Isotretinoin

What Is Isotretinoin and What Is It Used For?

Isotretinoin belongs to a class of medications called retinoids, which are chemically related to vitamin A. It is the 13-cis isomer of all-trans retinoic acid (tretinoin) and is one of the most effective treatments available for severe acne. The drug was first approved by the U.S. Food and Drug Administration (FDA) in 1982 and has since been used by millions of patients worldwide under various brand names including Accutane, Roaccutane, Claravis, and Absorica.

Isotretinoin uniquely addresses all four pathogenic factors that contribute to acne development. First, it dramatically reduces the size and activity of the sebaceous (oil-producing) glands, decreasing sebum production by up to 90%. Second, it normalizes follicular keratinization, preventing the formation of the plugs (comedones) that lead to acne lesions. Third, it has direct anti-inflammatory effects, reducing redness and swelling. Fourth, by reducing the oily environment, it indirectly decreases the colonization of Cutibacterium acnes (formerly Propionibacterium acnes), the bacterium most closely associated with inflammatory acne.

This medication is specifically indicated for severe acne, including nodular acne, conglobate acne (large interconnected abscesses), and acne with a risk of permanent scarring. It is also used when acne has not improved after adequate courses of standard therapies, typically including oral antibiotics combined with topical retinoids and benzoyl peroxide. Treatment must be initiated and supervised by a dermatologist or other physician experienced in the use of systemic retinoids.

The European Medicines Agency (EMA) and the British Association of Dermatologists (BAD) both recommend isotretinoin as a second-line treatment for severe acne after first-line therapies have failed, though in certain severe presentations with active scarring, it may be considered earlier in the treatment pathway. The drug has also been used off-label for other dermatological conditions such as rosacea and hidradenitis suppurativa, though these uses are beyond the scope of standard prescribing information.

What Should You Know Before Taking Isotretinoin?

Contraindications

There are several absolute contraindications to isotretinoin use. Understanding these is essential before starting treatment, as using isotretinoin in the presence of these conditions can lead to serious, potentially life-threatening complications.

The peanut and soya allergy contraindication is due to the capsule formulation, which contains soya oil. Patients with known allergies to these substances should not use soya-containing formulations. Some isotretinoin products do not contain soya, so your doctor may be able to prescribe an alternative formulation if appropriate.

Pregnancy and Breastfeeding

Isotretinoin can cause devastating malformations in a developing fetus, affecting multiple organ systems. These include craniofacial abnormalities (malformed ears, underdeveloped jaw), cardiovascular defects (heart malformations), central nervous system defects (hydrocephalus, microcephaly), and thymic and parathyroid gland abnormalities. The risk of miscarriage is also significantly elevated. These risks apply even if isotretinoin is taken for just a brief period during pregnancy.

Because of these severe teratogenic risks, all regulatory agencies worldwide have implemented strict pregnancy prevention programmes for isotretinoin prescribing. The requirements for women of childbearing potential include:

• Understanding the risks: Your prescriber must explain the teratogenic risk in detail, and you must acknowledge that you understand why pregnancy must be avoided.
• Effective contraception: You must use at least one highly effective method of contraception (such as an intrauterine device or hormonal implant) or two complementary methods (such as a hormonal pill and a barrier method like condoms). Contraception must begin at least one month before starting isotretinoin, continue throughout treatment, and continue for one month after stopping.
• Regular pregnancy testing: A negative pregnancy test is required before each prescription is dispensed. Tests are typically performed monthly. A final pregnancy test is recommended five weeks after the last dose.
• Monthly follow-up: Women must attend monthly consultations during treatment.
• No blood donation: You must not donate blood during treatment or for one month after stopping, as the donated blood could be given to a pregnant woman.

Isotretinoin passes into breast milk and must not be used during breastfeeding. For men, the levels of retinoids in semen are too low to pose a risk to a partner's unborn child. However, men should never share their medication with anyone.

Warnings and Precautions

Before and during isotretinoin treatment, several important precautions must be considered. These apply to all patients regardless of sex or age.

