Retinoids are vitamin-A–related medicines that regulate epithelial differentiation, follicular keratinisation, inflammation, sebum production and (for selected agents) tumour-cell differentiation or apoptosis. They range from nightly topical acne preparations to specialist-only systemic drugs with serious fetal, hepatic, lipid, skeletal and neuro-ocular toxicity. This page is an emergency-medicine and clinical-pharmacology reference: always reconcile the product label, local formulary and specialist advice before prescribing.
Learning objectives
- Explain vitamin-A biology and retinoic-acid receptor signalling.
- Classify first-, second- and third-generation retinoids and match each drug to its practical indication.
- Prescribe topical tretinoin, adapalene, tazarotene and alitretinoin safely, including application technique and irritation management.
- Recognise the specialist requirements for oral isotretinoin, acitretin and bexarotene: patient selection, dose titration, laboratory monitoring and contraception.
- Identify interactions and rapidly manage pregnancy exposure, pancreatitis, severe hypertriglyceridaemia, hepatotoxicity, pseudotumour cerebri and severe mucocutaneous reactions.
1. What are retinoids?
Retinoids are natural or synthetic compounds that produce biological effects similar to vitamin A (retinol) and its active metabolite, all-trans-retinoic acid (tretinoin). Their clinical effects depend on receptor selectivity, tissue penetration, formulation and whether exposure is topical or systemic.
Historical development
- Vitamin A was recognised as important for epithelial integrity and vision; dermatologic use was reported in the 1940s.
- Topical tretinoin was investigated for abnormal keratinisation in the 1960s and became an acne treatment in the late 1960s.
- Etretinate/acitretin were developed for psoriasis; isotretinoin became a transformative treatment for severe nodulocystic acne in the early 1980s.
- Bexarotene (an RXR-selective retinoid) was introduced for refractory cutaneous T-cell lymphoma (CTCL); topical alitretinoin was developed for AIDS-related Kaposi sarcoma.
Natural retinoids and carotenoids
| Compound | Main physiological role | Clinical teaching point |
|---|---|---|
| Retinol | Transported/storage form; reproduction and epithelial maintenance | Excess vitamin A adds to retinoid toxicity; avoid unsupervised supplements during treatment. |
| Retinal | Visual-cycle chromophore | 11-cis-retinal combines with opsin; deficiency causes night blindness. |
| Retinoic acid | Gene regulation, growth and epithelial differentiation | Does not substitute for retinal in vision or retinol in all physiological functions. |
| Carotenoids (for example, beta-carotene) | Dietary precursors; some convert to retinol | Conversion is regulated and does not make high-dose supplements harmless. |
Approximate adult dietary vitamin-A requirements are often taught as 0.8–1.0 mg retinol activity equivalents daily (about 2,400–3,000 IU, depending on the unit system used). This nutritional value is not a treatment dose and should never be substituted for a prescribed retinoid.
2. Molecular mechanism: RAR, RXR and gene regulation
- Entry and binding proteins: all-trans-retinoic acid (ATRA) enters cells and is buffered/transported by cellular retinoic-acid binding proteins (CRABP-I and CRABP-II). Isotretinoin (13-cis-retinoic acid) is isomerised intracellularly to active species; it has little direct affinity for RAR/RXR in standard pharmacology teaching.
- Nuclear receptors: retinoic-acid receptors (RAR-alpha, beta and gamma) and retinoid-X receptors (RXR-alpha, beta and gamma) form homo- or heterodimers. RAR/RXR heterodimers bind retinoic-acid response elements (RAREs) in DNA.
- Transcription: ligand binding releases corepressors and recruits coactivators, changing transcription of genes controlling keratinocyte differentiation, proliferation, cytokines, lipid metabolism and apoptosis.
- Non-genomic/anti-inflammatory effects: retinoids reduce AP-1 activity and downstream inflammatory mediators, including selected cytokines, tumour-necrosis factor signalling, neutrophil migration, leukotriene B4 and nitric-oxide pathways.
