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Retin-A: Product
Information
RETIN-A
Tretinoin
Presentation
Cream: 0.05%:
smooth, pale yellow, hydrophilic vehicle of polyoxyl 40
stearate, stearyl alcohol, stearic acid, isopropyl myristate,
butylated hydroxytoluene, sorbic acid and xanthan gum.
Actions
Animal studies
suggest that retinoic acid (tretinoin) is the tissue active
metabolite of Vitamin A, and has been designated 'partial
Vitamin A' in that it can stimulate the growth of Vitamin A
deficient animals but it is unable to correct defective vision
or impaired reproduction.
The therapeutic
action of tretinoin on acne skin is unrelated to its
physiological functions as a vitamin. The general effect is
that the proliferative activity of epidermal cells is greatly
enhanced, associated with changes in cellular differentiation
(keratinisation and cornification), resulting in diminished
keratinisation.
Absorption
studies carried out on the intact skin of the forearm in the
human have illustrated that only low sub-physiological dosing
of Vitamin A occurs when tretinoin is applied to the skin. It
is likely that absorption may be considerably increased when
tretinoin is applied repeatedly to acne skin.
Indications
RETIN-A
tretinoin Cream is indicated for topical
application in the treatment of acne vulgaris, primary grades
I-III in which comedones, papules and pustules predominate.
They are not recommended as mono-therapy in cases of severe
pustular and deep cystic nodular varieties (acne
conglobata).
Dosage
and Administration
RETIN-A Cream
should be applied once a day, before retiring, to the skin
where acne lesions appear, using enough to cover the entire
affected area lightly.
During the early
weeks of therapy, an apparent exacerbation of inflammatory
lesions may occur. This is due to the action of the medication
in deep, previously unseen lesions and should not be
considered a reason to discontinue therapy.
Therapeutic
results should be noticed after two to three weeks, but more
than 6 weeks of therapy may be required before definite
beneficial effects are seen. Once the acne lesions have
responded satisfactorily, it may be possible to maintain the
improvement with less frequent applications, or other dosage
forms.
Contraindications
Use of the
product should be discontinued if hypersensitivity to any of
the ingredients is noted.Warnings and Precautions
Warnings
Exposure to sunlight,
including sunlamps, should be minimised during the use of
RETIN-A, and patients with sunburn should be advised not to
use the product until fully recovered because of heightened
susceptibility to sunlight as a result of the use of
tretinoin.
Patients who may be
required to have considerable sun exposure due to occupation
and those with inherent sensitivity to the sun should exercise
particular caution. Use of sunscreen products and protective
clothing over treated areas is recommended when exposure
cannot be avoided.
Weather extremes such
as wind or cold, also may be irritating to patients under
treatment with tretinoin.
Medicated or abrasive
soaps and cleansers, soaps and cosmetics that have a strong
drying effect, and products with high concentration of
alcohol, astringents, spices, or lime should be used with
caution because of possible interaction with
tretinoin.
RETIN-A should be
kept out of the eyes, the mouth, angles of the nose and mucous
membranes.
If medication
is applied excessively, no more rapid or better results will
be obtained and marked redness, peeling, or discomfort may
occur.
Precautions
Use in
Pregnancy and Lactation:
Reproduction studies
performed in rats and rabbits at dermal doses up to 50 times
the human dose (assuming the human dose to be 1000mg of cream
or 500mg of gel per day) have revealed no evidence of impaired
fertility or harm to the foetus due to tretinoin.
There was however, a
slightly higher incidence of irregularly contoured or
partially ossified skull bones in some rat and rabbit
foetuses. There are no adequate and well-controlled studies in
pregnant women. Because animal reproduction studies are not
always predictive of human response, this drug should not be
used by pregnant women or those planning to become pregnant
during treatment.
It is not known
whether this drug is excreted in human milk. Because many
drugs are excreted in human milk caution should be exercised
when RETIN-A is administered to a nursing
mother.
Carcinogenicity
Photo
carcinogenicity studies in hairless albino mice have given
conflicting results. Some studies show acceleration, some
inhibition and others no effect on the tumorigenic potential
of ultra-violet radiation. Topical administration of tretinoin
in the absence of ultraviolet radiation showed no indication
of tumorigenicity. Although the significance to man is not
clear, patients should avoid or minimise exposure to sun.
Adverse Effects
RETIN-A (tretinoin)
acne treatment should be kept away from the eyes, the mouth,
angles of the nose, and mucous membranes. Topical use may
induce severe local erythema and peeling at the site of
application.
If the degree of
local irritation warrants, patients should be directed to use
the medication less frequently, discontinue use temporarily,
or discontinue use altogether.
Tretinoin has been
reported to cause severe irritation on eczematous skin and
should be used with utmost caution in patients with this
condition.
The skin of certain
sensitive individuals may become excessively red, oedematous,
blistered, or crusted.
If these effects
occur, the medication should be discontinued until the
integrity of the skin is restored, or the medication should be
adjusted to a level the patient can tolerate.
True contact allergy
to topical tretinoin is rarely encountered. Temporary hyper-
or hypopigmentation has been reported with repeated
application of RETIN-A. Some individuals have been reported to
have heightened susceptibility to sunlight while under
treatment with RETIN-A.
To date, all
adverse effects of RETIN-A have been reversible upon
discontinuance of therapy.Interactions
Concomitant topical
medication should be used with caution because of possible
interaction with tretinoin. Particular caution should be
exercised in using preparations containing peeling agents
(such as sulphur, resorcinol, or salicylic acid) with RETIN-A.
It also is advisable to "rest" a patient's skin until the
effects of peeling agents subside before use of RETIN-A is
started.
Overdosage
RETIN-A is indicated
for topical use only. If used excessively, no more rapid or
better results will be obtained and marked redness, peeling or
discomfort may occur. Oral ingestion of the drug may lead to
the same side effects as those associated with excessive oral
intake of vitamin A.
Medicine Classification
Prescription
medicine.
Package Quantities
Cream 0.05%
20g
Pharmaceutical Precautions
All RETIN-A topical
preparations should be stored below 25°C
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