rational drug prescribing-article

Question 1

RP should

Answer 1

maximise clinical effectiveness minimise harms
avoid wasting scarce healthcare resources
respect patient choice.

Question 2

steps

Question 3

RP steps -diagnosis

Answer 3

Prescribing decisions should be based on the primary diagnosis and relevant sec- ondary diagnoses.

Question 4

RP steps -prognosis

Answer 4

A secondary diagnosis with a poor prognosis, such as lung cancer, will severely limit the benefits of treating a primary one, such as hyper- cholesterolaemia. On the other hand, the excellent prognosis of influenza in a healthy adult limits the potential benefits of antiviral therapy.

Question 5

RP-treatment goals

Answer 5

curing a disease (eg cancer, infection) * relieving symptoms without affecting the underlying condition
(eg headache, diarrhoea)
* combining two outcomes (eg inflam-
matory bowel disease and arthritis) * long-term prevention (eg hyperten-
sion, osteoporosis)
replacing deficiencies (eg hypothy- roidism), and occasionally
*
therapeutic trials to aid diagnosis

Question 6

treatment selection

Answer 6

multiple options

Question 7

monitoring

Answer 7

subjective and objective

Question 8

Drug factors influencing drug selection
Pharmacokinetics

Answer 8

Drugs in the same class (or different formulations of the same drug) may have different bioavailability, dose- concentration curves and half-lives. These factors will determine the dosing schedule.
differ with respect to their specificity for the target organ
reach tissues (eg the brain) to cause adverse effects
are metabolised in the liver or excreted – important in patients with hepatic or renal impairment
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© Royal College of Physicians, 2009. All rights reserved.
Table 2. Factors that influence rational drug and dosage selection.
* are more likely to cause drug interactions by cytochrome P450 inhibition (eg simvastatin versus pravastatin).