RAR agonism explains normalisation of follicular keratinisation and teratogenicity. RXR-selective stimulation (bexarotene) explains its CTCL activity but also its characteristic hypothyroidism and marked dyslipidaemia. Topical retinoids concentrate effects in skin; oral agents expose every organ system.
3. Retinoid generations and examples
| Generation | Representative agents | Practical characteristics |
|---|---|---|
| First generation: non-aromatic | Tretinoin, isotretinoin, alitretinoin, retinoyl glucuronide, fenretinide | Closely resemble natural retinoids; strong differentiation and irritation/teratogenic potential. |
| Second generation: mono-aromatic | Etretinate, acitretin, motretinide | Systemic antipsoriatic activity; acitretin has a long reproductive precaution because ethanol can regenerate etretinate. |
| Third generation: poly-aromatic | Bexarotene, tazarotene, tamibarotene, arotinoid sulfones, adapalene | More receptor-selective or photostable; adapalene is a naphthoic-acid derivative with better topical tolerability. |
| Investigational/newer examples | Seletinoid G, etretin, arotinoids and other receptor-selective analogues | Useful for understanding drug development; availability and indications vary by country. |
4. What retinoids do in skin and other tissues
Keratinisation
Decrease abnormal corneocyte adhesion, normalise follicular plugging and epidermal hyperproliferation, and promote orderly differentiation. Increased transepidermal water loss explains dryness and peeling.
Sebaceous glands
Isotretinoin is the strongest systemic sebaceous suppressant: sebaceous-gland size may fall by about 90% and sebum output by roughly 70–90% during treatment. This is central to its acne efficacy.
Inflammation
Reduce AP-1 and inflammatory transcription, neutrophil migration and selected cytokines. Adapalene and tazarotene therefore have anti-inflammatory activity in addition to comedolysis.
Antitumour differentiation
Alitretinoin and bexarotene can induce differentiation or apoptosis in selected malignant cells, explaining their specialist oncology indications.
Physiological retinoid exposure can support epithelial repair, whereas supraphysiological exposure may impair wound healing and produce fragile, inflamed skin. Do not apply a retinoid to an open, infected or severely excoriated wound unless a specialist specifically directs it.
5. Topical retinoids
5.1 Tretinoin (all-trans-retinoic acid)
Mechanism: activates RARs, reduces corneocyte cohesion, increases microcomedone turnover and promotes keratinocyte differentiation. It also remodels dermal matrix over time, which explains gradual photoageing benefit.
| Common preparations | Typical use and dose | Key counselling |
|---|---|---|
| Cream/gel/lotion 0.01%, 0.025%, 0.05% or 0.1% | Acne vulgaris: apply a pea-sized amount as a thin film to the entire acne-prone area once nightly, not only to visible spots. Start 2–3 nights weekly if sensitive, then increase. | Wash gently, pat dry and wait 20–30 minutes before applying. Improvement may take 6–12 weeks; acne can look worse briefly at initiation. |
| Microsphere 0.04% or 0.1% | Nightly acne treatment when reduced irritation is desired; use a thin film. | Do not combine at the same time with harsh scrubs, waxing, alcohol-based products or multiple irritant acne medicines. |
| Low-strength cream/gel | Photoageing/fine lines: usually a thin nightly application under dermatology supervision. | Daily broad-spectrum sunscreen and moisturiser are essential; this is a long-term cosmetic/dermatologic indication, not an emergency treatment. |
Adverse effects: erythema, burning, dryness, peeling, pruritus, photosensitivity and irritant dermatitis. Reduce frequency, use moisturiser and pause until the barrier recovers if severe. Tretinoin may cause temporary post-inflammatory pigment change, especially in darker skin, if irritation is uncontrolled.
Interactions/avoidance: use caution with benzoyl peroxide (separate application if the formulation is not designed as a fixed combination), sulfur, resorcinol, salicylic acid, abrasive cleansers and other peeling agents. Do not apply to eyes, lips, mucosa, sunburn, eczema flares or broken skin. Pregnancy recommendations vary by product, but topical retinoids are generally avoided during pregnancy and breastfeeding unless a specialist judges benefit to outweigh risk.
