See Figure 3. Algorithm for the management of type 2 diabetes from AFP (http://www.aafp.org/afp/20040801/489.html).
For patients who have been inadequately controlled on oral antidiabetic medications , the initial dose is typically 10 units/day or 0.1 to 0.2 units/kg/day. Initially, basal therapies are usually administered as a single dose in the evening. Where necessary, NPH insulin also may be given in 2 doses: 1 dose in the morning and 1 dose in the evening. The dose can be titrated in 1-, 2-, or 3-unit increments until target FPG levels are achieved. When initiating insulin, it is best to start low and increase the dose gradually until the target is reached (http://www.ispub.com).
If intermediate insulin is chosen, the amount can be calculated by dividing a patient's body weight in kilograms by four and using that number to determine the starting dose (resulting in one fourth of the regular dose) or by figuring the dose according to a ratio of 0.5 U/kg and using 25% to 30% of that amount as the initial dose. Patients who have insulin resistance often need between 0.75 and 1 U/kg and tend to tolerate the larger increases (http://www.postgradmed.com/issues/2003/06_03/3cooppan.htm)
In subjects with type 2 diabetes who are poorly controlled on oral antidiabetic medications, initiating insulin therapy with twice-daily BIAsp 70/30 was more effective in achieving HbA1c targets than once-daily glargine (Lantus), especially in subjects with HbA1c >8.5% (http://care.diabetesjournals.org/cgi/content/abstract/28/2/260).
The INITIATE (INITiation of Insulin to reach A1c TargEt) study provides guidelines for twice-daily initiation of insulin (aspart premix 70/30). Begin with 6 units twice a day if the FPG is 180 mg/dL or greater, and 5 units twice a day if the FPG is less than 180 mg/dL (http://www.medscape.com/viewarticle/567952).
References listed in the text above.
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