Isotretinoin

• The usual dose of isotretinoin is 10 mg or 20 mg once a day until the acne has cleared (usually 3–5 months).
• Your doctor will then reduce your dose by half for a further 2–4 months to avoid the acne coming back and scarring. 
• Always take your isotretinoin exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much isotretinoin to take, how often to take it, and any special instructions.

• Timing: Take isotretinoin once a day, at about the same time each day.
• Food: Isotretinoin is best taken with or just after food. 
• Swallow the capsules whole – don't split or chew them.
• If you forget to take your dose, take it as soon as you remember. But, if it's nearly time for your next dose, just take the next dose at the right time. Don't take double the dose.

Risk of birth defects

Don't take isotretinoin if you are pregnant, or if there is a chance you could become pregnant.

• Before you start treatment, your doctor may arrange a pregnancy test to ensure that you're not pregnant.
• If you're sexually active, ask your doctor about reliable contraceptive options. You must use reliable birth control for at least 1 month before you start isotretinoin, the whole time you are taking isotretinoin and for at least 1 month after you finish taking it. Read more about methods of contraception.
• You may be asked to sign a consent form to make sure you have understood the seriousness of this, eg,  Isotretinoin consent form(external link).
• Note: no contraceptive precautions are required for males who are taking isotretinoin; birth defects have not been identified in children fathered by men who have taken isotretinoin.

Dry skin, lips, nostrils and eyes

Because isotretinoin reduces oil production in the skin, it can cause dry skin, dry mouth, chapped lips, dry nostrils and dry eyes. These effects can be uncomfortable. Here are some tips to manage them, but if you have any questions, ask your doctor or pharmacist for advice.

• Lips: from the start of treatment, use an emollient lip balm that has a sunscreen. It's important to apply the lip balm often during the day such as in the morning as soon as you wake up, after any food, snack or drink, last thing at night and any other time in between that your lips become dry. 
• Skin: from the start of treatment, use a non-perfumed moisturizing cream. Use non-soap cleansers, as these are less likely to irritate the skin, compared with a soap cleanser. Avoid beauty treatments such as chemical peels, dermabrasion and waxing during treatment, and for at least 6 months after stopping.
• Eyes: your eyes may become dry and itchy, especially if you wear contact lenses. Ask your pharmacist to recommend a suitable eye lubricant (also called artificial tears). Read more about eye lubricants. While you're taking isotretinoin, you may need to wear glasses instead of contact lenses.
• Nostrils: the inside of the nostrils may become dry and crusted and lead to mild nose bleeds. Applying a thin layer of petroleum jelly gently to the inside of the nose may help.

Increased sensitivity to the sun

Isotretinoin can make you more sensitive to the sun and your skin is more likely to burn.

• Avoid unnecessary sun exposure.
• When outside, protect your skin by using an oil-free sunscreen (SPF50+). Apply the sunscreen to all areas especially the face, neck and ears. Read more about using sunscreen.  
• Wear clothing that protects you from the sun.
• Wear sunglasses when outdoors.

Night vision may be affected

Night vision may be affected by isotretinoin. Good night vision is important for airline pilots and those flying after dark. Pilots taking isotretinoin or considering a course of isotretinoin must report to their national aviation authority to discuss how this treatment affects their flying privileges.

In Aotearoa New Zealand, this is the Civil Aviation Authority of New Zealand(external link) (CAA). Civil aviation licence holders, including Air Traffic Controllers, need to tell the CAA they are taking isotretinoin as this may affect flight safety. CAA considers the use of isotretinoin to be a change in medical condition.

Here are some more things to know when you're taking isotretinoin. Other things may be important as well, so ask your healthcare provider what you should know about.

• Keep taking isotretinoin until the prescribed course is completed. It usually takes a few weeks before you begin to notice a difference to the acne. Sometimes isotretinoin causes a worsening of acne about three to four weeks into treatment.
• Other medicines: Isotretinoin interacts with a few medications such as some antibiotics and vitamin A products. Check with your doctor or pharmacist before taking any other medicine or supplements.
• Breastfeeding: Don't take isotretinoin if you're breastfeeding.
• Donating blood: Donating blood by males and females on isotretinoin isn't allowed during treatment, and 4 weeks after treatment has finished. This is in case the blood is used for a pregnant woman.
• Avoid waxing for hair removal: Waxing can cause permanent scars in people taking isotretinoin. To avoid scarring, you mustn't wax while taking isotretinoin and for 6 months after you stop taking isotretinoin. This applies to hot wax and cold wax.
• Blood test monitoring: Before you start treatment, your doctor will send you for blood tests to check you're not pregnant, and to monitor your liver, blood fats and blood count. These tests should be repeated at least once during a 16 to 30-week course of isotretinoin.

Like all medicines, isotretinoin can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine. 

Read more about medicines and side effects and reporting a reaction you think might be a side effect.