5.2 Adapalene
Adapalene is a photostable, selective retinoid-like naphthoic-acid derivative with comedolytic and anti-inflammatory effects. It is usually better tolerated than tretinoin and is suitable for once-daily acne regimens.
- Dose: 0.1% gel/cream or 0.3% gel: apply a thin film to the entire affected area once nightly after gentle cleansing and drying. Do not exceed once daily; more product increases irritation, not efficacy.
- Combination therapy: may be used with benzoyl peroxide or topical antimicrobials when a product label or treatment plan supports it. Apply separate irritant products at different times if needed.
- Adverse effects: dryness, scaling, erythema, stinging, burning and photosensitivity. Severe swelling, blistering or intense pain indicates a significant irritant/allergic reaction—stop and assess.
- Precautions: avoid eyes, lips, nostrils, mucosa, cuts, eczema and sunburn. Use sunscreen and non-comedogenic moisturiser. Discuss pregnancy or breastfeeding before use; do not self-start in pregnancy.
5.3 Tazarotene
Tazarotene is a third-generation prodrug converted in skin to tazarotenic acid, an RAR-selective agonist.
| Indication | Typical regimen | Important points |
|---|---|---|
| Plaque psoriasis | 0.05% or 0.1% cream/gel/foam: thin layer once nightly to plaques; start 0.05% when irritation risk is high and increase only if tolerated. | Protect surrounding normal skin with petrolatum; avoid large areas, skin folds and open/infected plaques unless prescribed. |
| Acne vulgaris | Usually 0.1% once nightly to the entire acne-prone area (some products start 0.05%); apply a thin film, approximately 2 mg/cm² for labelled cream products. | Use moisturiser and sunscreen. Burning and peeling are dose-limiting. |
Contraindication: pregnancy is a labelled contraindication because retinoid receptor agonism may cause fetal harm. Avoid in people trying to conceive unless a specialist provides an alternative plan. Avoid eyes/mucosa and do not occlude.
5.4 Alitretinoin
Alitretinoin (9-cis-retinoic acid) binds RAR and RXR. Topical gel is used in selected jurisdictions for cutaneous Kaposi sarcoma lesions; oral alitretinoin is a specialist option for severe chronic hand eczema in some countries.
- Topical Kaposi sarcoma regimen: apply a small amount to lesions twice daily, gradually increasing to three or four applications daily if tolerated. Do not apply to normal surrounding skin, mucosa or under an occlusive dressing. Exact dose is lesion- and product-dependent.
- Local toxicity: erythema, rash, pain, paresthesia, pruritus, exfoliative dermatitis and oedema. Reduce frequency or temporarily interrupt for severe inflammation.
- Systemic cautions: avoid pregnancy; minimise sunlight/UV exposure. Keep away from DEET-containing insect repellents on treated skin because increased irritation has been reported with some formulations.
6. Systemic retinoids: specialist medicines
6.1 Isotretinoin (13-cis-retinoic acid)
Best indication: severe recalcitrant nodular/nodulocystic acne, acne causing scarring or major psychological distress, and selected severe acne variants after appropriate antimicrobial and topical therapy. Specialist teams may also use it for gram-negative folliculitis, pyoderma faciale, severe rosacea or dissecting cellulitis. It targets all major acne drivers: sebaceous-gland activity, sebum, follicular keratinisation, Cutibacterium acnes environment and inflammation.
| Regimen | Dose | Notes |
|---|---|---|
| Start | Often 0.5 mg/kg/day orally | Lower starting doses reduce early flare and mucocutaneous toxicity. |
| Usual course | Increase toward 0.5–1 mg/kg/day in one or two divided doses for approximately 15–20 weeks; many protocols target a cumulative 120–150 mg/kg, adjusted to response and toxicity. | Very severe disease may require specialist doses up to 2 mg/kg/day, but toxicity rises substantially. |
| Acne fulminans/major inflammatory flare | Consider a lower isotretinoin dose with specialist-supervised prednisone, often about 0.5–1 mg/kg/day initially. | Urgently assess fever, arthralgia, ulceration and systemic involvement. |
| Low-dose rosacea regimens | Some specialists use about 10 mg/day for several months. | Off-label and product/jurisdiction dependent; use dermatology supervision. |
Administration: formulations differ in food requirements. Some standard capsules may be taken with or without meals, whereas lipid-dependent formulations require food. Follow the exact product label; swallow capsules whole and never share them.
