Past Papers · SAQ
Diuretics — Frusemide Biochemistry
2012A Q16
Exam questionDescribe the biochemical abnormalities, and the mechanisms by which they arise, that may be observed in a patient who is taking frusemide.
CICMWrecks answer
Master answer
Frusemide:
- Loop Diuretic
- MOA:
- Inhibition of Na/K/2Cl symporter TAL of LoH.
- ↓ reabsorption of Na, K, Cl.
- Less positive luminal charge
Biochemical Abnormalities with Frusemide
| Abnormality | Mechanism |
|---|---|
| Hyponatraemia | Blockade of Na/K/2Cl symporter – ↓ trans cellular Na reabsorption – loss of luminal positive charge → ↓ paracellular Na reabsorption |
| Hypokalaemia | Blockade of Na/K/2Cl symporter – loss of paracellular reabsorption of K |
| Hypochloraemia | Blockade of Na/K/2Cl symporter |
| Hypomagnesaemia/hypocalcaemia | loss of luminal positive charge → ↓ paracellular reabsorption of Mg and Ca |
| Hyperuricaemia | ↓ECF → ↑renin → ↑aldosterone → ↓ Urea secretion and ↑ tubular reabsorption of urea |
| Hyperglycaemia | ↓ glycolysis in RBCs ↓ sensitivity of insulin-induced skeletal muscle uptake |
| Metabolic Alkalosis | ↓ plasma chloride → ↑SID → alkalosis |
Gladwin 2016
Past papers
Exam appearances
| Exam | Exact exam wording | Candidate success |
|---|---|---|
| 2012A Q16 | Describe the biochemical abnormalities, and the mechanisms by which they arise, that may be observed in a patient who is taking frusemide. | 30% |