TMP-SMX + spironolactone/ACEi/ARB — hyperkalemia
- Trimethoprim acts like an ENaC blocker
- reduces distal K+ excretion
- ACEi/ARB/MRA also raise potassium
- Hyperkalemia can be abrupt + severe
- Older age/CKD greatly magnify risk
- Check K/Cr; use another antibiotic if able
Interaction at a glance
- Trimethoprim acts like an ENaC blocker
- reduces distal K+ excretion
- Hyperkalemia can be abrupt + severe
Mechanism
- ACEi/ARB/MRA also raise potassium
Clinical consequence
- Hyperkalemia can be abrupt + severe
- Older age/CKD greatly magnify risk
Monitoring
- Trimethoprim acts like an ENaC blocker
- reduces distal K+ excretion
- Check K/Cr; use another antibiotic if able
Self-check
- What should be monitored with TMP-SMX + spironolactone/ACEi/ARB?
K/Cr; use another antibiotic if able.
- What is the main clinical risk of TMP-SMX + spironolactone/ACEi/ARB?
Hyperkalemia can be abrupt + severe.
- What is the key clinical risk of TMP-SMX + spironolactone/ACEi/ARB?
Hyperkalemia.
Drugs in this interaction (30)
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