Absolute safety priority: isotretinoin is a powerful human teratogen. It is contraindicated in pregnancy and must not be used when pregnancy is possible without a validated prevention and monitoring programme. Obtain documented pregnancy testing before starting and at the intervals required by the local programme; use two reliable forms of contraception when required, beginning at least one month before treatment and continuing during treatment and for at least one month after the last dose. Follow the current national pregnancy-prevention/dispensing system rather than relying on memory of an older programme.
Common adverse effects: cheilitis (about 96%), facial dermatitis, dry nose/epistaxis, dry skin, pruritus, desquamation, conjunctivitis, photosensitivity, headache, arthralgia/myalgia and reversible hair shedding. Lubricating lip balm, bland emollient, saline nasal gel and preservative-free artificial tears are useful supportive measures.
6.2 Acitretin
Acitretin is the active retinoic-acid metabolite of etretinate and is used mainly for severe psoriasis (including pustular and erythrodermic disease) and disorders of keratinisation. Its half-life is approximately 2–4 days, but ethanol can convert it back to etretinate, whose effective half-life is at least about 120 days.
| Clinical setting | Teaching regimen from specialist practice | Safety notes |
|---|---|---|
| Plaque psoriasis | Approximately 0.3–1.0 mg/kg/day; reassess after 4–6 weeks and expect fuller response over 3–4 months. | Use the lowest effective dose; combine with phototherapy only under supervision. |
| PUVA or UVB adjunct | About 0.3–0.5 mg/kg/day in specialist protocols. | Photosensitivity and burns can be amplified; phototherapy dose must be adjusted. |
| Erythrodermic psoriasis | Start near 0.3 mg/kg/day, cautiously increase toward 0.5–0.6 mg/kg/day if tolerated. | Admit/monitor unstable patients; treat fluid, temperature and infection risk separately. |
| Generalised pustular psoriasis | Some protocols start near 1 mg/kg/day, then reduce to 0.5–0.6 mg/kg/day over 3–6 months. | Specialist-only; evaluate systemic inflammation, electrolytes and infection. |
| Maintenance/keratinisation disorders | Low-dose long-term treatment may be used. | Review lipids, liver, bone/musculoskeletal symptoms and reproductive plans regularly. |
- Capsules and administration: common capsule strengths are 10 mg, 17.5 mg and 25 mg. Take once daily with the main meal or as the product label directs to improve absorption.
- Pregnancy: absolute contraindication. People who could become pregnant must use highly effective contraception during treatment and for at least three years after stopping (the exact national requirement must be checked). Do not donate blood during therapy and for the required post-treatment interval.
- Alcohol: avoid alcohol during treatment and for the post-treatment interval because ethanol can regenerate long-lived etretinate. This includes alcohol in drinks and potentially alcohol-containing medicines or supplements.
- Do not combine casually with methotrexate: hepatotoxicity may be additive. Benefit in psoriatic arthritis is not established; use a rheumatology plan.
6.3 Bexarotene
Bexarotene is a selective RXR agonist indicated for cutaneous T-cell lymphoma refractory to at least one prior systemic therapy.
- Starting dose: 300 mg/m² orally once daily with a meal. The 75-mg capsule must be swallowed whole; calculate body-surface area carefully.
- Escalation: if no tumour response after about 8 weeks and toxicity is acceptable, a specialist may increase to 400 mg/m²/day. Reduce to 200 mg/m², then 100 mg/m², or temporarily suspend for toxicity.
