Sounds like 'iso-tret-in-noin'

Easy-to-read medicine information about isotretinoin – what is it, how to take isotretinoin safely and possible side effects.

Type of medicine

 Also called

  • Acne treatment
  • Belongs to a group of medicines known as retinoids
  • Oratane®
  • Isotane®

What is isotretinoin?

  • Isotretinoin is used to treat severe acne.
  • It works by reducing excess oil production, clogged pores in the skin, bacteria that cause acne and inflammation.
  • It also has anti-inflammatory properties.
  • When used carefully, it can be very effective.
  • It is one of a group of medications known as retinoids.


  • The usual dose of isotretinoin is 10 milligrams or 20 milligrams once a day for 6 to 9 months.
  • Some patients may require higher doses, or twice daily dosing.
  • 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.

How to take isotretinoin

  • Take isotretinoin once a day, with a meal or a glass of milk.
  • Swallow the capsules whole – do not chew.
  • Keep taking isotretinoin until the prescribed course is completed.
  • It usually takes about 6 to 8 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.
  • Limit or avoid drinking alcohol while you are taking isotretinoin.
  • It is not harmful if you miss a dose of isotretinoin. If you forget to take your dose, take it as soon as you remember.
  • But, if it is nearly time for your next dose, just take the next dose at the right time. Do not take double the dose.

Special instructions

  • Blood test monitoring:
    • Before you start treatment, your doctor will send you for blood tests to exclude pregnancy, 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.
  • Isotretinoin can cause birth defects:
    • Before you start treatment, your doctor may send you for a pregnancy test to ensure that you are not pregnant.
    • Do not take isotretinoin if you are pregnant, or if there is a chance you could become pregnant.
    • If you are sexually active, ask your doctor about reliable contraceptive options.
    • Stop taking isotretinoin one month before you wish to become pregnant.
    • You may be asked to sign a consent form to make sure you have understood the seriousness of this. For example Isotretinoin_consent_form.BPAC (April 2009)
  • Inflamed, sore, red, cracked lips:
    • From the start of treatment, use a good emollient lip balm that has a sunscreen.
  • Dry, sensitive skin:
    • From the start of treatment, use a good, 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.
  • Increased sensitivity to the sun:
    • Avoid unnecessary sun exposure.
    • When outside, protect your skin by using a good sunscreen (SPF30+) and wear clothing that protects you from the sun.
    • Wear sunglasses when outdoors.
  • Dry, sensitive eyes:
    • Your eyes may become dry and itchy, especially if you wear contact lenses.
    • Applying artificial tear eye drops may be helpful.
  • Dry, crusted 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.
  • Donate blood:
    • Do not donate blood while taking isotretinoin and for 1 month after stopping it.
  • For a fuller list go to:

Possible side effects

Side effectsWhat should I do?
  • Headache
  • Tiredness
  • These are common symptoms of isotretionoin  that will likely go away with time.
  • If the side effects are severe or do not go away contact your health professional. 
  • Changes to eyesight and vision, especially at night
  • Take care when driving at night.
  • If this is a concern, discuss with your doctor.
  • Frequent mood changes, anxiety, depression, or worsening depression, aggressive tendencies, thoughts or attempts of suicide, and abnormal behaviours.
  • If you experience any of these symptoms, call your health professional immediately or ring Healthline on 0800 611 116
  • Severe headache with blurred vision.
  • Tell your doctor immediately or ring HealthLine on 0800 611 116
  • Severe diarrhoea, especially if it contains blood.
  • Tell your doctor immediately or ring HealthLine on 0800 611 116


  • Isotretinoin interacts with a number of medications such as some antibiotics, vitamin A products, and the mini-pill (oral contraceptive).
  • Check with your doctor or pharmacist before taking any other medicine or supplements.

Learn more

Credits: Written by Sandra Ponen, Pharmacist. Reviewed By: Dr J Bycroft, Health Navigator NZ Last reviewed: 11 Jun 2015