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Sulfadiazine oral

Updated 2 Feb 2023 | Sulfonamides & trimethoprim


Tablets containing sulfadiazine

Drugs List

  • sulfadiazine 500mg tablets
  • Therapeutic Indications


    Antibiotic sensitive infections
    Prevention of rheumatic fever recurrence

    Prevention of recurrence of rheumatic fever.

    Treatment of infection caused by susceptible organisms, for example:
    Gram positive bacteria such as group A Streptococci and some strains of Streptococcus pneumoniae, Bacillus anthracis, Nocardia (especially N. asteroides), Actinomyces spp., Staphylococci and Clostridium perfringens.

    Gram negative bacteria such as Haemophilus influenzae, H. ducreyi, Escherichia coli, Klebsiella, Proteus, Salmonella, Serratia, Vibrio cholerae, Brucella, Legionella, Yersinia pestis, Chlamydia, Pseudomonas pseudomallei.

    Note that sensitivity to sulfadiazine varies widely in the Enterobacteriaceae.

    Sulfadiazine should not be used for the initial treatment of meningococcal meningitis although may be used instead of parenteral penicillin once susceptibility to sulfadiazine is established.

    Unlicensed Uses

    Congenital toxoplasmosis in combination with other drugs
    Foetal toxoplasmosis in pregnancy in combination with other drugs
    Ocular toxoplasmosis in combination with other drugs
    Toxoplasmosis in the immunocompromised in combination with other drugs

    Foetal toxoplasmosis in pregnancy in combination with pyrimethamine and folinic acid
    Congenital toxoplasmosis in combination with pyrimethamine and folinic acid
    Toxoplasmosis in the immunocompromised in combination with other drugs
    Ocular toxoplasmosis in combination with other drugs



    Treatment of susceptible infections
    Initial dose: 2g to 4g.
    Maintenance dose: Up to 4g daily in divided doses for a maximum of seven days.

    Prevention of recurrence of rheumatic fever
    Patients weighing 30kg and above: 1g daily.
    Patients weighing less than 30kg: 500mg daily.


    Treatment of susceptible infections
    Initial dose: 75mg/kg
    Maintenance dose: 150mg/kg daily in divided doses.
    Maximum dose: 6g daily.

    Toxoplasmosis in pregnancy (in combination with pyrimethamine and folinic acid) (unlicensed)
    Children aged 12 to 18 years: 1g three times daily until delivery.


    Congenital toxoplasmosis (in combination with pyrimethamine and folinic acid) (unlicensed)
    50mg/kg twice daily for twelve months.

    Patients with Renal Impairment

    The manufacturer contraindicates use in patients severe renal impairment and to use sulfadiazine with caution in patients with mild to moderate renal impairment. A reduction in dose may be necessary.

    The Renal Drug Handbook suggests the following doses in renal impairment:
    Glomerular Filtration Rate 20 to 50ml/minute
    Dose as in normal renal function.

    Glomerular Filtration Rate 10 to 20ml/minute
    Use 50% of dose and monitor levels.

    Glomerular Filtration Rate less than 10ml/minute
    Use 25% of dose and monitor levels.


    Haematological disorder
    Severe hepatic impairment
    Severe renal impairment

    Precautions and Warnings

    Allergic disposition
    Predisposition to folate deficiency
    G6PD deficiency
    Immunodeficiency syndromes
    Mild hepatic impairment
    Mild renal impairment
    Systemic lupus erythematosus

    Consult national/regional policy on the use of anti-infectives
    Folate supplementation may be necessary in some patients
    Ensure patient has adequate fluid intake
    Maintain hydration and urinary output
    Monitor for signs of bone marrow depression
    Monitor plasma levels and adapt dose in patients with renal impairment
    Perform blood counts on prolonged use of this treatment
    Discontinue immediately if blood disorders or rashes develop
    Advise patients to report skin rash

    Use with caution in patients with severe allergy or bronchial asthma. Sulfonamides may cause allergic-type reactions including anaphylactic symptoms and life-threatening or less severe asthmatic episodes in susceptible individuals.

    Advise patients to report incidence of rash. Discontinue treatment at first appearance of skin rash. Severe reactions and fatalities have been reported in sulfonamide use including Stevens-Johnson syndrome, Lyell syndrome (toxic epidermal necrolysis), fulminant hepatic necrosis, agranulocytosis, aplastic anaemia, other blood dyscrasias and hypersensitivity of the respiratory tract. If patients develop Stevens-Johnson syndrome or toxic epidermal necrolysis, sulfadiazine treatment must not be re-started.

    Advise patients to consume 5 to 6 pints of fluid every 24 hours. It is essential to maintain an adequate fluid intake and urinary output. If necessary, the urine may be rendered alkaline to prevent crystallisation of acetyl sulfadiazine. The low solubility of sulfadiazine and its acetyl derivative means that crystalluria is more likely with sulfadiazine than sulfamethoxazole.