- Major toxicity: rapid, severe hypertriglyceridaemia and hypercholesterolaemia, pancreatitis, transaminase elevation, hypothyroidism, neutropenia and mucocutaneous dryness.
- Monitoring: fasting lipids at baseline and at least weekly until stable; thereafter approximately every 8 weeks (or more often if abnormal). Check liver tests at baseline and around weeks 1, 2 and 4, then at least every 8 weeks. Check TSH and free T4 at baseline and periodically; thyroid replacement is often required.
- Drug interactions: avoid gemfibrozil because it can markedly increase bexarotene exposure; review CYP3A4 inhibitors/inducers, lipid-lowering therapy and all supplements. Bexarotene may alter concentrations of other CYP-metabolised medicines.
- Pregnancy: contraindicated. Use the oncology programme’s pregnancy-testing and contraception requirements.
7. Adverse effects by body system
| System | Effects | Red flags requiring urgent assessment |
|---|---|---|
| Skin and mucosa | Dry lips, xerosis, peeling, erythema, dermatitis, pruritus, epistaxis, photosensitivity, hair thinning. | Blistering, widespread skin pain/sloughing, mucosal erosions, fever or suspected Stevens–Johnson syndrome. |
| Lipids | Raised triglycerides and cholesterol (especially isotretinoin/acitretin/bexarotene). | Triglycerides very high, abdominal pain/vomiting or lipaemic serum—possible pancreatitis. |
| Liver | Raised transaminases, fatty change or toxic hepatitis. | Jaundice, dark urine, right-upper-quadrant pain, marked enzyme rise or coagulopathy. |
| Neuro-ocular | Headache, dry eye, reduced night vision; rare benign intracranial hypertension (pseudotumour cerebri). | Severe persistent headache, vomiting, pulsatile tinnitus, diplopia, papilloedema or visual loss. |
| Musculoskeletal | Arthralgia, myalgia, back pain, hyperostosis/osteophytes with longer exposure; premature epiphyseal closure in growing children. | Severe weakness, inability to walk, fracture or new neurologic deficit. |
| Endocrine/haematologic | Bexarotene-related hypothyroidism; leukopenia/neutropenia; rare agranulocytosis. | Fever or infection with neutropenia, severe lethargy, cold intolerance or bradycardia. |
| Gastrointestinal | Nausea, abdominal discomfort; possible inflammatory bowel-disease flare is reported. | Severe abdominal pain, bloody diarrhoea or persistent vomiting. |
| Psychiatric | Mood change, anxiety or depression has been reported; causal association with isotretinoin remains debated. | Suicidal thoughts, psychosis or abrupt behavioural change: stop dispensing and obtain urgent mental-health assessment. |
8. Contraindications and high-risk situations
Systemic retinoids are contraindicated in pregnancy because of severe craniofacial, central-nervous-system, cardiovascular, auditory, ocular, skeletal and thymic abnormalities. Pregnancy prevention, testing, documentation, dispensing controls and post-treatment contraception are core pharmacology—not paperwork.
- Pregnancy, breastfeeding where the product label prohibits use, or inability/unwillingness to follow contraception and testing requirements.
- Significant hepatic or renal dysfunction, uncontrolled hyperlipidaemia, pancreatitis or unexplained persistent transaminase elevation.
- Concurrent vitamin-A supplements or another systemic retinoid.
- Concurrent tetracycline (pseudotumour-cerebri risk), unless a specialist has a compelling reason and monitoring plan.
- Known hypersensitivity to the product or excipients.
- For bexarotene: untreated hypothyroidism, uncontrolled lipid disorder, severe neutropenia or interacting medicines.
- For topical agents: acute sunburn, severe eczema, open wounds, mucosal surfaces or application to large areas without supervision.
