Factor | Comment |
---|---|
Diagnosis | Primary – condition to be treated |
Secondary – other conditions that may influence the benefit-to-harm balance | |
Prognosis | Influences the likely duration of benefits and harms of treatment |
Drug factors | |
Pharmacokinetic | Frequency of dosing – influences adherence
Bioavailability – if consistent, makes drug response more predictable Tissue distribution – influences the likelihood of adverse effects at sites other than those targeted Routes of metabolism/excretion – influences the variability of response in the presence of renal or hepatic disease Drug interactions – influences response for patients who are (or may be) subjected to polypharmacy |
Pharmacodynamic | Target specificity and selectivity – influences the likelihood of adverse effects
Dose-response characteristics – influences ease of dose titration Therapeutic index – influences ease of dose selection |
Efficacy | Beneficial impact on important outcomes such as cure, symptom relief, disease progression, morbidity, hospitalisation and mortality |
Safety | Frequency of adverse effects
Seriousness of adverse effects (eg allergy, idiosyncratic reactions) Ease with which adverse effects can be predicted, monitored and prevented |
Cost-effectiveness | Availability of alternatives with similar efficacy and safety but lower cost |
Patient factors | Health beliefs and attitude to risk
History of previous adverse drug reactions Vulnerability to adverse effects (eg organ damage, reduced physiological reserve) Current drug therapy, including interacting drugs Likely adherence to therapy or follow-up monitoring |
Prescriber factors | Familiarity with prescribing choices
Ease of follow up may depend on resources |