Smith & Nephew
Action And Clinical Pharmacology: Silver sulfadiazine is released slowly from the cream, and thus rapid depletion of chloride and associated electrolyte disturbances are minimized. Silver sulfadiazine is not inhibited by PABA.
In burned pigs, the absorption of silver was less than 1% of the applied dose, however 5 to 8% of the sulfadiazine was absorbed. There is very little penetration of the silver below the outer layers of the wound surface, and the largest amount of the absorbed silver is found in the liver. In addition, high concentrations of silver have been measured in the bile, which suggest a hepatobiliary excretion of the silver moiety. The sulfadiazine moiety is excreted via the kidneys.
After a 500 to 1 000 g application of 1% silver sulfadiazine, (corresponding to 5 to 10 g of silver sulfadiazine), to burn patients, serum levels of sulfadiazine were 2 to 5 mg/L, and the urine levels were 60 to 1 000 mg/L. The daily urinary excretion of sulfadiazine was 100 to 200 mg, corresponding to less than 5% of the applied amount of silver sulfadiazine.
The sulfadiazine concentration in burn wound exudates, was 900 to 1 000 mg/L 24 hours after application, which is approximately 20 times the MIC of sensitive bacteria (50 mg/L).
In one study of 23 patients, mean silver serum levels were moderately higher than the normal range however the urinary excretion of silver, was markedly elevated (0.402 mg/24h). The 6 patients with 60% or greater B.S.A. burns had a mean peak excretion of 1.100 mg/24 hours (approximately 1 000 times the normal level). None of the patients had silver toxicity.
Indications And Clinical Uses: For the treatment of leg ulcers, burns, skin grafts, incisions and other clean lesions, abrasions, minor cuts and wounds.
Silver sulfadiazine is especially indicated in the treatment and prophylaxis of infection in serious burn victims.
Contra-Indications: Sulfonamide therapy is known to increase the possibility of kernicterus. Silver sulfadiazine should not be used in pregnant females at term, in premature infants, or in newborn infants during the first month of life.
The product should not be used on patients with a known sensitivity to any of its components.
Manufacturers’ Warnings In Clinical States: Sensitization to topically applied silver sulfadiazine is rarely predicted or proven by patch testing. Caution should be exercised in the use of silver sulfadiazine in individuals who have previously shown sensitization reactions to sulfonamides.
Silver sulfadiazine should be used with caution on patients with a history of G-6-PD deficiency as hemolysis may occur.
When treatment with silver sulfadiazine involves prolonged administration and/or large burned surfaces, considerable amounts of silver sulfadiazine are absorbed. Serum concentration of silver sulfadiazine may approach adult therapeutic levels (8 to 12 mg%).
Precautions: Silver sulfadiazine should be used with caution in patients with significant hepatic or renal impairment.
Leukopenia has been reported following the use of silver sulfadiazine, especially on patients with large area burns. This may be a drug-related effect, and often occurs 2 to 3 days after treatment has commenced. It is usually self-limiting and therapy with silver sulfadiazine does not normally need to be discontinued, as the WBC count usually returns to the normal range in a few days. WBC counts should be closely monitored.
Pregnancy: The safe use of silver sulfadiazine has not been established in pregnancy. Silver sulfadiazine should only be used in badly burned pregnant women if the benefit to the patient outweighs the risk to the fetus. Silver sulfadiazine should not be used when the patient is near term (see Contraindications).
Drug Interactions: Enzymatic Debriding Agents: Silver sulfadiazine may inactivate enzymatic debriding agents, thus the concomitant use of these compounds may be inappropriate.
Oral Hypoglycemic Agents and Phenytoin: In patients with large area burns where serum sulfadiazine levels may approach therapeutic levels, the action of oral hypoglycemic agents and phenytoin may be potentiated and it is recommended that blood levels be monitored.
Cimetidine: In patients with large area burns, it has been reported that co-administration of cimetidine may increase the incidence of leukopenia.
Adverse Reactions: Leukopenia: In patients with large area burns, silver sulfadiazine treatment has been reported to have caused a rash in 2 to 5% of patients. Moderate, and usually transient leukopenia has been reported in up to 3 to 5% of patients and occurs within 48 to 72 hours after therapy has commenced, and generally occurs in patients with at least 30% burns. It is usually self-limiting and the leukocyte count is normalized within 2 to 3 days regardless of whether treatment with silver sulfadiazine is continued or terminated.
Caution should be exercised in individuals who have previously shown a sensitization to sulfonamides, however sensitization to topically applied silver sulfadiazine is rarely predicted or proven by patch testing.
Sulfonamide: During the treatment of burns over large body surfaces (greater than 20% body surface area), significant amounts of SSD are systematically absorbed. Therefore, it is possible that any adverse reactions associated with sulfonamides may occur.
Symptoms And Treatment Of Overdose: Symptoms and Treatment: In extensively burned patients or in patients suspected of showing symptoms of excessive absorption, it is important to optimally maintain fluid balance not only to prevent dehydration but also to avoid the possibility of renal impairment.
Dosage And Administration: Burns: The burn wounds should be cleaned and silver sulfadiazine applied over all the affected areas to a depth of 3 to 5 mm.
One technique is to apply the cream with a sterile gloved hand and/or sterile non metallic spatula. Where necessary, the cream should be re-applied to any area from which it has been removed by patient activity.
The cream should be re-applied at least every 24 hours.
Hand burns and finger injuries: One recommended method which has been found successful is to apply silver sulfadiazine to the burn and the whole hand is then enclosed in a clear plastic bag or glove, which is then closed at the wrist. The patient should be encouraged to move the hand and fingers. The dressing should be changed every 3 days or when an excessive amount of exudate has accumulated in the bag.
Leg Ulcers: One acceptable method involves filling the cavity of the ulcer with silver sulfadiazine to a depth of at least 3 to 5 mm. Care should be taken to prevent the spread of the cream onto non-ulcerated areas. The cream should be followed by an absorbent pad or gauze dressing, with further application of pressure bandaging as appropriate for the ulcer. The dressing should be changed every 2 or 3 days, with cleaning and debriding being performed before application of silver sulfadiazine.
It is not recommended that silver sulfadiazine be used in leg ulcers that are very exudative.
A container of silver sulfadiazine should be reserved for use for a specific patient and should be discarded when no longer required.
Availability And Storage: Each g of cream contains: silver sulfadiazine 1% w/w. Sterile jars of 500 g and sterile tubes of 50 and 30 g. Store at 15 to 20°C. Discard cream which has darkened.
FLAMAZINE® Smith & Nephew Silver Sulfadiazine Topical Antibacterial
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