TREATMENT SELECTION AND PRESCRIBING

Rational Drug Selection

Define the Patient’s Problem

Problem definition precedes medication selection and includes diagnostic certainty, severity, prior treatment, medication history, organ function, and patient-specific risk (de Vries et al., 1994; Woo & Robinson, 2019c).

• Establish the working diagnosis and the degree of diagnostic certainty. A medication may obscure symptoms, delay the correct diagnosis, or create avoidable harm when the problem has not been adequately defined.
• Determine severity, urgency, expected course, and whether immediate treatment is needed before diagnostic evaluation is complete.
• Review previous treatment, allergies and reaction details, adverse drug reactions, current prescriptions, over-the-counter products, supplements, substance use, adherence, and access barriers.
• Identify pregnancy or lactation, age-related considerations, kidney and liver function, comorbidities, vital signs, relevant laboratory results, and potential interactions.

Specify the Therapeutic Objective

• State what treatment should accomplish. The objective may be cure, symptom relief, replacement of a deficiency, or long-term prevention (de Vries et al., 1994; Woo & Robinson, 2019c).
• Use a measurable target when possible. Define the expected magnitude and timing of response.
• Distinguish a surrogate outcome, such as a laboratory value, from the patient outcome the surrogate is intended to improve.
• Include the patient’s goals and acceptable tradeoffs. A technically effective regimen can fail when its burden, adverse effects, or cost conflicts with what the patient can sustain (NICE, 2015).

Compare Treatment Options

• Begin with current evidence-based guidelines and high-quality evidence that apply to the patient’s condition and population (NICE, 2015).
• Compare efficacy, absolute benefit, time to benefit, adverse effects, contraindications, interactions, therapeutic index, and monitoring requirements (de Vries et al., 1994).
• Evaluate pharmacokinetics and pharmacodynamics in relation to route, onset, duration, organ function, age, pregnancy, genetic factors, and concurrent therapy.
• Consider nonpharmacologic treatment and watchful waiting when either may meet the objective with less risk.
• Use number needed to treat and number needed to harm when valid estimates are available and the study population and follow-up period resemble the clinical situation.

Individualize the Choice

Selecting among therapeutically appropriate options requires systematic evaluation across eight interdependent factors: indication, contraindications and precautions, efficacy, adverse effects, dosing parameters, interactions, adherence and feasibility, and cost and coverage. Omitting any one factor increases the risk of an avoidable adverse outcome or a regimen the patient cannot sustain (de Vries et al., 1994; Woo & Robinson, 2019c).

One mnemonic, I Can PresCribE A Drug, organizes seven factors: Indication, Contraindications, Precautions, Cost/Compliance, Efficacy, Adverse effects, and Dose/Duration/Direction (Woo & Robinson, 2019c).

Another mnemonic, Indications and Contraindications Ensure A Drug Is Appropriately Chosen, applies to this fuller list: Indications, Contraindications, Efficacy, Adverse effects, Dose/route/interval/duration, Interactions, Adherence, Cost.

• Indication: The medication directly addresses the diagnosed or strongly suspected problem.
• Contraindications and precautions: Patient characteristics do not make the expected harm unacceptable.
• Efficacy: Evidence supports a clinically meaningful benefit for the intended outcome.
• Adverse effects: The expected adverse-effect profile is acceptable and manageable.
• Dose, route, interval, and duration: The regimen accounts for pharmacokinetics, organ function, formulation, disease severity, and treatment goal.
• Interactions: The medication list has been reviewed for pharmacokinetic and pharmacodynamic interactions, duplication, and cumulative burden.
• Adherence and feasibility: The patient can obtain, administer, store, and monitor the treatment.
• Cost and coverage: The expected out-of-pocket cost and formulary requirements do not make the regimen inaccessible.

