Retinoids (Tretinoin) — NZ Medication Guide
📋 Reviewed by a Registered Pharmacist NZ — This information is for general educational purposes only and does not replace professional medical advice. Always consult your doctor or pharmacist before starting, stopping, or changing any medication.
What is Retinoids (Tretinoin)?
Tretinoin (all-trans retinoic acid) is a topical vitamin A derivative used for acne vulgaris, photoageing, and keratinisation disorders. This medication is funded by Pharmac for acne under certain criteria.
What is Retinoids (Tretinoin) Used For?
Tretinoin is used topically for acne vulgaris (particularly comedonal and mild papulopustular acne), photoageing (fine lines, uneven skin tone), and keratinisation disorders. Oral tretinoin (ATRA) is also used in acute promyelocytic leukaemia (APL).
How Does Retinoids (Tretinoin) Work?
Tretinoin binds to nuclear retinoic acid receptors (RARs) and regulates gene transcription, promoting normal keratinocyte differentiation, increasing skin cell turnover, reducing comedone formation, and inhibiting the formation of new comedones. It also stimulates collagen synthesis in photoaged skin.
How to Take Retinoids (Tretinoin)
Topical tretinoin: apply a pea-sized amount to dry skin (dry for 20–30 minutes after cleansing) at bedtime. Start with low concentration (0.025%–0.05%) three times per week, gradually increasing frequency as tolerated. Always apply broad-spectrum SPF 50+ sunscreen during the day — tretinoin increases photosensitivity.
Common Side Effects of Retinoids (Tretinoin)
- Skin dryness and peeling (retinoid dermatitis — expected and usually settles)
- Stinging and burning
- Photosensitivity
- Erythema and irritation (especially initially)
- Purging (temporary worsening of acne in first 4–8 weeks — normal)
Serious Side Effects — Seek Medical Attention
Contact your doctor or call 111 immediately if you experience any of the following:
- Teratogenicity — absolutely contraindicated in pregnancy (topical tretinoin has lower systemic absorption than oral retinoids, but risk cannot be excluded)
- Severe irritant contact dermatitis
- Hyperpigmentation or hypopigmentation (in darker skin types if over-irritated)
Drug Interactions
Retinoids (Tretinoin) may interact with other medicines. Always inform your doctor and pharmacist of all medications you are taking. Key interactions include:
- Topical benzoyl peroxide (combined use increases irritation — apply at different times)
- Topical exfoliants (AHAs/BHAs — additive irritation)
- Waxing (avoid waxing treated areas — skin is fragile)
New Zealand Prescribing Information
Tretinoin 0.025% and 0.05% cream (Retin-A® and generics) is funded by Pharmac for acne. Patients must be counselled on the initial “purging” phase, consistent sunscreen use, and gradual introduction of the product. Avoid during pregnancy — women of childbearing potential should use effective contraception. Isotretinoin (oral) for severe acne is funded under Special Authority with strict pregnancy prevention requirements.
Frequently Asked Questions
Why does my skin get worse when I first start tretinoin?
The “purging” phase — where existing microcomedones are pushed to the surface and acne temporarily worsens — is a normal and expected part of starting tretinoin. It typically lasts 4–8 weeks and is a sign that the medicine is working. Persist with treatment; improvement follows.
Must I use sunscreen with tretinoin?
Yes — this is essential. Tretinoin increases the skin’s sensitivity to UV radiation. Unprotected sun exposure while using tretinoin can cause severe burning, hyperpigmentation, and undoes the anti-ageing benefits. Apply a broad-spectrum SPF 50+ sunscreen every morning without fail.
⚠️ Disclaimer: This page is for educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your doctor or a qualified health provider. In New Zealand, medication availability and funding may vary — check with Pharmac or your pharmacist for current information.
Reviewed by a Registered Pharmacist NZ
References & Further Information
The following New Zealand and international resources were used to inform this page: