PAST QUESTIONS – H02. Renal Pharmacology (Click to Open)
SYLLABUS (Fourth Edition, 2023)
| LEVEL 1 | LEVEL 2 | LEVEL 3 |
|---|---|---|
| Diuretics | ||
| Loop of Henle – Frusemide / Furosemide | Distal tubule or collecting duct – Thiazides and Aldosterone antagonists | |
| Proximal tubule – Carbonic anhydrase inhibitors | ||
| Osmotic agents – Mannitol | ||
| Renal Replacement Fluid | ||
N.B. The Syllabus tables used in out Pharmacopeia seem incomplete, but that is intentional because we have only included groups/classes/drugs which are mentioned directly in the syllabus or have been asked before in the exams.
TRAINEE EXPECTATIONS
- Trainees are expected to understand a drug’s pharmacology in the context of normal physiology, extremes of age (i.e., neonates, paediatrics, and the elderly), obesity, pregnancy (including foetal implications) and critical illness. An understanding of potential toxicity and relevant antidotes is also expected. Agents may be listed in more than one section when they are used for different indications.
- This is not an exhaustive list of all drugs relevant to or important in ICU practice. Each drug or classes of drugs have been assigned a details of understanding level outlined below. This is a guide to the minimum level of knowledge expected for that drug.
- For classes of drugs where examples are not specified, it is suggested a prototypical drug from the class be studied, as well as the relevant variations within the class exploring the major differences that exist between the agents in that class.
LEVELS OF UNDERSTANDING
| Level 1 | Level 2 | Level 3 |
|---|---|---|
| For these drugs, a detailed knowledge and comprehension of: | For these drugs a detailed knowledge of: | For these drugs a detailed knowledge of: |
| Class, Indications, and dose | ||
| Mechanism of Action | ||
| Pharmacodynamics and Adverse effects | ||
| Pharmacokinetics | Important pharmacokinetic differences or considerations when using in ICU | |
| Pharmaceutics | ||
CICMWrecks Tables (Click to Open)
| MASTER TABLES | Diuretics |
| Renal Replacement Fluids | |
| INDIVIDUAL TABLES |
RENAL REPLACEMENT FLUIDS (Level 3)
- Typically pre-packaged in 5L bags of sterile water
- contain sterile water, electrolytes and buffer
- Vary slightly in composition, but all are balanced salt solutions with either a lactate, bicarbonate or citrate buffer
- Bicarbonate-based solutions: most commonly used two-compartment systems. 25-35mmol/L and used as both dialysate and replacement fluids
- Lactate-based solutions: stable, cheaper, practical. But buffering capacity depends on conversion of lactate to bicarbonate. So not commonly used in CRRT
- Citrate-based solutions: new generation, administered prefilter. Advantage that additional anticoagulation is not required.
- Calcium-free solutions: When citrate-based fluids are used prefilter, these are used as dialysate and replacement fluids
- At present, there is no evidence to suggest that the choice of replacement fluid has an impact on survival or renal recovery.
- Replacement fluid can be added pre- or postfilter in varying ratios.
- The benefit of adding some of the replacement fluid prefilter is that it lowers the hematocrit of the blood, which reduces the likelihood of the filter clotting.
- The downside is that predilution reduces solute clearance and a compensatory increase in flow rates should be considered (15% for ultrafiltration rates of 2 L/h and up to 40% for rates of 4.5 L/h).
| Composition (mmol/L) | PrismOcitrate 18/0 (Baxter) | PrismOcal (Baxter) | PrismOcal B22 (Baxter) | Prismasol (Baxter) | Hemosol B0 (Baxter) |
|---|---|---|---|---|---|
| Sodium | 140 | 140 | 140 | 140 | 140 |
| Potassium | 0 | 0 | 4 | 0 | 0 |
| Calcium | 0 | 0 | 0 | 1.75 | 1.75 |
| Magnesium | 0 | 0.5 | 0.75 | 1 | 0.5 |
| Chloride | 86 | 106 | 120 | 110 | 109.5 |
| Bicarbonate | 0 | 32 | 22 | 32 | 32 |
| Phosphate | 0 | 0 | 0 | 0 | 0 |
| Citrate | 18 (=54mmol bicarb post metabolism) | – | – | – | – |
| Lactate | 0 | 3 | 3 | – | 3 |
| Osmolality (mOsmol/L) | 244 (280 post metabolism) | 282 | 282 | 287 | 287 |
Source: Mishra, Rajesh Chandra. ISCCM Manual Of RRT And ECMO In ICU A Reference Book For Practicing Intensivists (p. 25). Jaypee Brothers Medical Publishers.
Kerr’s notes
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