|
 Supirocin Ointment
COMPOSITION
Mupirocin USP 2%
Water soluble base q.s.
DESCRIPTION
White semi-solid ointment packed in aluminium tubes or plastic jar.
THERAPEUTIC CLASS
T0110
PHARMACOLOGY
Mechanism of action
Mupirocin (pseudomonic acid; pseudomonic acid A) is an antibiotic produced
by submerged fermentation of Pseudomonas fluorescens and is structurally
unrelated to other antibiotics. Other substances produced by Pseudomonas
fluorescens which are being investigated for antibacterial activity
include pseudomonic acids B, C, and D. However, mupirocin appears to have
the most antibacterial activity. Pseudomonic acids B, C, and D are generally
2 to 4-fold less active than pseudomonic acid A (mupirocin).
The mechanism of action of mupirocin is unique in that it reversibly and
specifically binds to bacterial isoleucyl transfer-RNA synthetase resulting
in arrest of protein synthesis, a mechanism dissimilar from any other
antibiotic, and inhibiting RNA synthesis. This mechanism of action
presumably accounts for the slow rate of emergence of mupirocinresistant
staphylococci observed in in vitro studies and lack of cross-resistance with
other topical antibiotics. The drug has been active against multi-resistant
strains of Staphylococcus aureus and coagulase-negative
staphylococci, including strains resistant to penicillin, methicillin,
neomycin, erythromycin, fusidic acid, lincomycin, chloramphenicol,
tetracycline and gentamicin.
Mupirocin enters cells by passive diffusion. The concentration of mupirocin
in sensitive bacteria is dependent upon binding sites on isoleucyl-tRNA
synthetase. Resistance to mupirocin involve restricted access to the binding
site on isoleucyl-tRNA synthetase as opposed to changes in the cell
membrane.
Mupirocin is used for the topical treatment of impetigo due to
Staphylococcus aureus; Group A beta-hemolytic Streptococcus, and
Streptococcus pyogenes.
Antimicrobial spectrum
Based on in vitro studies, mupirocin has a broad range of
antibacterial activity. Grampositive bacteria sensitive to mupirocin include
Staphylococcus aureus (including methicillin-resistant and beta-lactamase
producing), Staphylococcus epidermis, Staphylococcus saprophyticus, and
Streptococcus pyogenes. Gram-negative bacteria sensitive to mupirocin
include H influenzae, N gonorrhoeae, N meningitidis, Bordetella pertussis,
Pasteurella multocida and M catarrhalis (Minimum inhibitory concentration
(MIC) less than or equal to 0.25 mg/L). The drug has also been active in
vitro against methicillinresistant S. aureus that is resistant to
gentamicin.
Mupirocin is bactericidal at concentrations achieved by topical
administration. However, the minimum bactericidal concentration (MBC)
against relevant pathogens is generally eightfold to thirty-fold higher than
the minimum inhibitory concentration (MIC). In addition, mupirocin is highly
protein bound (>97%), and the effect of wound secretions on the MICs of
mupirocin has not been determined.
Resistance occurs rarely. However, when mupirocin resistance does occur, it
appears to result from the production of a modified isoleucyl-tRNA
synthetase. High-level plasmidmediated resistance (MIC >1024 mcg/mL) has
been reported in some strains of S. aureus and coagulase-negative
staphylococci. Due to this unique mode of action, mupirocin demonstrates no
in vitro cross-resistance with other classes of antimicrobial agents.
Pharmacokinetics
The bioavailability of a topical mupirocin formulation is very low (0.24%).
Penetration of mupirocin is enhanced if occlusive dressing is used or if
mupirocin is applied to damaged or diseased skin. Measurable radioactivity
was present in the stratum corneum of these subjects 72 hours after
application. Mupirocin is slowly metabolized in the skin to an inactive
metabolite, monic acid. Only 2.7% of mupirocin is metabolized in 48 hours in
homogenates of human skin.
INDICATIONS
Supirocin Ointment is indicated for the bacterial skin infections e.g:
impetigo, folliculitis and furunculitis.
CONTRAINDICATIONS
Hypersensitivity to mupirocin or to any components in the formulation.
SIDE EFFECTS/ ADVERSE REACTIONS
Adverse reactions are listed below by system organ class and frequency.
Frequencies are defined as: very common (1/10), common (1/100, <1/10),
uncommon (1/1000, <1/100), rare (1/10,000, <1/1000), very rare (<1/10,000),
including isolated reports. Very rare adverse reactions were primarily
determined from post-marketing experience data and therefore refer to
reporting rate rather than true frequency.
Skin and subcutaneous tissue disorders:
Common: Burning localised to the area of application.
Uncommon: Itching, erythema, stinging and dryness localised to the area of
application. Uncommon: Cutaneous sensitisation reactions to mupirocin or the
ointment base.
Immune system disorders:
Very rare: Systemic allergic reactions have been reported with Mupirocin
Ointment.
PRECAUTIONS / WARNINGS
• Formulations containing polyethylene glycol should not be applied to
broken skin or mucus membranes, extensive open wounds or to burns.
• Formulations containing polyethylene glycol should not be used in patients
with moderate or severe renal impairment; absorption of polyethylene glycol
is possible.
• Avoid contact with eyes.
• As with other antibacterial products, prolonged use may result in
overgrowth of non susceptible organisms, including fungi.
DRUG INTERACTION
The effect of the concurrent application of Mupirocin ointment and other
drug products has not been studied.
USE IN PREGNANCY AND LACTATION
Pregnancy
Pregnancy Category B
Animal studies using doses that exceed the recommended human dose
demonstrated that mupirocin is not teratogenic. However, there are no
well-controlled studies in pregnant women. Animal teratogenicity studies are
not always predictive of human response. Mupirocin should be used during
pregnancy only if the drug is clearly needed.
Lactation
It is unknown if mupirocin is excreted in human milk; caution should be used
when mupirocin is administered to a nursing woman.
RECOMMENDED DOSAGE, DOSAGE SCHEDULE AND ROUTE OF ADMINISTRATION
Adults and children:
Supirocin Ointment should be applied to the affected area up to three times
daily, for up to 10 days. The area may be covered with a dressing or
occluded if desired.
Route of administration : Topical
SYMPTOMS AND TREATMENT FOR OVERDOSAGE AND ANTIDOTE (S)
No overdosage has been reported with mupirocin ointment. Since systemic
absorption of mupirocin ointment is very low, overdosage is less likely with
mupirocin ointment.
PRESENTATION 5g and 15g tube 50g jar pack
SHELF LIFE 24 months
STORAGE CONDITIONS, USER INSTRUCTIONS AND PHARMACEUTICAL PRECAUTIONS
Store below 25°C. Do not freeze.
|