Liver function: Isotretinoin can cause elevated liver enzymes. Your doctor will order blood tests before, during, and after treatment to monitor liver function. If enzyme levels remain persistently elevated, your dose may need to be reduced or treatment discontinued.

Blood lipids: Isotretinoin commonly causes increased levels of cholesterol and triglycerides. These are monitored with regular blood tests. You should avoid or significantly limit alcohol consumption during treatment, as alcohol can worsen the effect on blood lipids and the liver. Patients with pre-existing high lipid levels, diabetes, obesity, or alcohol dependence may require more frequent monitoring.

Skin sensitivity: Your skin will become significantly drier and more sensitive during treatment. Use fragrance-free moisturisers and lip balm from the start. Avoid waxing, chemical peels, dermabrasion, and laser treatments during and for at least six months after treatment, as these can cause scarring and skin irritation. Use high-factor sunscreen (SPF 30 or higher) and avoid excessive sun exposure, tanning beds, and sunlamps.

Eye problems: Isotretinoin frequently causes dry eyes, which may make contact lenses uncomfortable. In rare cases, it can impair night vision, which may occur suddenly. Persistent dry eyes have been reported after treatment has ended. If you experience vision changes, contact your doctor promptly.

Inflammatory bowel disease: Isotretinoin has been associated with inflammatory bowel disease in rare cases. If you develop severe or bloody diarrhoea, stop taking isotretinoin and contact your doctor immediately.

Musculoskeletal effects: Joint pain, muscle pain, and back pain are common, particularly in physically active individuals. Reduce intense physical exercise during treatment. Rarely, isotretinoin may cause sacroiliitis (inflammatory back pain affecting the lower back and buttocks). Rhabdomyolysis (muscle breakdown) has been reported in rare cases, particularly with strenuous exercise.

Benign intracranial hypertension: Isotretinoin can cause increased pressure inside the skull (pseudotumour cerebri), particularly if taken simultaneously with tetracycline antibiotics (which is why this combination is contraindicated). Symptoms include severe persistent headache, nausea, vomiting, and visual disturbances. Stop the medication and seek immediate medical attention if these symptoms occur.

Blood sugar: In rare cases, isotretinoin has been associated with elevated blood glucose levels. Patients with diabetes, obesity, or alcohol dependence may require monitoring of blood sugar during treatment.

Children and Adolescents

Isotretinoin is not recommended for children under 12 years of age, as its safety and efficacy have not been established in this age group. In adolescents aged 12 and over, it should only be used after the onset of puberty. Special attention should be paid to musculoskeletal side effects in growing adolescents, and strenuous physical activity should be moderated during treatment. There are theoretical concerns about effects on bone growth in developing adolescents, though clinically significant growth impairment has not been demonstrated at standard doses.

How Does Isotretinoin Interact with Other Drugs?

Before starting isotretinoin, inform your doctor about all medications you are currently taking, have recently taken, or plan to take, including over-the-counter medicines and supplements. Some combinations can cause dangerous effects or reduce the effectiveness of your treatment.

Major Interactions (Contraindicated)

Significant Interactions (Use with Caution)

Additionally, alcohol consumption should be avoided or minimised during isotretinoin treatment because both substances are metabolised by the liver, and their combination increases the risk of hepatotoxicity and elevated triglycerides. There is no significant interaction with most common medications such as paracetamol (acetaminophen) at standard doses, ibuprofen, or standard antidepressants, though your prescriber should always be aware of your full medication list.

What Is the Correct Dosage of Isotretinoin?

Isotretinoin dosage is individually tailored based on body weight, severity of acne, and tolerance of side effects. The medication should always be taken exactly as prescribed by your doctor. Capsules should be swallowed whole with a drink or a mouthful of food during a meal, as absorption is significantly enhanced — approximately doubled — when taken with a high-fat meal.

Adults

After a few weeks, your doctor may adjust your dose depending on how you are responding. For most patients, the optimal dose lies between 0.5 and 1.0 mg/kg per day. Some patients may benefit from a lower dose maintained over a longer period, particularly if they experience significant side effects. Research suggests that achieving the recommended cumulative dose of 120–150 mg/kg is important for reducing the risk of relapse.

