Written by Shawn Candela for Avima.com

Accutane is the former brand name of isotretinoin, a retinoid most commonly used to treat severe and long-lasting cases of acne. Typically, isotretinoin is prescribed in small amounts at the beginning of treatment and increased gradually over a period of at least 16 weeks, at which point approximately 85 percent of patients are free of acne.

While treatment plans generally run between 16 and 24 weeks, the medication will continue to be effective for several months after cessation. The majority of isotretinoin users will be free of acne at the end of the treatment period, but it is not unusual for some patients to need a second dose of the medication to completely clear them of acne. If that is the case, a patient who has already been taking the medication for four months might expect to continue with treatment for another month or so before the acne is completely gone.

The prescribed dosage can also affect the response time in patients. Dosage amounts are determined by the dermatologist, and generally speaking, the higher the required amount, the longer the overall response time, simply because a patient will need to complete the entire prescribed dosage before treatment is concluded.

As an example, if a dermatologist prescribes a 100-pound person a dosage that is 50 times the patient’s body weight, that means that patient would need a total of 5,000 mg of isotretinoin for a complete reversal of his acne. Since a normal daily dosage of the medication is 40 mg, that patient would be required to continue taking it for 125 days, or a little more than four months.

It is also important to note that not all cases of acne respond equally to isotretinoin, or Accutane, and that the location of the acne can partially determine how long treatment lasts. Many patients, especially those treating only facial acne, will see positive effects after about a month of treatment, but others must endure frustrating delays — sometimes as long as four months — before seeing real results. This is particularly true if the patient is dealing with acne on broader areas, such as the back and chest.

Dermatologists have reported a wide range of response times. In one case, a Virginia doctor recounted his efforts to help a young man who had one of the worst cases of facial acne the doctor had ever seen, describing the teen’s face as “studded with large, ugly cysts. Nearly his whole face was covered with abscesses.”

After several months of treatment, the teen’s acne hadn’t responded, and the dermatologist recalled being nearly at wit’s end. But when his patient showed up for his regular appointment after more than four months of treatment, the acne was almost completely gone. The dermatologist took him off the medication for two months, then gave him one more dose to be sure. The acne did not return. In this case, then, the overall treatment period was longer than six months.

In almost all cases, patients report experiencing dry, peeling skin just before seeing results from isotretinoin. In fact, many patients go through an early stage — between seven and 10 days after beginning isotretinoin — in which the acne appears to worsen rather than improving, but that is actually part of the way the medication works. Many patients report effective relief from discomfort through the use of lotion and lip balm.

Once a patient’s treatment is over, some isotretinoin remains in her system for approximately two weeks. For this reason, doctors warn women to wait at least a month after ending treatment before trying to become pregnant.

Because isotretinoin causes a person’s epidermis, or outer skin, to become thinner, patients need to be careful about sun exposure throughout treatment and for up to a year after, as the skin heals. Patients also need to completely avoid any damaging treatments on the skin, such as those involving lasers or peels.