8.2 Prospective Drug Utilization Review (DUR) Requirements

8.2 Prospective Drug Utilization Review (DUR) Requirements

Core Legal Standard: Under OAC 535:10-9-1.2 and federal OBRA '90 (42 U.S.C. § 1396r-8(g)), a pharmacist—or a registered pharmacy intern under direct pharmacist supervision—must perform a prospective Drug Utilization Review (DUR) before dispensing each prescription (new or refill). The prospective DUR requires a thorough evaluation of the patient profile and medication order to identify potential drug therapy problems across seven statutorily defined clinical categories.

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1. Prospective vs. Retrospective DUR

Drug Utilization Review in pharmacy jurisprudence is divided into two distinct operational frameworks:

+------------------------------------------------------------------------------------------------+
|                       PROSPECTIVE VS. RETROSPECTIVE DUR COMPARISON                             |
+-----------------------+---------------------------------------+--------------------------------+
| Dimension             | Prospective DUR                       | Retrospective DUR              |
+-----------------------+---------------------------------------+--------------------------------+
| Timing:               | BEFORE the medication is dispensed    | AFTER the medication is filled |
| Responsible Party:    | Dispensing Pharmacist / Intern        | State Medicaid Board / PBM DUR |
| Scope of Review:      | Immediate patient profile & order     | Aggregate claims data & trends |
| Primary Objective:    | Prevent immediate harm / toxicity     | Identify systemic use patterns |
| Legal Requirement:    | Mandatory for every prescription fill | Periodic institutional reviews |
+-----------------------+---------------------------------------+--------------------------------+

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2. The Seven Core Clinical Domains of Prospective DUR

Under OAC 535:10-9-1.2, the pharmacist must examine the patient's electronic profile and current prescription for potential adverse outcomes within seven explicit clinical categories:

1. Therapeutic Duplication

• Definition: The concurrent prescribing and dispensing of two or more drugs from the same pharmacological or therapeutic class, resulting in cumulative toxicity without added clinical benefit.
• Clinical Examples:
  • Concomitant dispensing of lisinopril and losartan (dual renin-angiotensin-aldosterone system blockade increasing hyperkalemia and renal failure risk).
  • Concomitant use of celecoxib and ibuprofen (dual NSAID therapy increasing gastrointestinal ulceration and renal toxicity).

2. Drug-Disease Contraindications

• Definition: Clinical scenarios where a prescribed drug is known to exacerbate, destabilize, or worsen an existing diagnosed pathological condition.
• Clinical Examples:
  • Prescribing non-selective beta-blockers (e.g., propranolol) to a patient with severe reactive airway disease or asthma (bronchospasm risk).
  • Prescribing systemic NSAIDs to a patient with advanced chronic kidney disease (CKD stage 4/5) or active peptic ulcer disease.
  • Prescribing pseudoephedrine to a patient with uncontrolled, severe hypertension.

3. Drug-Drug Interactions (Including OTCs and Herbal Agents)

• Definition: Pharmacokinetic (absorption, distribution, metabolism, elimination) or pharmacodynamic conflicts between two or more co-administered medications.
• Clinical Examples:
  • CYP3A4 Inhibition: Co-prescribing clarithromycin (strong CYP3A4 inhibitor) with simvastatin (CYP3A4 substrate), causing massive increases in statin levels and severe rhabdomyolysis.
  • QTc Prolongation: Co-administering ciprofloxacin with amiodarone or sotalol, precipitating fatal Torsades de Pointes ventricular arrhythmias.
  • Pharmacodynamic Potentiation: Co-prescribing opioids with benzodiazepines or other sedative-hypnotics, leading to severe respiratory depression, coma, or death.

4. Incorrect Drug Dosage or Duration of Treatment

• Definition: Dosing regimens that fall outside accepted clinical practice guidelines, including subtherapeutic underdosing, supratherapeutic overdosing, excessive duration, or improper frequency.
• Clinical Examples:
  • Ketorolac (Toradol) systemic therapy prescribed for longer than 5 consecutive days (high risk of acute kidney injury and gastrointestinal bleeding).
  • Weight-based pediatric antibiotic dosing errors (e.g., amoxicillin/clavulanate overdoses).
  • Failure to adjust renally cleared medications (e.g., gabapentin, enoxaparin, novel oral anticoagulants) for a patient with documented renal impairment.

