1
Q
Who are these specific groups of patients you need to be wary of when prescribing ?
A
- Patients with hepatic or renal impairment
- Elderly
- Pregnant women
- Breastfeeding women
- Neonates, infants, young people, “children”
- Terminally ill/end of life
- Ethnic minorities or if English is not their first language
- Incapacitated patients
- Culturally diverse groups e.g. Travellers, immigrants, refugees
- Patients unable to consent to treatment
- A typical patient group in your own specialist area e.g. respiratory patients or patients with mental health problems
- Those with co-morbidities
- Others?
2
Q
Explain Prescribing in Hepatic Impairment
A
- The liver is the main drug to metabolise drugs.
- Hypalbuminaemia (hypoproteinaemia) in severe liver disease limits availability for drug binding, thus increasing unbound concentration
Toxicity may occur in highly protein bound drugs with a narrow therapeutic index eg phenytoin or prednisolone. - Hepatic encephalopathy, ascites and deficiencies in clotting factors can increase sensitivity to some drugs
- Drugs that cause sedation, constipation or hypokalaemia are contraindicated in severe liver disease as these can cause encephalopathy e.g. opiates & benzodiazepines
- Ascites may be worsened by any drug that causes fluid retention e.g. NSAIDs
- Anticoagulants will require careful monitoring if used at all & care with aspirin, NSAID
- Hepatotoxcitity – Many drugs can cause liver damage and theoretically should be avoided in patients with liver disease
- In practice most can be used safely with dose adjustment e.g. paracetamol EXCEPT:
- Methotrexate in alcoholic liver disease
3
Q
Prescribing in renal impairment
A
- The kidney is a major organ involved in excretion of drugs
- Any decrease in GFR can potentially affect drug clearance
- Reduced excretion of a drug (or its metabolites) can cause toxicity
- Sensitivity to some drugs is increased even if elimination is unimpaired;
- Many side effects are poorly tolerated by patients with renal impairment (Pharmacodynamic effects)
- Some drugs are ineffective when renal function is reduced
- Nephrotoxic drugs should be avoided if possible in patients with renal disease
- Many of these problems can be avoided by reducing the dose or by using alternative drugs.
- If even mild renal impairment is considered likely on clinical grounds, renal function should be checked before prescribing any drug which requires dose modification.
4
Q
What are nephrotoxic drugs
A
Nephrotoxins
* Antibiotics (gentamycin)
* NSAIDs and COX-2 inhibitors (naproxen)
* ACE inhibitors and ARBs (ramipril)
* Diuretics (Bendroflumethiazide)
* Renally cleared drugs (insulin)
5
Q
A
