Is it necessary to go a full 6 months on 2nd round of Isotretinoin? Can I get away with 4 months w/out it flaring up again?

Hi Casutton23,Isotretinoin can make the skin very dry because it targets and destroys oil glands- and not just oil glands on the face, but also lips, and less common eyes, skin, joints, and GI tract. Usually the course of isotretinoin is 6 months long which is based on reaching a particular dose based on your weight.  Once someone has reached this cumulative dose they have a 70% acne cure rate.  That means 30% of people who reach this same cumulative dose may fail treatment or their acne may return. However, if those in the failed group repeat the course, they have another chance to jump into that 70% cure rate group.  Increasing the daily dose to reduce the number of months on isotretinoin may be too irritating to the skin and you have to watch bloodwork and side effects.  I always caution to drink plenty of water, SPF30 everyday (or you will get red), ans hydrate your skin at night with a moisturizer that says "noncomedogenic" or "non-pore clogging" so you dont increase your risk for acne.  You could also take a lower-than-normal dose as your skin tolerates it but you will have to take it for more months. There is always wiggle room to make it a comfortable experience. Lastly, you are in the age group of that "second wave of acne" 30s to 40s. Isotretinoin is a good option for cystic acne.  If it flares monthly or in the "jawline" distribution you might benefit from looking at other treatments. 

Second course does not necessarily have to be 6 months. Considering your concern with side effects, you can try lower doses for longer period of time, to minimize the side effects.

The "cure" rate for acne is usually weight based and reaching a dosage of 120-150 mg/kg during the current course. You might be close to that based on your dosage and weight. As long as you get near this number, your acne should stay away. I have a number of patients who have side effects at higher dosages and we put them on a low dose (10-20 mg /week) for an extended period of time with minimal side effects. Good luck!