Isotretinoin: medication for the treatment of acne
Isotretinoin has revolusionised the treatment of acne since it became available in South Africa in 1984, according to the National Dermatology Working Group led by Dr Dave Presbury. It is the only treatment that affects all four aetiological factors implicated in the acne process namely:
- the production of sebum
- comedogenesis
- colonization of the skin surface and follicular duct with Propionibacterium acnes and monocyte chemotaxis with an anti-inflammatory effect.
Isotretinoin is the treatment of choice for
- severe acne (nodulocystic acne, and extensive acne involving the face and trunk)
- lesser degrees of acne, particularly where scarring is occurring
- where other options have failed or are unsuitable or not tolerated.
Isotretinoin can also be prescribed for other conditions: Seborrhoea, Gram-negative folliculitis, Rosacea, and Hidradentis suppurativa. More and more patients are failing to respond to long-term antibiotics, both topical creams or tablets. This is due to the increase in resistance of P.acnes to many antibiotics. Studies have shown that even people with mild to moderate acne may develop scars for which long-term management remains a problem. Scarring from acne may have long-term physical and emotional ramifications. Other treatments are slower in onset of action, and scarring may occur before they take effect.
Dosage and success rate
In 60 – 80 percent of people, the treatment can lead to a permanent cure at a dose between 0,5 – 1 mg/kg body weight per day for 16 – 20 weeks. New evidence suggest that a cumulative dose of 120 mg /kg body weight during the course at a daily dose of at least 0.75 mg/kg body weight may be more important than the duration of the treatment. If acne persists or recurs a second full course may be considered any time after a two month gap following treatment. Please note that some people – those with multiple macrocomedones and polycystic ovarian syndrome may take a while to respond to the treatment. In about 30 percent of patients, the acne becomes infected with the bacterium Staphylococcus aureus. Bacterial infections should be treated with the appropriate antibiotics. Note that tetracyclines should not be taken with isotretinoin.
With an expected 60 – 80 percent cure rate, 20 – 40 percent of people may need an extra oral antibiotics, hormonal treatment (Diane) or repeat isotretinoin. People who might need a second course, include:
