Drug Monitoring and Adherence

Digoxin

• Poorly absorbed from the GI tract, with different bioavailabilities for liquid and tablet formulations, requiring dose adjustments.
• Widely distributed in tissues, with a large volume of distribution (e.g., heart, kidney, liver).
• Mainly excreted unchanged, with a half-life of 30-40 hours in normal renal function.
• Therapeutic levels: 0.8-2 micrograms/L, with a likelihood of toxicity increasing progressively from 1.5 to 3 micrograms/L.
• Signs of toxicity: confusion, anorexia, nausea, vomiting, disturbance of color vision, and arrhythmia.
• Drugs that increase levels: amiodarone, clarithromycin, canagliflozin.
• Drugs that decrease levels: rifampicin, phenytoin, sulfasalazine.

Medication Adherence

• Adherence: the extent to which a patient's behavior matches agreed recommendations from the prescriber, emphasizing patient agreement and freedom to decide.
• Compliance: the extent to which a patient's behavior matches the prescriber's recommendations, with a focus on the prescriber's instructions.
• Concordance: a collaborative process between the clinician and patient to design a treatment regimen, focusing on the patient's behavior in taking medicines.
• Intentional non-adherence: when a patient decides not to follow treatment recommendations.
• Unintentional non-adherence: when a patient wants to follow treatment recommendations but faces practical problems.
• Only 16% of patients take their medicine as prescribed, with 55% unaware of incorrect usage and 45% intentionally non-adherent.

Barriers to Medication Adherence

• Explore the reason for non-adherence.
• Ask the patient what they know and believe about their medicines.
• Ask the patient if they understand their need for the medicine.
• Greater concordance leads to greater adherence and optimal medicine use.

Discharge Medication Service (DMS)

• Essential service since February 2021, aiming to reduce medication-related harm during hospital discharge.
• Collaborative effort between NHS trusts, community pharmacies, and PCNs.
• Focuses on high-risk medicines and patients.

Transfer of Care Around Medicines (TCAM)

• National initiative to connect hospitals with community pharmacies using the PharmOutcomes platform.
• Reduces unintentional changes or errors, leading to a decrease in avoidable harm and readmissions.

Other Ways to Follow Up Patients

• Examples include medication changes, medication reviews, and discussions around adherence.
• Record keeping is essential, including patient discussions, advice, and medication reviews.

Drug Monitoring

• Management of a patient's drug regimen through laboratory and physical tests to:
  • Optimize treatment
  • Reduce harm
  • Measure therapeutic effectiveness
  • Screen for and prevent adverse drug reactions
  • Assess patient compliance
• Examples of lab tests include monitoring tests, blood pressure, HbA1c, heart rate, liver function, renal function, full blood count, and chest x-ray.

Monitoring Individual Drugs

• Measure therapeutic effectiveness
• Screen for and prevent adverse drug reactions
• Assess patient compliance

Monitoring in Primary Care

• Structured medication reviews
• Confidential consultation between a GP/pharmacist/advanced nurse practitioner and a patient
• Aims to check the appropriateness of prescribed medications and help patients get the best out of their medicines
• Gives patients the opportunity to ask questions and raise concerns

Principles of a Medication Review

• All patients should have the chance to raise questions and highlight problems with medication
• Seek to improve or optimize the impact of treatment for an individual patient
• Undertaken in a systematic way by a competent person
• Any changes resulting from the review are agreed with the patient
• The review is documented in the patient's notes
• The impact of any change is monitored

Medication Review Types

• Type 1: Prescription review
• Type 2: Concordance and compliance review
• Type 3: Clinical medication review (holistic review, involving the patient, medical notes, and lab results)

Problems with Clinical Medication Reviews

• Which patients should be reviewed?
• How to ensure consistent reviews?
• Will patients want a medication review?
• Access to notes

Contents of a Medication Review

• The medication is appropriate for the patient's needs
• The medication is effective
• The medication is cost-effective
• Appropriate monitoring has been done

Monitoring in Secondary Care

• The point of admission: medicines reconciliation, review of therapeutic effects, and potential adverse effects
• During admission: daily ward round, review of patient's clinical state, monitoring of therapeutic effects, and potential side effects
• The point of discharge: ensure patient parameters are stable on newly prescribed medication, document further monitoring required in primary care