Adolescents (12 years and older, post-puberty)

Patients with Kidney Problems

Missed Dose

If you forget to take a dose, take it as soon as you remember. However, if it is almost time for your next scheduled dose, skip the missed dose and continue with your normal schedule. Do not take a double dose to make up for a forgotten one. Taking two doses close together increases the risk of side effects without providing additional therapeutic benefit.

Overdose

If you take too much isotretinoin, or if a child accidentally ingests the medication, contact your doctor, go to the nearest emergency department, or call your poison control centre immediately. Symptoms of acute overdose may be similar to vitamin A toxicity and can include severe headache, nausea, vomiting, facial flushing, chapped lips, and abdominal pain. Treatment is supportive, and symptoms typically resolve within a few days of stopping the medication.

What Are the Side Effects of Isotretinoin?

Like all medications, isotretinoin can cause side effects, though not everyone experiences them. Many side effects are dose-dependent, meaning they are more likely at higher doses, and most resolve when the dose is reduced or treatment is stopped. However, some effects may persist after treatment ends. Your doctor can help you manage side effects effectively throughout your course.

If you experience any side effects, talk to your doctor or pharmacist. You can also report side effects to your national pharmacovigilance authority. In the United States, reports can be made to the FDA MedWatch programme. In the United Kingdom, the Yellow Card Scheme operated by the MHRA accepts reports from both healthcare professionals and patients. In the European Union, each member state has its own reporting system.

Can You Drive While Taking Isotretinoin?

Night vision impairment is a recognised side effect of isotretinoin that can develop gradually or occur suddenly. Some patients have experienced a sudden decrease in their ability to see in dim light while driving at night. In very rare cases, reduced night vision has persisted after the end of treatment. If you notice any change in your night vision, you should stop driving in the dark and consult your doctor promptly.

Drowsiness and dizziness have been reported in very rare cases. If you experience these symptoms, you should not drive motor vehicles or operate heavy machinery. You are personally responsible for assessing whether you are fit to drive while taking this medication.

How Should You Store Isotretinoin?

Proper storage of isotretinoin is important to maintain the medication's effectiveness and prevent accidental ingestion by others, particularly children and pregnant women.

• Temperature: Store at or below 25°C (77°F). Do not freeze.
• Light protection: Keep the capsules in their original blister packaging inside the outer carton. Isotretinoin is light-sensitive.
• Accessibility: Keep out of sight and reach of children at all times.
• Expiry date: Do not use the medication after the expiry date printed on the packaging (indicated by “EXP”). The expiry date refers to the last day of that month.
• Damaged packaging: Do not use if the packaging appears damaged or shows signs of tampering.
• Disposal: Return any unused capsules to your pharmacy when treatment is finished. Do not dispose of medications in household waste or down the drain. Keep capsules only if your doctor instructs you to do so.

What Does Isotretinoin Contain?

The active substance is isotretinoin, available in strengths of 10 mg and 20 mg per soft capsule. Different manufacturers may offer additional strengths such as 5 mg and 40 mg capsules.

Common inactive ingredients (excipients) found in isotretinoin capsules include:

• Soybean oil (refined): Used as the capsule fill vehicle. Patients with peanut or soya allergy should not use products containing this ingredient.
• Hydrogenated vegetable oils and waxes: Used for capsule consistency.
• All-rac-α-tocopheryl acetate: A form of vitamin E used as an antioxidant preservative.
• Gelatin: Used for the capsule shell.
• Glycerol: Used as a plasticiser in the capsule shell.
• Sorbitol: A sugar alcohol. Patients with hereditary fructose intolerance should discuss this with their doctor, as sorbitol is a source of fructose.
• Colorants: Such as titanium dioxide (E171), sunset yellow (E110), or ponceau 4R (E124), depending on the strength and manufacturer. These may cause allergic reactions in susceptible individuals.

The exact excipient composition varies between manufacturers and between different strengths of the same product. Always check the patient information leaflet supplied with your specific product if you have known allergies or intolerances to any excipients.