1. Name Of The Medicinal Product
Sulfadiazine 500mg Tablets BP
2. Qualitative And Quantitative Composition
Sulfadiazine 500mg
3. Pharmaceutical Form
Tablet
Sulfadiazine tablets are plain white, biconvex tablets, with CP on one face.
4. Clinical Particulars
4.1 Therapeutic Indications
Sulfadiazine is a short-acting sulphonamide with bacteriostatic activity against a broad spectrum of organisms.
Gram-positive cocci - particularly group A Streptococci and some strains of Streptococcus pneumoniae, Bacillus anthracis, Nocardia (especially N.asteroides) and, to a lesser extent, Staphylococci and Clostridium perfringens.
Gram-negative cocci–Haemophilus influenzae and H.ducreyi are often sensitive, sensitivity varies among the enterobacteriae-Escherichia coli, Klebsiella, proteus, Salmonella and Serratia and Vibrio cholerae are sometimes sensitive. Other organisms reported to be sensitive include, Actinomyces spP., Brucella, Calymmatobacterium granulomatis, Legionella, Yersinia pestis, Chlamydia, Pseudomonas pseudomallei.
4.2 Posology And Method Of Administration
For oral administration.
Adults and elderly
The initial dose is usually 2-4 grams followed by a maintenance dose of up to 4 grams daily in divided doses for a maximum of seven days.
Dosage reduction may be necessary in renal impairment.
Children
Initially 75mg/kg, followed by a maintenance dose of 150mg/kg daily in divided doses. Maximum of 6 grams daily.
Sulphonamides should not be used for initial treatment of meningococcal meningitis although oral sulfadiazine may be substituted for parenteral penicillin once susceptibility to sulphonamides has been established.
4.3 Contraindications
Known hypersensitivity to any sulphonamide.
Severe renal or hepatic failure.
Acute porphyria.
Jaundice or blood disorders.
Neonates.
4.4 Special Warnings And Precautions For Use
Caution in elderly, renal or hepatic impairment. Reactions are more likely in acquired immune deficiency syndrome, lupus erythematosus, glucose-6-phosphate dehydrogenase deficiency or history of allergy or asthma. Treatment with a sulphonamide should be discontinued immediately a rash appears because of the danger of severe allergic reactions such as Stevens-Johnson syndrome, although this reaction is less common with sulfadiazine. A high fluid intake (5-6 pints in 24 hours) should be maintained, and urinary output should be rendered alkaline to prevent crystallisation of acetyl sulfadiazine. During prolonged treatment, regular examinations of the blood should be made.
4.5 Interaction With Other Medicinal Products And Other Forms Of Interaction
Like other sulphonamides, sulfadiazine demonstrated synergy with the difolate reductase release inhibitors, pyrimethamine and trimethoprim. The antidiabetic effect of sulphonylureas may be enhanced. Sulphonamides may potentiate the effect of anticoagulants, thiazide diuretics, methotrexate, phenytoin, chlorpropramide, tolbutamide and some uricosuric agents. Sulphonamides are displaced by indomethacin, salicylates and probenecid. The above interactions are theoretical and unlikely to be clinically significant. The antibacterial activity of sulphonamides may be antagonised by local anaesthetics or para amino benzoic acid.
4.6 Pregnancy And Lactation
There is epidemiological evidence of the safety of sulfadiazine in human pregnancy, but the clinician should assess the risk benefit factors before recommending sulfadiazine to pregnant women. There is evidence of embryotoxicity and teratogenicity in animals at high dosage, especially during the first trimester. It is generally considered that sulphonamides are not given late in pregnancy because of the risk of kernicterus in the newborn.
Sulphonamides are excreted in the breast milk in small amounts and should be used with extreme caution in nursing mothers because of the risk of kernicterus in the newborn.
4.7 Effects On Ability To Drive And Use Machines
Not known.
4.8 Undesirable Effects
These are common to all sulphonamides and more likely in slow acetylators.
Most commonly, nausea, anorexia, vomiting, diarrhoea.
Hypersensitivity reactions may take the form of fever, rashes, photosensitivity, exfoliative dermatitis, toxic epidermal, necrolysis, erythema nodosum, Stevens-Johnson syndrome, contact dermatitis, systemic lupus erythematosus, serum sickness like syndrome, liver necrosis, hepatomegaly, jaundice, myocarditis, pancreatitis, pulmonary eosinophilia, fibrosing alveolitis, vasculitis, nephrotoxic reactions (interstitial nephritis, tubular necrosis) may result in renal failure. Occasional blood disorders include, agranulocytosis, aplastic anaemia, thrombocytopenia, leucopenia, hypoprothrombinaemia, eosinophilia; rarely, acute haemolytic anaemia (with glucose-6-phosphate dehydrogenase deficiency). Anaphylaxis is very rare.
Crystalluria may occur, with lumbar pain, haematuria, oliguria and anuria. Reduce risk by high fluid intake. Treat by alkalinisation of urine.
Other adverse reactions include methaemoglobinaemia with cyanosis, hypoglycaemia, hypothyroidism, neurological reactions (including aseptic meningitis, ataxia, benign intracranial hypertension, convulsions, dizziness, drowsiness, fatigue, headache, insomnia, depression, peripheral or optic neuropathies, psychosis, vertigo), jaundice and kernicterus in premature neonates. Pseudomembranous colitis may occur with alterations in bacterial flora of the gastrointestinal tract.
4.9 Overdose
Symptoms:
Nausea, diarrhoea.
Treatment:
Continuous forced fluids may be necessary and the urine should be rendered alkaline. Otherwise treatment is symptomatic.
5. Pharmacological Properties
5.1 Pharmacodynamic Properties
Sulphonamides (including sulfadiazine) are structural analogues and competitive antagonists of p-aminobenzoic acid preventing bacterial utilisation of PABA in the synthesis of folic acid.
5.2 Pharmacokinetic Properties
Sulfadiazine is rapidly absorbed from the gastrointestinal tract after oral dosage. Peak blood concentrations are reached within three to six hours, and about 50% is bound to plasma protein.
The serum half-life is about 17 hours, and about 80% of the dose is excreted in the urine within two to three days.
5.3 Preclinical Safety Data
There are no pre-clinical data of relevance to the prescriber that are additional to those included in other sections.
6. Pharmaceutical Particulars
6.1 List Of Excipients
Maize starch
Pre-gelatinised starch
Microcrystalline cellulose
Sodium starch glycollate
Talc
Magnesium stearate
6.2 Incompatibilities
Sulphonamides are physically incompatible with penicillins, noradrenaline and insulin.
6.3 Shelf Life
36 months.
6.4 Special Precautions For Storage
Do not store above 25°C.
Store in the original container.
Protect from light.
6.5 Nature And Contents Of Container
Polypropylene or polyethylene containers of 500 and 100 tablets.
Polypropylene or polyethylene securipac in cartons of 56 tablets.
7. Marketing Authorisation Holder
Wockhardt UK Ltd
Ash Road North
Wrexham
LL13 9UF
UK
8. Marketing Authorisation Number(S)
PL 29831/0191
9. Date Of First Authorisation/Renewal Of The Authorisation
01/05/2008
10. Date Of Revision Of The Text
01/05/2008
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