9. Interactions that matter in exams and emergencies
| Combination | Risk | Action |
|---|---|---|
| Retinoid + vitamin-A supplement, cod-liver oil or another retinoid | Additive hypervitaminosis-A toxicity. | Stop non-essential supplement; reconcile every OTC product. |
| Isotretinoin/acitretin + tetracycline | Increased risk of intracranial hypertension. | Avoid combination; investigate headache/visual symptoms urgently. |
| Acitretin + ethanol | Reforms etretinate, prolonging reproductive risk. | No alcohol during therapy and for the required post-treatment interval. |
| Bexarotene + gemfibrozil | Markedly increases bexarotene concentration and toxicity. | Avoid; choose a specialist-approved lipid strategy. |
| Bexarotene + CYP3A4 inhibitor/inducer | Altered exposure and response. | Review antibiotics, azoles, anticonvulsants, macrolides, HIV medicines and herbal products. |
| Retinoid + methotrexate or other hepatotoxin | Additive liver injury. | Specialist decision, baseline and repeated liver tests. |
| Topical retinoid + benzoyl peroxide, sulfur, resorcinol, salicylic acid or abrasive products | Excess irritation, dermatitis and barrier failure. | Separate applications or use a formulated combination; simplify skincare if inflamed. |
| Retinoid + phototherapy/intense sun | Photosensitivity and burns. | Sun protection; reduce phototherapy dose under supervision. |
10. Monitoring protocol
Before systemic treatment
- Confirm diagnosis, severity, previous treatment and the indication for a systemic retinoid.
- Document pregnancy status and prevention plan where applicable; obtain baseline pregnancy test according to the local programme.
- Baseline full blood count, fasting lipid profile (including triglycerides), liver function tests and renal function as clinically appropriate.
- Record mental-health history, inflammatory bowel symptoms, headache/visual symptoms, musculoskeletal disease and all prescription/OTC medicines.
- For bexarotene: add TSH/free T4 and establish a lipid-lowering plan before the first dose.
During treatment
| Medicine | Minimum practical follow-up |
|---|---|
| Isotretinoin | Review monthly during initiation and dose changes; repeat pregnancy testing and required laboratory tests per programme. Recheck lipids/LFTs after about 4–6 weeks and after dose changes, then periodically. Ask about mood, headache/vision, abdominal pain, muscle symptoms and contraception at every visit. |
| Acitretin | Review clinically after 4–6 weeks, then at regular intervals; monitor lipids and LFTs, assess skeletal symptoms, alcohol exposure and reproductive plans. |
| Bexarotene | Fasting lipids at least weekly until stable; LFTs around weeks 1, 2 and 4, then at least every 8 weeks; TSH/free T4 regularly; CBC for neutropenia. Intensify monitoring after any dose or interacting-medicine change. |
| Topical retinoids | Clinical review at 6–12 weeks for acne and sooner for severe dermatitis, infection, pregnancy, ocular symptoms or suspected allergy. |
11. Emergency presentations and what to do
Pregnancy exposure
Stop systemic retinoid immediately, do not reassure falsely, document dose/date, contact dermatology/teratology and arrange urgent obstetric counselling. Do not advise termination; provide non-directive, specialist-led risk assessment.
Hypertriglyceridaemia/pancreatitis
Stop the suspected retinoid, check fasting triglycerides, lipase, glucose, electrolytes and liver tests; treat pancreatitis using local emergency protocols. Bexarotene can produce dramatic lipid rises early.
Pseudotumour cerebri
Severe headache, vomiting, transient visual obscurations, diplopia or papilloedema: stop retinoid and tetracycline, urgent ophthalmology/neurology review, neuroimaging and lumbar-puncture assessment when safe.
Severe mucocutaneous reaction
Fever, skin pain, blistering, epidermal detachment or mucosal erosions: stop drug, isolate from irritants and manage as a dermatologic emergency (possible SJS/TEN).
- Hepatotoxicity: stop or hold the retinoid for marked transaminase elevation or symptoms, exclude viral/ischemic/obstructive causes and involve the prescriber; assess INR if severe.
- Severe mood change: ask directly about suicidal thinking, ensure immediate safety and urgent mental-health assessment; do not leave the patient with further doses while risk is being assessed.
- Visual loss/night blindness: stop driving, avoid night work and obtain urgent ophthalmic review. Persistent symptoms may outlast treatment.
