Special Groups in Prescribing Flashcards
(22 cards)
What effects the Elderly population’s absorption?
- Decreased gastric acid
- Decrease GI motility
- Decreased Splenic blood flow
- Decreased Liver size
- Decreased Liver Blood flow
What effects the Elderly population’s distribution?
- Less lean body mass
- Decreased total body water
- Increased body fat
- Decreased blood proteins
What effects the Elderly population’s metabolism and excretion?
- Decreased liver size
- Decreased liver blood flow
- Decreased glomerular filtration
- Decreased tubular re-absorption
What is an orthostatic response?
Examples of drugs which can cause this…
Blunting of the normal tachycardia response that occurs on standing or vasodialiation. Decreased with age.
E.g. Benzodiazepines, Opioids
Postural control/stability relies on…
Static reflexes. Ageing reduces frequency + amplitude of corrective movements.
Corrective movements based on D3 receptors, decrease in age.
Cholingeric transmission
Cholinergic transmissionrefers to the process by which nerve cells useacetylcholine as their chemical messenger (neurotransmitter) to communicate with other cells.
In children/neonates why are there more off licence medications?
Ethics surrounding clinical trials in this age groups
Enzymes in infants and neonates
They have limited/no enzymes, particularly CYP450
When does renal maturity occur in children?
6-8 months
What parameters do we base dosing off in children?
Height and weight
Why is pregnancy and breastfeeding significant in prescribing?
Some drugs will cross the placenta barrier or exreted in milk. This can interfere with fetal development/infant.
Causes of AKI
(Acute Kidney Injury)
- Dehydration
- Sepsis
- Medications
- Obstruction
- Acute glomerulonephritis
Causes of CKD
(Chronic Kidney Disease)
- Diabetes
- Hypertension
- Chronic Glorulonephertitis
- Polycystic kidney disease
- Long term obstruction
What 2 ways can we assess kidney function?
- EGFR
- Creatine Clearance
Risk Factors for AKI
Over 75yrs
CKD, low eGFR
Cardiac failure
Liver disease
Diabetes
Nephrotoxic medication
Sepsis
Examples of Nephrotoxic Drugs
- Fluids (too much/little)
- Calcium channel blockers (Amlodipine)
- ACE inhibitors (Ramipril)
- Angiotensin blockers
- NSAIDS
What are high extraction drugs?
Drugs readily cleared by the liver.
E.g. Morphine, propranolol
What is the dosing of high extraction drugs in severe hepatic impairment?
10-50% normal dosing
What are Low extraction drugs?
Drugs that are cleared hepatically, but not the sole exretion route.
E.g. Benzodiapines, Warfarin
What is the dosing of low extraction drugs in hepatic impairment?
Usually 50% of normal dose
Hepatic Failure Dosing
Doses must be titrated to response as clearance is unpredictable
Groups of medicines to avoid in hepatic failure if possible
- Sedating
- Hepatotoxic
- Those associated with haemorrhage
