Monitoring Drug Therapy Flashcards
What is the importance of monitoring? (3)
- Aid diagnosis
- Effectiveness of treatment
- ADRs
What can be monitored from blood tests? (6)
- Urea and electrolytes
- Haematology
- Renal function
- Liver function
- Cardiac enzymes
- TDM - Therapeutic drug monitoring
What can be monitored from clinical observations? (6)
- BP, Pulse
- Oxygen saturation
- Resp rate
- Urine output, fluid balance
- Pain score
- Blood glucose
What is the purpose for checking Urea and electrolyte levels?
1. They provide essential info that indicate: Renal function Hydration status Assess disease state Identify possible ADRs
Why are Creatinine levels measured?
Help to determine the estimated GFR
Whats the normal level of sodium and what do abnormal levels indicate?
Normal levels are between 133-146mmol/L
Regulated by aldosterone (RAAS system)
Abnormal levels usually indicated water loss/imbalance.
LOW levels - HYPOtension
HIGH levels - HYPERtension
What is the function of sodium? (3)
Extracellular cation
Pumped by Na/K ATPase
Maintains normal function of muscles and nerves
What is the RAAS system?
Renin–angiotensin–aldosterone system.
- Regulates fluid balance and blood pressure.
- System activates when low bp or blood volume – homeostatic response to increase bp and CO.
- Aldosterone is a minerolocorticoid (secreted from adrenal cortex) which enhances Na+ reabsorption and promotes K+ excretion
What are the causes (5) and symptoms (6) of Hypernatraemia?
Na >146mmol/L
Causes:
1. Insufficient water intake
2. Excessive water loss
3. Too much Na retention or from diet
4. Pharmacological - Corticosteroids, NSAIDs & Lithium toxicity
5. Excess adrenocorticoid hormones e.g Cushings syndrome
Symptoms:
- Fever
- Tachycardia
- Hypertension
- Dizziness
- Increased thirst
- Oedema
What are the causes (3) of Hyponatraemia?
Na
What are the symptoms (6) of Hyponatraemia?
Symptoms:
- Headache
- Nausea
- Vomiting
- Cramps
- Circulatory failure
- Postural Hypotension
Describe potassium and its role in the body?
- 5-5.3 mmol/L
- Largely intracellular whos needs are met from dietary sources.
- Essential for maintaining muscle contractility
- Maintains fluid balance, nerve impulse function and muscle function
What are the causes of Hyperkalaemia?
K>5.3mmol/L Causes: 1. Renal failure 2. Metabolic acidoisis 3. K+ supplements 4. Drugs: ACE inhibitors, Beta Blockers, Heparin
At what level of K+ reduces the blood pH reduced by 0.1?
K+ increase 0.6 mmol/L
How do beta-blockers cause hyperkalaemia?
They suppress catecholamine-stimulated renin release, thereby decreasing aldosterone synthesis and decrease cellular uptake of potassium
What occurs when K+ levels reach over 6mmol/L?
Cardiac Toxcitity
- Arrhythmia
- Tachycardia
- Ventricular fibrillation
- Asystole - (condition where the heart ceases to beat)
Treatment options of hyperkalaemia? (5)
- Stop offending medication
- Resistrict potassium intake
- IV calcium gluconate 10%
- Infusion of insulin + glucose
- Ion exchange resins e.g Calcium resonium
How do you treat Hypovolaemic hypornatraemia?
- Replacement with IV NaCl 0.9%
2. Fluid restriction, diuretics and sodium restriction
How do you treat Euvolaemic Hyponatraemia?
Treat the immediate cause such as hormone replacement. IF not feasible, water restriction isn’t recommended.
How do you treat someone with symptomatic issues of Hypo/hyperatraemia?
Use hypertonic saline 3% infusion
Describe how Hypokalaemia is caused when K+ is more than 3.5mmol/L?
- Inadequate intake
- Loss from GI secretions
- Redistribution between ECF and ICF
- Mineralocorticoid excess e.g. hyperaldosteronism
- Anaemia- immature RBCs
- Drugs: Diuretics, Salbutamol, Theophylline, corticosteroids
- Low potassium levels increase the resting membrane potential which means a great stimulus is needed to produce an action potential
Describe the symptoms that you feel when K+ falls below 2.5mmol/L (hypokalaemia)?
- Muscular weakness 2. Tetany 3. Respiratory failure 4. Paralysis 5. Cardiac Arrhythmias 6. Sudden death
How do you treat Hypokalemia?
- Pottasium effervescent tablets 2. Intravenous pottasium (usually mixed with glucose or sodium chloride) at 20-40mmol/l 3. BANANAS
Describe calcium and its role in the body? How are the levels of calcium affected too?
- Parathyroid hormone, Vitamin D metabolites (calcifedol and calcitriol), calcitonin are hormones which control it
- Structural element in bones and teeth
- Mediates vasoconstriction/dilation, nerve impulse transmission, muscle contraction and secretion of hormones (insulin)
- Co-factor for enzymes and protein
- Levels are affected by high or low albumin concentration
- 40 to 50% are bound to plasma proteins and only free calcium is active
- Levels of calcium must be adjusted for high or low albumin
- Interpreting calcium results- corrected calcium favoured
Describe what Hypercalcaemia is?
- The decreased serum PTH and increased serum calcitonin 2. It stops the calcium from being absorbed by the GI tract, decreases bone reabsorption, and increases calcium excretion from the kidneys