| PRINCIPLES OF PRESCRIBING TOPICAL PREPARATIONS AND TOPICAL STEROIDS
1. GENERAL PRINCIPLES
1.1 For all topical drugs, choose the active ingredient coupled with an appropriate vehicle or base that suits the dermatological condition best.
1.2 A sufficient but not excessive quantity should be prescribed. For an adult, 30 g (to 33 g) = 1 oz cream or ointment is required for an application to cover the whole body surface once which comprises of :
3 g for head and face
3 g for an arm
6 g for a leg
9-12 g for the trunk
A thin smear twice daily is generally sufficient.
1.3 Drugs prescribed should be effective and not exceed the patient's economic limit.
1.4 Clear simple-to-follow instructions must be given to the patient concerning the frequency and quantity of application. A concise explanation on the mechanism of action and side effects of the prescribed drug often improves patient's trust on the doctor.
1.5 Choose a topical antibiotic that have high antibacterial activity, low allergenicity; and preferably it should be available only as a topical medicament. Avoid prolonged use of topical antibiotics, as this may induce bacterial resistance and increase risk of hypersensitivity reaction. If treatment involves a large area of the skin, choose a systemic antibiotic that fits the sensitivity test.
2. PRINCIPLES OF PRESCRIBING TOPICAL STEROIDS
Since 1950s, topical steroids have established a new milestone in dermatological therapeutics. However, its widespread misuse has led to considerable side effects which astonished physicians and patients alike. Some guidelines on prescribing topical steroids are discussed :
2.1 Do not prescribe steroids unless the diagnosis is reasonably certain. Corticosteroids are suppressive to all types of inflammations and are a sophisticated form of symptomatic treatment. Whenever they are used to treat skin disease, the dermatologist must exert further thoughts about treating the underlying disorder. Occasionally, when application ceases, the underlying disorder may return with increased vigour.
2.2 For a dermatological condition anticipating steroid treatment, any co-existing infection should be treated promptly. For example, in the treatment of atopic eczema with secondary infection, a short course of systemic +- topical antibiotics should be prescribed alongside with a topical steroid.
2.3 Use the topical steroid that is just sufficiently potent to control the skin condition in order to avoid significant local and systemic side effects. To facilitate better understanding of steroid potency, Tables 1 and 2 depicted the Classification of steroid according to their potency and Choice of steroid class by diseases and sites.
2.4 Avoid use of strong steroids on the face, flexures, scrotum; infants and young children with strong steroids as far as possible. The skins in these situations are thin (with a proportionally larger surface area as well) and are susceptible to atrophy as well as systemic absorption (discussed earlier). The use of strong steroids on face to control scarring of discoid lupus erythematosus is an exception.
2.5 In some situations, a potent topical steroid can be used initially (e.g., Dermovate 25-50 gm for 7 days) to gain rapid control then switching to a weaker steroid for maintenance later. Close supervision by the clinician is required. A rebound worsening of the skin condition should be prevented by avoiding sudden cessation of steroid treatment.
2.6 Generous use of emollients such as aqueous cream and emulsifying ointments can help to reduce the need for topical steroid. They are useful in regular caring of aging skin, and alleviating dryness-induced itchiness in dermatologic conditions such as ichthyosis and atopic dermatitis.
2.7 Clinicians should bear precautions when they attempt to dilute or mix topical steroid with other agents.
Potential problems include :
2.7.1 Inactivation of the active ingredients by the use of incompatible diluents, e.g., a mixture of Synalar and aureomycin ointment should be used as soon as the two ingredients mixed together, as the potency deteriorates within a short period of time.
2.7.2. Risk of bacterial contamination during dilution.
2.7.3 Amateurish mixing may produce varied concentrations in different portions of the same mixture and their efficacy affected.
For detailed techniques on drug mixing, an experienced pharmacist should be consulted.
Table 1 : Classification of Topical Steroid according to Potency Potency Steroid Trade Name (examples)
Mild 1% Hydrocortisone Efcortelan Acetate
0.05% Alcometasone Perderm Dipropionate
Moderate 0.05% Clobetasone Eumovate Butyrate
0.02% Triamcinolone 0.02% Aristocort A Acetonide
0.005% Fluocinolone 1/5 Synalar Acetonide
Potent 0.025% Beclomethasone Propaderm Dipropionate
0.05% Betamethasone Diprosone Dipropionate
0.1% Betamethasone Betnovate Valerate
0.025% Fluocinolone Synalar Acetonide
0.1% Hydrocortisone Locoid 17-Butyrate
0.05% Halometasone Sicorten Monohydrate
0.1% Diflucortolone Nerisone Valerate
Very Potent 0.05% Clobetasol Dermovate Propionate
0.1% Halcinonide Halog Table 2 : Choice of Steroid Class by Disease & Sites
Potency Class Diseases / Sites
Mild Eczema on the face
Flexural eczema on baby
Moderate Atopic eczema elsewhere especially in children and in flexures
Potent Lichenified atopic eczema
Discoid eczema
Seborrhoeic eczema of the trunk
Psoriasis
Very Potent Lichen simplex
Discoid eczema
Eczema & psoriasis of palms and soles
Lichen planus
Alopecia areata
Keloid
Discoid lupus erythematosus
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