A lack of awareness relating to the interaction between smoking and medications used to treat conditions in old age is of particular clinical importance, since it may result in ineffective prescribing or in an exacerbation of chronic conditions: smoking can affect mean serum levels for drugs such as propranolol and theophylline, and is widely reported to decrease levels of anti-depressants, anti-psychotic, and opiate based medication; additionally, heavy smokers require one and a half times more insulin to control their diabetes than non-smokers [22]. The gene discussed is INS; the disease is diabetes mellitus.