Provider and System Influences

• A personal formulary can improve familiarity with commonly used medications, but it should remain limited, evidence based, and regularly updated rather than becoming a substitute for comparison (Woo & Robinson, 2019c).
• Complex patients may require a systematic review beyond the usual personal formulary, including current guidelines, interaction resources, organ-function adjustments, and consultation when needed (Woo & Robinson, 2019c).
• Payer formularies, prior authorization, and pharmacy availability can affect access. Coverage should be considered without allowing cost alone to displace clinically necessary treatment.
• Pharmaceutical promotion is a source of product information but is not an independent evidence review. Claims should be checked against primary evidence, guidelines, and unbiased drug information (Woo & Robinson, 2019c).
• Guideline updates may change first-line therapy, monitoring, or treatment thresholds. Confirm that the recommendation is current and applicable to the patient’s population and setting.

Start Treatment Safely

Starting therapy includes clear prescription writing, medication reconciliation, avoidance of unnecessary duplication, and dose selection matched to patient risk (de Vries et al., 1994; Woo & Robinson, 2019c).

• Write a complete, unambiguous prescription using the generic name when appropriate. Include strength, dosage form, route, dose, frequency, duration or quantity, refills, and indication when it improves safety.
• Reconcile what the patient should start, continue, change, hold, or stop.
• Avoid unnecessary therapeutic duplication and confirm whether a previous medication requires tapering or washout.
• Use the lowest effective starting dose when patient sensitivity, uncertainty, or a narrow therapeutic window warrants conservative titration.

Patient Education and Shared Decisions

Education should explain the treatment purpose, administration, expected response, important adverse effects, monitoring, and the patient’s role in the decision (NICE, 2015; de Vries et al., 1994).

• Explain the purpose of treatment and the expected time to benefit in plain language.
• Review how and when to take the medication, what to do after a missed dose, relevant food or substance interactions, storage, and any required technique.
• Separate common, manageable effects from serious findings that require urgent evaluation.
• Explain the monitoring plan and when the patient should expect follow-up, laboratory testing, or dose adjustment.
• Use teach-back to identify misunderstanding and document the decision when the patient declines or chooses among reasonable options. Treatment decisions should integrate the best available evidence, clinical expertise, and the patient’s values and preferences (NICE, 2015).

Monitor Effectiveness and Safety

• Define the outcome measure, safety measure, follow-up interval, and person responsible for reviewing results before treatment begins (de Vries et al., 1994).
• Passive monitoring relies on the patient to report response or problems. Active monitoring schedules assessment, laboratory testing, drug levels, or other measurements. Higher-risk therapy generally requires a more explicit active plan.
• At follow-up, assess benefit, adverse effects, adherence, access, interactions, and whether the diagnosis or therapeutic objective has changed (NICE, 2015).
• Continue, titrate, switch, deprescribe, or refer based on the balance of benefit and harm rather than continuing a medication indefinitely by default.

Common Prescribing Errors

• Treating a symptom without reconsidering the diagnosis when the expected response does not occur.
• Selecting a familiar medication without comparing contraindications, patient factors, monitoring burden, and current evidence.
• Starting therapy without defining when or how effectiveness will be judged.
• Labeling nonadherence as patient refusal without evaluating cost, regimen complexity, health literacy, adverse effects, competing priorities, and access.
• Adding medication to treat an adverse effect without first determining whether the original drug can be reduced, replaced, or stopped.

Related YourDNP Resources

• Pharmacokinetics
• Pharmacodynamics
• Pharmacoeconomics
• The APRN Prescriber Role
• Quiz: Foundations of Pharmacology

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References

de Vries, T. P. G. M., Henning, R. H., Hogerzeil, H. V., & Fresle, D. A. (1994). Guide to good prescribing: A practical manual. World Health Organization. https://iris.who.int/items/cfc95811-f8b8-4590-96fd-77726a647883

National Institute for Health and Care Excellence. (2015). Medicines optimisation: The safe and effective use of medicines to enable the best possible outcomes (NICE Guideline NG5). https://www.nice.org.uk/guidance/ng5

Woo, T. M., & Robinson, M. V. (2019c). Rational drug selection [PowerPoint slides]. F. A. Davis.