Active Ingredient: Isotretinoin
The dose can then be adjusted according to clinical response and presence or absence of side effects. The range is usually 16—30 weeks, with a mean between 16 and 20 weeks with patients receiving 0.
Studies to derive a cumulative dose for maximum benefit and reduced relapse rate have confirmed that there is a definite effect of both dose and duration of therapy but that there is not a priori pharmacokinetic reason to support the concept of accumulation of drug or a cumulative dose effect.
Table 2 outlines poor prognostic factors. Eighty-five percent of patients who receive a dose of 0. Low-dose courses of isotretinoin have been used successfully in mature adults with persistent and late-onset acne.
A typical approach consists of 0. Ninety-one percent will be clear of acne using this regimen 46, 47 but relapse is disappointingly frequent.
Further courses of therapy are usually successful when required. There are no reports of cumulative toxicity from using repeat courses and tachyphylaxis has not been noted.
Side Effects Isotretinoin has many side effects but most are predictable and rarely interfere with the patient management. Teratogenicity is well recognized and regarded as one of the most serious potential adverse effects.
Discussion about the teratogenicity and recognized side effects should be recorded in the notes at each visit, and patients should be given appropriate written information. Mood changes including depression are common among adolescents and have been reported in acne patients treated with isotretinoin.
Two studies that looked at spontaneous reports of side effects for the FDA in the USA 53, 54 found little or no increase in psychiatric disease including depression and suicide over the background prevalence in the adolescent population.
A further study of general practice databases in Canada and the UK showed similar findings as have subsequent studies.
Table 3 Open in a separate window In a study by Amichai et al. Patients at increased risk for early relapse included younger patients with acne of relatively recent onset, those with truncal acne, and women with polycystic ovary syndrome.
In our study, relapse rate had not any relation with patient's weight, age, and anatomical location of lesions.