5. Drug-Allergy Interactions & Sensitivities

• Definition: Prescriptions ordered for medications to which the patient has a documented hypersensitivity, immune-mediated allergy, or high-risk chemical cross-reactivity.
• Clinical Examples:
  • Dispensing amoxicillin or cephalexin to a patient with a documented history of severe IgE-mediated anaphylaxis to penicillin.
  • Dispensing sulfamethoxazole/trimethoprim (Bactrim) to a patient with a confirmed sulfonamide antimicrobial allergy with Stevens-Johnson Syndrome (SJS).

6. Clinical Abuse, Misuse & Overutilization

• Definition: Inappropriate medication utilization patterns, premature refill requests, overlapping controlled substance prescriptions from multiple prescribers ("doctor shopping"), or excessive dosage escalation.
• Clinical Examples:
  • A patient requesting a refill for a 30-day supply of alprazolam or oxycodone on day 12 of therapy.
  • Multiple concurrent Schedule II opioid prescriptions written by different prescribers without mutual clinical coordination.

7. Drug-Food & Dietary Supplement Interactions

• Definition: Significant pharmacokinetic interference caused by dietary components, nutritional supplements, or nutritional states.
• Clinical Examples:
  • Ciprofloxacin or doxycycline co-ingestion with calcium-rich dairy products or iron/aluminum/magnesium antacids (chelation and failed absorption).
  • Consumption of grapefruit juice (intestinal CYP3A4 inhibitor) while taking oral cyclosporine or felodipine.

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3. Mandatory Patient Profile Maintenance Standards

To conduct a meaningful prospective DUR, the pharmacy must maintain an individualized, readily retrievable patient profile. Under OAC 535:10-9-1.2, the pharmacist must make a reasonable and diligent effort to obtain, record, and maintain:

+------------------------------------------------------------------------------------------------+
|                       MANDATORY PATIENT PROFILE DATA ELEMENTS                                  |
+------------------------------------+-----------------------------------------------------------+
| 1. Demographic Information:        | Full patient name, address, telephone number, DOB / age,  |
|                                    | and biological sex                                        |
| 2. Clinical History:               | Known disease states, chronic conditions, and diagnoses   |
| 3. Hypersensitivity Records:       | Known allergies, adverse drug reactions, idiosyncratic rxn|
| 4. Comprehensive Medication List:  | Complete record of all prescription drugs, devices, OTCs, |
|                                    | and herbal/dietary supplements reported by the patient    |
| 5. Pharmacist Clinical Comments:   | Pharmacist intervention notes, prescriber communications,  |
|                                    | and clinical rationale regarding resolved DUR conflicts   |
+------------------------------------+-----------------------------------------------------------+

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4. Conflict Resolution & Pharmacist Interventions

When a prospective DUR screening identifies a clinically significant problem, the dispensing pharmacist cannot simply bypass or ignore the automated computer alert. The pharmacist is legally required to resolve the issue using the following hierarchy of clinical actions:

1. Clinical Assessment: Review the patient's complete profile, laboratory parameters (if available), prescriber specialties, and medication administration history to determine the clinical severity of the alert.
2. Prescriber Consultation: Contact the prescribing practitioner to discuss the conflict, suggest evidence-based therapeutic alternatives, recommend dose adjustments, or verify clinical intentionality.
3. Patient Communication: Interview the patient or caregiver during counseling to gather additional clinical data (e.g., verifying whether a discontinued medication is still being taken, assessing compliance, or screening for symptoms).
4. Refusal to Dispense: If the prescription represents a clear and severe safety hazard, lacks a legitimate medical purpose, or if the prescriber cannot be reached to resolve a dangerous interaction, the pharmacist possesses the legal authority and Corresponding Responsibility to refuse to fill the prescription.

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5. Documentation and Record Retention Mandates

Whenever a pharmacist resolves a significant DUR alert or performs an intervention with a prescriber, comprehensive documentation is legally required under Oklahoma law:

• Intervention Notes: The record must reflect the identified issue (e.g., drug-drug interaction), the date and time of communication, the name of the prescriber or authorized agent consulted, the agreed resolution (e.g., dose reduced, duplicate drug discontinued), and the pharmacist's initials/identifier.
• Retention Mandate: All patient profile records, prospective DUR intervention logs, and prescription dispensing histories must be retained in a readily retrievable format for at least two (2) years from the date of the last entry.