Isotretinoin: one or two daily doses?
What is isotretinoin?
It is an orally administered retinoid (a derivative of vitamin A) used for the treatment of moderate-severe acne, with a high safety profile and very high efficacy . You can find more information here.
How is isotretinoin taken?
It is administered in capsule form for months, at a variable dose depending on the patient’s weight, usually between 0.5 – 1mg/kg of body weight/day, until a total drug dose of 120 – 150 mg/kg of body weight is reached. Since it is a derivative of vitamin A and it is fat-soluble (it dissolves in fat), it is best absorbed when taken together or just after a meal.
Is it better to take it in a single dose a day or split it into two?
According to the study by Ahmad H., the final efficacy of the treatment is the same regardless of how isotretinoin is taken. However, the rate of clinical adverse effects (dry lips and skin, eczema, dry eyes, cold sores, muscle or back pain, among others) is lower if the total dose is divided into two doses (morning and night). However, the increase in triglyceride levels attributable to isotretinoin is greater in patients who take two doses daily. The levels of transaminases and/or total cholesterol vary equally in patients who take one or two doses of the drug.
Therefore, in conclusion:
- The effectiveness of isotretinoin treatment is the same whether you take one or two doses a day.
- A single daily intake facilitates compliance with the treatment due to its simplicity.
- Clinical adverse effects (especially dryness) are usually more frequent in patients who take a single daily dose compared to those who take the same dose divided into administration in the morning and in the evening.
- The increase in triglyceride levels is greater in patients who take two doses a day compared to those who take a single dose. There are no differences in cholesterol or transaminase levels whether one or two doses are taken per day. It should be remembered that there are studies that link acne with an increase in blood lipids at baseline, without taking isotretinoin (you can get more information here).
Thus, the decision to take isotretinoin in one or two daily doses has little impact on the effectiveness of the treatment. On the one hand, it can make therapy more comfortable by taking two doses a day, as dryness is reduced; but it can increase non-compliance with treatment, since it is easier to forget some of the doses (in this way, the final daily dose would be lower and the treatment would take longer).
Opting for one or the other treatment modality will depend on the patient’s preferences and this aspect should be addressed in the initial approach to acne therapy.
REFERENCES
· Ahmad HM. Analysis of clinical efficacy, side effects, and laboratory changes among patients with acne vulgaris receiving single versus twice daily dose of oral isotretinoin. Dermatol Ther. 2015 Mar 5. doi: 10.1111/dth.12213. [Epub ahead of print]