    Haemolysis may occur in patients with glucose-6-phosphate dehydrogenase deficiency.

    Monitor blood counts monthly in patients on long-term treatment as asymptomatic changes may occur due to the lack of available folate. Blood counts should also be taken in patients who are predisposed to folate deficiency (such as the elderly, chronic alcoholics and patients with rheumatoid arthritis), patients with malabsorption syndromes or malnutrition, and patients receiving concurrent anticonvulsant medication.

    Pregnancy and Lactation


    Use sulfadiazine with caution in pregnancy.

    Briggs suggests because of the potential toxicity to the newborn, sulfonamides should be avoided near term. The manufacturer suggests the risks and benefits of therapy should be considered before sulfadiazine is used in pregnancy. It is generally recommended that sulfadiazine is not administered late in pregnancy due to the risk of haemolytic anaemia in the newborn.

    There is epidemiological evidence of the safety of sulfadiazine during therapy, however animal studies with high doses have shown evidence embryotoxicity and teratogenicity, especially during the first trimester.

    For treatment of toxoplasmosis in pregnancy, seek specialist advice; the regimen should include folinic acid.

    The use of all medication in pregnancy should be avoided whenever possible; particularly in the first trimester. Non-drug treatments should also be considered. When essential, a medication with the best safety record over time should be chosen, employing the lowest effective dose for the shortest possible time. Polypharmacy should be avoided. Teratogens taken in the pre-embryonic period, often quoted as lasting until 14 to 17 days post-conception, are believed to have an all-or-nothing effect. Where drugs have a short half-life, and when the date of conception is certain, this may allow women to be reassured where drug exposure has occurred within this time frame. Further advice may be available from the UK National Teratology Information Service (NTIS) and through ToxBase, available via password on the internet ( ) or if this is unavailable at the backup site ( ).


    Use sulfadiazine with caution in breastfeeding.

    Briggs suggests sulfonamide excretion into breast milk does not pose a significant risk to a healthy, full-term neonate. However exposure to sulfonamides via breast milk should be avoided in ill, stressed or premature infants and in infants with hyperbilirubinemia or glucose-6-phosphate dehydrogenase (G6PD) deficiency. The manufacturer suggests a decision to continue/discontinue breastfeeding or to continue/discontinue therapy with sulfadiazine should be made following assessment of the risks and benefits of therapy.

    Sulfonamides are excreted in breast milk in small amounts. There is a risk of kernicterus in the neonate and a risk of haemolysis in breastfed G6PD deficient neonates.

    Neonates, infants born prematurely, those with low birth weight, those with an unstable gastrointestinal function or who have serious illnesses may require special consideration. For any infant, if a drug is prescribed to the nursing mother, it should be at the lowest practical dose and for the shortest time. When drug administration is unavoidable and breastfeeding is to continue, minimisation of exposure of the infant to the drug may sometimes be achieved by timing the maternal doses to just after a feeding episode. Infants exposed to drugs via breast milk should be monitored for unusual signs or symptoms. Interactions between the drug received by the infant from the mother's milk and medication prescribed for the infant should also be considered, for example, when the drug given to the infant may prevent metabolism of the drug received via breast milk.
    Specialist advice is available from the UK Drugs in Lactation Advisory Service at


    Advise the patient to consume 5 to 6 pints of water every 24 hours to maintain a high urine output.

    Advise patients to report incidence of rash.

    Side Effects

    Antibiotic-associated colitis
    Aplastic anaemia
    Aseptic meningitis
    Back pain
    Benign intracranial hypertension
    Blood disorders
    Contact dermatitis
    Erythema nodosum
    Exfoliative dermatitis
    Fibrosing alveolitis
    Haemolytic anaemia
    Hepatic necrosis
    Hypersensitivity reactions
    Interstitial nephritis
    Neurological effects
    Optic neuropathy
    Peripheral neuropathy
    Pseudomembranous colitis
    Pulmonary eosinophilia
    Renal failure
    Renal tubular necrosis
    Serum sickness-like reactions
    Stevens-Johnson syndrome
    Systemic lupus erythematosus
    Toxic epidermal necrolysis


    It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.

    The following number will direct the caller to the relevant local centre (0844) 892 0111

    Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( ) or if this is unavailable at the backup site ( ).

    Further Information

    Last Full Review Date: July 2014

    Reference Sources

    Martindale: The Complete Drug Reference, 37th edition (2011) ed. Sweetman, S. Pharmaceutical Press, London.

    Summary of Product Characteristics: Sulfadiazine 500 mg tablets. Wockhardt UK Ltd. Revised May 2014.

    The Renal Drug Handbook. 3rd edition. (2009) ed. Ashley, C and Currie, Radcliffe Publishing Ltd, Abingdon.

    NICE Evidence Services Available at: Last accessed: 04 September 2017

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