Co-trimoxazole

Trimethoprim & Combinations · Sulphonamide

Indications

Infections of respiratory, gastro-intestinal, urinary tracts and skin.

Dosage

ORAL: Adults: 2 tab of 80/400 mg or 1 tab of 160/800 mg or 20 mL of 40/200 mg or 10 mL of 80/400 mg susp twice daily. Children: Susp 40/200 mg: Under 6 wk, not recommended; 6 wk-5 mth, 1.25 mL susp; 6 mth-5 yr, 2.5 mL susp; 6-12 yr, 5 mL susp. All twice daily. INJECTION: Severe infection: Adults: By IV, 960 mg every 12 hr increase to 1.44 gm every 12 hr. Children: 36 mg/kg daily in two divided doses increase to 54 mg/kg daily.

Administration

IV: Infuse over 60-90 min, must dilute well before giving. May be given less diluted in a central line. Not for IM injection. Maintain adequate fluid intake to prevent crystalluria. Administer around-the-clock every 6-12 hours. Compatibility: Stable in D5 ½NS, LR, 0.45% NS. At Y-site administration, incompatible with fluconazole, midazolam, vinorelbine. When admixed, incompatible with fluconazole, verapamil. Stability: Do not refrigerate injection. Less soluble in more alkaline pH. Protect from light.

Adverse Effects

Nausea, vomiting, glossitis, skin rashes. Blood dyscrasias. Folate deficiency. Liver changes. Rarely erythema multiforme, Lyell syndrome, exfoliative dermatitis. Stevens-Johnson syndrome, convulsions, peripheral neuritis, ataxia, candidal infection, hyperkalaemia, headache, GI upset, rash, cholestatic jaundice, epidermal necrolysis, Steven-Johnson syndrome, drug reaction with eosinophilia and systemic symptoms, respiratory reactions.

Risk Factor (Pregnancy/Lactation)

Pregnancy: Contraindicated in pregnancy. Lactation: Contraindicated or not recommended. Contraindications: Neonates. Severe renal or hepatic insufficiency. Blood dyscrasias. Acute porphyria. Precautions: Elderly. Renal impairment (reduce or space out dosage). Severe allergy or asthma. Folate or G6PD deficiency. Perform regular haematological tests during long term therapy. Discontinue if rash develops. Maintain adequate urinary output. Risk of metabolic acidosis. Monitor serum potassium and sodium in those at risk of hyperkalemia or hyponatraemia.

Interactions

Folate inhibitors, anticoagulants, anticonvulsants, hypoglycaemics, cyclosporin, procainamide, amantadine, lamivudine, thiazides, pyrimethamine, digoxin, ACE inhibitors, angiotensin II antagonist, K sparing diuretics, phenytoin, zidovudine, other drugs that cause hyperkalaemia, dapsone, azathioprine, folinic acid.

Advice to Patient

Take with meals. Swallow with a full glass of water. Contact prescriber if there is rash, chest pain, palpitations, abnormal anxiety, hallucinations, seizures, unusual cough, sore throat, dark stool, shortness of breath, unusual bruising or bleeding. Avoid direct sunlight. Use sunscreen, wear protective clothing and sunglasses to prevent photosensitivity.

Pharmacokinetics

Absorption: Oral: Rapid; almost completely absorbed (90%-100%). Metabolism: Hepatic. Half-life elimination: TMP: Prolonged in renal failure. Newborns: Approx. 19 hrs. Infants 2 mth-1 yr: Approx. 4.6 hrs. Children 1-10 yrs: 3.7-5.5 hrs. Children and Adolescents >10 yrs: 8.19 hrs. Adults: 6-11 hrs. SMX: 9-12 hrs, prolonged in renal failure. Time to peak, serum: Oral: 1-4 hrs. Excretion: Urine.

Brands with this active ingredient

Compiled by Healify Pharmacy from published drug references. How we compile it →

Always consult a pharmacist or doctor.