Accutane can potentially have a number of side effects, most of which are not particular to diabetes. Those need to be monitored regularly in a similar way in both diabetics and non-diabetics.
One Accutane side effect that I would want to watch closely in patients with diabetes, is the potential rise in cholesterol and triglycerides. Patients with diabetes are more prone to higher lipids. Accutane therapy can increase serum lipids as well. And increased lipids like cholesterol and triglycerides can affect the liver, which is also a potential side effect of Accutane
Dietary guidelines to help control that include avoiding saturated fats and simple carbohydrates. Simple carbohydrates should be avoided by patients with diabetes anyways, as they raise blood glucose levels.
I recommend that patients include only carbohydrates with a low glycemic index (glycemic index scales can be found easily online) and avoid those with a high glycemic index, like bread, potatoes, rice, pasta, candy, etc, as those can contribute to a rise in lipids.