Why was a medication given?

Understanding Why a Medication Was Prescribed

Primary Approach to Determining Medication Rationale

The most reliable method to determine why a medication was given is to directly review the prescriber's documentation and obtain a complete medication history from both the patient and their medical records, as medication discrepancies and lack of awareness of drug indications are extremely common in clinical practice. 1, 2, 3

Common Barriers to Understanding Medication Rationale

Prescriber-Patient Communication Gaps

• More than 13% of patients in primary care do not know the indication for at least one of their prescription medications, with cardiovascular medications being the most commonly misunderstood 2
• Lack of knowledge is significantly more prevalent in patients who are older, Black, or have a high school education or less 2
• Between 64% and 92% of patient-reported medical histories are absent from prescribers' documentation, depending on the condition 3

Documentation and Reconciliation Failures

• Medication reconciliation failures occur at every transition of care and are particularly problematic in patients with complex regimens 1
• Prescribers are frequently unaware of previous medical histories that patients report, especially when there is less frequent patient-prescriber contact, prescription by a specialist, or no recent specialist consultation 3
• Medication discrepancies can be classified as: no-longer taking, not in record, dosing issues, or formulation differences 1

Systematic Approach to Identifying Medication Indication

Step 1: Review All Available Documentation

• Examine the original prescription order and any accompanying clinical notes 1
• Check hospital discharge summaries, rehabilitation facility records, and emergency department visits 1
• Review laboratory results that may indicate the condition being treated 1

Step 2: Obtain Comprehensive Medication History

• Ask the patient to retrieve all medication bottles and state the reason they take each medicine 2
• Document all currently and recently prescribed drugs, previous adverse drug reactions including hypersensitivity reactions, any over-the-counter medications including herbal or alternative medicines, and adherence to therapy 4
• Identify which specific medication was started, whether it was tapered or stopped abruptly, and previous psychiatric or medical history 5

Step 3: Consider Common Prescribing Patterns and Errors

Inappropriate Dosing as a Clue

• Inappropriate prescribing occurs in 8.4% to 28.9% of hospitalized patients, with common rationales including history of bleeding, concurrent antiplatelet use, frailty, advanced age, and fluctuating renal function 1
• Underdosing is the most common prescription error (4.7% to 26.1% of patients), often due to "blindly continuing home dose" or prescribing an erroneous dosage 1

Gender-Related Prescribing Patterns

• Women receive antidepressants 1.8 times more frequently than men and tend to receive suboptimal doses of guideline-recommended medications 6, 7
• Approximately 10-11% of women aged 18-24 years receive antidepressant or antianxiety medication prescriptions 6

Common Pitfalls and How to Avoid Them

Mistaking Withdrawal for New Pathology

• Paresthesias, anxiety, and memory impairment are classic withdrawal symptoms from antidepressants, not typical presenting features of brain tumors 5
• Withdrawal symptoms typically emerge within 24-48 hours of discontinuation, include prominent physical symptoms, and resolve with medication reinitiation 5
• When brain tumors cause psychiatric symptoms, they present with red flag features including new-onset symptoms, progressive worsening over days to weeks, focal neurological deficits, headaches that worsen with position or Valsalva, and seizures 5

Overlooking High-Risk Medication Combinations

• Patients with chronic coronary syndrome receiving oral anticoagulation who are also prescribed aspirin have significantly higher risks of cardiovascular events, death, and major bleeding 8
• The addition of aspirin to oral anticoagulation led to a 53% higher risk of cardiovascular events and a 3.35-fold higher risk of major bleeding 8

Missing Medication-Related Pathology

• Elevated phosphorus levels may result from sodium phosphate enema use rather than dietary noncompliance, leading to inappropriate escalation of phosphate binders 1
• Constipation in patients on opioids requires a bowel regimen; failure to continue this at discharge leads to emergency department visits 1

Role of Pharmacists in Clarification

Pharmacists are significantly better at taking accurate medication histories than physicians or nurses and reduce prescription errors, adverse drug reactions, and costs 4

• In acute hospital admissions, pharmacist involvement reduces transcription errors and improves medication reconciliation 4
• Electronic prescribing may reduce some errors but still depends on an accurate medication history 4

When Clinical Context Suggests Specific Indications

Cardiovascular Medications

• Patients lack knowledge of cardiovascular drug indications more frequently than other medication classes (OR 1.50) 2
• Amlodipine is commonly prescribed for hypertension, chronic stable angina, vasospastic angina, or documented coronary artery disease 9
• Gender-specific adverse effects occur more frequently in women, including edema (14.6% vs 5.6% in men) and flushing (4.5% vs 1.5% in men) 9

Medications Associated with Dependence

• Approximately 50% of patients prescribed antidepressants, opioids, gabapentinoids, benzodiazepines, or Z-drugs have been on them continuously for at least 12 months 1
• Only 24.0% of young adults receiving antidepressants were on them continuously for over 12 months, the lowest percentage of any age group 6