12. Clinical cases
Case 1 — isotretinoin and a positive pregnancy test
A 20-year-old taking isotretinoin reports a missed period and a positive home test. Stop isotretinoin immediately, verify pregnancy with an appropriate test, document the last dose, avoid further dispensing and urgently refer to dermatology and teratology/obstetric services. Explain that retinoid exposure carries fetal risk but that decisions about pregnancy must be made with specialist, non-directive counselling.
Case 2 — acitretin, alcohol and future pregnancy
A patient on acitretin drinks wine daily and wants to conceive in six months. Stop and urgently review: ethanol may convert acitretin to etretinate, extending the required contraception interval to at least three years after exposure. Counsel about alcohol-containing medicines, contraception and an alternative psoriasis plan.
Case 3 — bexarotene, triglycerides 1,200 mg/dL and abdominal pain
This is possible hypertriglyceridaemic pancreatitis. Withhold bexarotene, obtain urgent lipase, metabolic panel and abdominal assessment, begin pancreatitis management and involve oncology/endocrinology. Do not simply increase a lipid drug or continue bexarotene while waiting.
Case 4 — topical retinoid burn
A student applies tretinoin, salicylic acid, a scrub and benzoyl peroxide several times daily, then develops painful erythema and peeling. Stop irritants, use bland moisturiser and sunscreen, treat secondary infection only if present, and restart one evidence-based product slowly after the barrier heals.
Case 5 — headache while taking isotretinoin and doxycycline
Severe headache with vomiting or visual symptoms is an emergency. Stop both medicines and arrange urgent neurologic/ophthalmic assessment for intracranial hypertension. Do not treat repeatedly with analgesia without examining the optic discs and visual function.
13. Practical prescribing checklist
- Confirm indication, severity and treatment alternatives.
- Choose topical versus systemic therapy and document the exact product strength.
- Check pregnancy risk, contraception, baseline lipids, liver function and interacting medicines before systemic therapy.
- Give written application instructions: pea-sized thin film, entire affected area, night use, moisturiser and sunscreen; never apply more often to speed results.
- Explain expected early dryness/flare and the red flags that require urgent review.
- Set a dated review and laboratory plan; do not issue unmonitored repeat prescriptions for systemic retinoids.
- Record counselling about sharing medicine, blood donation, alcohol (acitretin), vitamin-A supplements, tetracyclines and safe storage away from children.
14. High-yield examination points
- RAR/RXR heterodimers bind RAREs and alter gene transcription; AP-1 inhibition contributes to anti-inflammatory effects.
- Isotretinoin is 13-cis-retinoic acid and the most potent sebaceous suppressant in clinical use.
- Acitretin plus ethanol can regenerate etretinate, creating a very prolonged reproductive precaution.
- Bexarotene is RXR-selective: think CTCL, severe hypertriglyceridaemia and hypothyroidism.
- Tretinoin, adapalene and tazarotene are usually applied once nightly to the whole affected area, not as spot therapy.
- Topical irritation is managed by less frequent application and barrier support; systemic toxicity requires withholding the drug and targeted assessment.
- Severe headache/visual change on a retinoid—especially with tetracycline—is possible intracranial hypertension until proven otherwise.
- All systemic retinoids are specialist medicines with strict pregnancy prevention; never rely on a single negative test or verbal reassurance.
15. Sources and further reading
- Retinoids — supplied SlideShare teaching deck.
- DailyMed: isotretinoin capsule prescribing information.
- DailyMed: acitretin capsules.
- DailyMed: adapalene gel 0.3%.
- DailyMed: tazarotene topical products.
- DailyMed: bexarotene capsules.
- DailyMed: alitretinoin topical gel.
- DailyMed: tretinoin topical preparations.
This resource supports learning and supervised clinical reasoning. Doses, pregnancy-prevention rules, formulations and monitoring intervals can vary by country and product. In real practice, verify the current local formulary, licensed product information and specialist protocol before prescribing or dispensing any retinoid.
