Who can administer
May be administered by registered competent doctor or nurse/midwife
Important information
- Confusion and medication errors have occurred because of the different expression of dose in the European and the USA markets: take GREAT care if using USA references (in USA- doses are generally expressed based on trimethoprim component only- rather than on the combination of trimethoprim/sulfamethoxazole)
- Ensure high doses used for PJP (PCP) infection -see below
- High doses require large volume infusions - read "Methods of intravenous administration" carefully
- Monitoring requirements -see overleaf
- See under 'Dose' for adjustments required in renal impairment
- Can cause rare but serious skin adverse effects, e.g. Stevens-Johnson syndrome, and other adverse effects such as blood dyscrasias, especially in elderly patients
- This medicine may cause venous irritation and tissue damage in cases of extravasation.
- For Y-site compatibility see below
Available preparations
Septrin 480mg per 5ml ampoule
Reconstitution
Already in solution
Draw up using a 5 micron filter needle
Dilute further prior to administration
Infusion fluids
Glucose 5% must be used for all fluid restricted patients under (a) below
Sodium chloride 0.9% can be used if using dilution specified under (b) below
Methods of intravenous administration
Intermittent intravenous infusion (using an electronically- controlled infusion device)
a: Fluid restricted e.g. PJP treatment (ref 1)
- To avoid crystalisation each 1ml of injection solution (480mg/5ml) MUST be diluted to a minimum of 15ml Glucose 5% ONLY
- Administer required dose over 60 minutes (reduced stability so shorter infusion time needed)
- Examples given in table below
- Check for haze or precipitation during preparation or administration- discard if present
| Dose |
Minimum volume of Glucose 5% to use |
| 480mg |
75ml |
| 960mg |
150ml |
| 1200mg |
187.5ml |
| 1440mg |
225ml |
| 1680mg |
262.5ml |
| 1920mg |
300ml |
| 2160mg |
337.5ml |
| 2400mg |
375ml |
| 2640mg |
412.5ml |
| 2880mg |
450ml |
| 3120mg |
487.5ml |
| 3360mg |
525ml |
| 3600mg |
562.5ml |
Round diluent volume up to nearest volume for other doses. e.g. for a dose of 2500mg- administer in a minimum volume of 412.5ml
b: If not fluid restricted - (non PJP treatment)
- Each ml of injection solution to be added to 25ml infusion solution
- Add 5ml solution (480mg) to 125ml infusion solution
- Add 10ml solution (960mg) to 250ml infusion solution
- Add 15ml solution (1440mg) to 375ml infusion solution (round to 500ml for convenience)
- Administer required dose over 60 to 90 minutes
c: Central line (ref 1)
- Anecdotal evidence suggests that as a last resort, cotrimoxazole may be administered undiluted as an infusion via a central line, over 90 to 120 minutes (unlicensed, ref 1)
Should haze or precipitation appear in the solution at any time before or during an infusion, the mixture should be discarded.
Dose in adults
IMPORTANT: Doses below refer to the combination of sulfamethoxazole and trimethoprim- take care if using references that are basing doses on trimethoprim component alone (typically USA references)
PJP (PCP) treatment
- Discussion with Micro/ID is recommended
- Give 120mg/kg/day divided into a 6 to 8 hourly dosing regimen for 14 days (non HIV), or 21 days (HIV) (ref 2)
- e.g. 30mg/kg every 6 hours
- For a 70kg patient: 70x120 = 8,400mg daily, dosing regimen would be 2,100mg every 6 hours (round dose to nearest 480mg=1920mg)
- In severe disease consider oral switch at same dose when clinically improving.
- In mild to moderate disease consider oral route from outset.
Stenotrophomonas maltophilia
Other non-PJP (PCP) infections
- Give 960mg to 1440mg every twelve hours depending on severity of infection
Patients who are nil by mouth (ref 2)
- The same dose can be given by the IV route as the oral route e.g. for PJP prophylaxis 960mg bd three times a week can be given IV
Renal impairment (treatment doses only)(ref 2)
- Monitor levels as advised by Micro/ID
| eGFR (ml/min/1.73m2) |
Dose to use (applies to TREATMENT doses only) |
| Above 30 |
As in normal renal function |
| 15 to 30 |
For PJP: give usual dose for three days, then reduce to 30mg/kg twice daily
For other indications: give 50% of dose from day 1
|
| Less than 15 |
Only use if haemodialysis facilities available
For PJP: give 50% of dose from day one i.e. 30mg/kg twice daily
For other indications: Avoid if possible if levels cannot be monitored (or use 50% of dose if Micro/ID approved)
|
| Renal replacement therapy |
Consult pharmacy or specialist literature sources |
Hepatic impairment
- The BNF advises to avoid in severe hepatic impairment
Monitoring
- Monitor FBC when given long term, or in folate deficient patients, or in elderly patients
- Serum potassium and sodium in patients at risk of hyperkalaemia and hyponatraemia
Further information
- 480mg = 400mg sulfamethoxazole and 80mg of trimethoprim (doses refer to the combination)
- Ensure adequate hydration to prevent crystalluria
- Glucose 5% is the only suitable infusion fluid for fluid restricted regimens - for stability reasons
- Search synonym for intranet (Cotrimoxazole)
Storage
Store below 250C
References
SPC September 2021
1: Medusa Injectable medicines guide, downloaded 20/09/2021
2: GUH Antimicrobial Guidelines 2021
3: Sanford guide to Antimicrobial therapy, accessed online 05/10/21
Therapeutic classification
Antibiotic
