Mechanism of action
- Modulation of epidermal proliferation.
- Induction of orthokeratosis.
- Comedolysis.
- Inhibition of inflammation.
- Inhibition of sebum secretion.
- Anticarcinogenic effects.
Indications
- Severe psoriasis that cannot be managed by topical treatments or photo(chemo)therapy
- Monotherapy is indicated for erythrodermic or pustular psoriasis.
- Combination therapy is indicated for chronic plaque psoriasis .
- Lichen planus : 30 mg/day for 8 weeks.
- Morphea.
- Macular or lichen amyloidosis : 0.5 mg/kg/day.
- Lipoid proteinosis : 0.5 mg/kg/day for 6 months.
- Collodion baby.
- Harlequin ichthyosis : 1 mg/kg/day.
- Erythrokeratoderma.
- Keratoderma.
- Ichthyoses : 1 mg/kg /day.
- Lupus erythematosus : 50 mg daily + hydroxychloroquine 400 mg daily for 8 weeks.
- Darier disease : 10-25 mg /day.
- Nail psoriasis: 0.2–0.3 mg/kg/day.
- Perforating diseases.
- Chronic hand eczema.
- Chemoprevention of skin cancer : 0.2–0.4 mg/kg/day.
Dosage
- Start with 10 mg/day increase up to 25–50 mg/day.
Monitoring
Baseline
- History to exclude contraindications.
- Pregnancy test (when indicated).
- Complete blood count.
- Liver function tests (AST, ALT, GGT, alkaline phosphatase, bilirubin).
- Fasting Serum triglycerides, cholesterol.
- Fasting glucose.
- Serum creatinine.
- Consider spinal X-ray (often initially performed during the first 3 months of therapy if long-term treatment is anticipated).
Follow up
- Monitor mucocutaneous side effects.
- liver function tests and fasting cholesterol & triglycerides every 4 weeks for the first 2 months of then every 3 -6 months.
- Serum creatinine (elderly patients or patients with mild to moderate renal dysfunction).
- Monitor for development of hyperostosis by history (twice yearly) and by X-ray of spine (e.g. once yearly or every other year in patients receiving long-term treatment).
Side effects
- Teratogenic.
- Cheilitis, dryness of the oral and nasal mucosa, xerosis, pruritus and skin fragility.
- Delayed wound healing.
- Formation of excessive granulation tissue
- Hypertriglyceridemia
- Hyperostosis ( Long-term treatment ).
- Myalgias, Arthralgia.
- Back pain.
- Vulvovaginitis.
- Paronychia.
- Increased insulin sensitivity.
- Elevation of serum creatine kinase levels.
- Eyes : Blepharitis, conjunctivitis, xerophthalmia, night blindness.
- Liver: occasionally elevated transaminases.
Drug interactions
- Tetracycline, doxycycline, minocycline : may increase intracranial pressure (Pseudotumor cerebri).
- Alcohol : increased conversion of acitretin to etretinate and hepatotoxicity.
- Methotrexate : synergistic liver toxicity with retinoids; however, combination may be used with caution in patients with PRP or severe psoriasis.
- vitamin A supplements : risk of hypervitaminosis A.
- Retinoid drug levels and resultant potential for toxicity may increase with CYP3A4 inhibitors such as azoles and macrolides.
- Antituberculosis drugs (rifampin) and anticonvulsants (phenytoin and carbamazepine) may decrease the drug levels of retinoids via CYP3A4 induction.
- Retinoids may also increase the drug levels of cyclosporine.
- Progesterone pills (minipill) preparations : Acitretin decreases the antiovulatory effect of the progestin only pill (mini-pill) but has no effect on the combined preparations.
- Antidiabetic agents : Alterations in blood glucose may occur
- Corticosteroids : Hyperlipidemia, pseudotumor cerebri.
Pregnancy and lactation
- Category X.
- Mothers receiving acitretin should not breast-feed.
Precautions
- When acitretin is added to UV, light dose should be reduced by 30-50%.
- In children on long-term therapy growth charting and annual screening radiography is advisable.
- Patients should not donate blood during treatment or for at least 6 months after stoppage.
- pregnancy should be avoided for the duration of therapy and for 3 years after.
Drug info
- Its bioavailability is increased by intake with fatty food.
- Alcohol indirectly increases the conversion of acitretin to etretinate by acting as a catalyst for hepatic enzymes.
- It can be used for psoriasis associated with human immunodeficiency virus (HIV) infection.
#Acitretin #Oral retenoids