List of side effects of trimethoprim/sulfamethoxazole explained

The following list contains adverse effects by incidence of trimethoprim/sulfamethoxazole.^{[1] [2] [3] [4] [5] [6] [7]}

Common (>1% frequency)

• Fever
• Nausea
• Vomiting
• Diarrhea
• Weight loss
• Rash
• Muscle aches
• Joint pain
• Itch
• Sore mouth
• Hyperkalaemia (high blood potassium)
• Thrombocytopenia (low number of platelets in the blood)

Infrequently (0.1–1.0% frequency)

• Headache
• Jaundice
• Elevated liver transaminases
• Peripheral neuritis
• Drowsiness
• Constipation
• Photosensitivity (light sensitivity)
• Blood dyscrasias (e.g. neutropaenia)

Rare (<0.1% frequency)

• Megaloblastic anaemia
• Methaemoglobinaemia
• Erythema multiforme
• Low blood sugar
• Hepatitis (liver swelling)
• Crystalluria (crystals in the urine)
• Urinary obstruction causing difficulty passing urine
• Lowered mental acuity
• Depression
• Tremor
• Aplastic anaemia
• Haemolytic anaemia
• Hyponatraemia
• Purpura
• Eosinophilia
• Agranulocytosis
• Serum sickness
• Anaphylaxis
• Allergic myocarditis
• Angioedema
• Drug fever
• Periarteritis nodosa
• Hepatic necrosis
• Pancreatitis
• Myelosuppression
• Haemolysis^[8]
• Stevens–Johnson syndrome^[9]
• Drug reaction with eosinophilia and systemic symptoms
• Toxic epidermal necrolysis^[10]
• Ataxia^[11]
• Clostridium difficile colitis
• Aseptic meningitis^[12]
• Pseudomembranous colitis
• Interstitial nephritis
• Fulminant hepatic necrosis
• Hypersensitivity of the respiratory tract
• Sore throat
  • Pallor Arthralgia

Unknown frequency

• Hallucinations
• Cough
• Glossitis
• Stomatitis
• Fatigue
• Insomnia
• Impaired kidney function
• Pulmonary infiltration^[13]
• Shortness of breath

Notes and References

1. Web site: Bactrim, Bactrim DS (trimethoprim/sulfamethoxazole) dosing, indications, interactions, adverse effects, and more. Medscape Reference. WebMD. 13 January 2014.
2. Web site: BACTRIM. TGA eBusiness Services. Roche Products Pty Limited. 18 September 2012. 13 January 2014. PDF.
3. Web site: BACTRIM DS (sulfamethoxazole and trimethoprim) tablet BACTRIM (sulfamethoxazole and trimethoprim) tablet [AR Scientific, Inc.]]. DailyMed. AR Scientific, Inc.. June 2013. 13 January 2014.
4. Web site: Co-Trimoxazole Tablets 80/400mg - Summary of Product Characteristics (SPC). electronic Medicines Compendium. Actavis UK Ltd. 17 October 2012. 13 January 2014.
5. Book: 978-0-85711-084-8 . British National Formulary (BNF) . Joint Formulary Committee . 2013 . Pharmaceutical Press . London, UK . 65 . registration .
6. Book: Rossi, S . 978-0-9805790-9-3 . Australian Medicines Handbook . Adelaide . The Australian Medicines Handbook Unit Trust . 2013 . 2013 .
7. Web site: e-Therapeutics+e-CPS. Sulfamethoxazole-Trimethoprim CPhA Monograph. 28 March 2015.
8. Breakdown of red blood cells. This side effect most often occurs in people with glucose-6-phosphate dehydrogenase deficiency
9. A potentially fatal skin reaction that causes the skin to slough off
10. Basically a worse form of Stevens–Johnson syndrome
11. Incoordination; most often after IV use in HIV patients
12. Swelling of the membranes surrounding the brain and spinal cord without any obvious infectious cause
13. Sign of hypersensitivity