum amount that you need otherwise it makes you extremely hungry and also makes you put on a lot of weight (the insulin itself AND the fact that being hungry makes you eat more)
*Diabetic for 9 years