A patient prescribed chlordiazepoxide 25 mg capsules for anxiety has a blood pressure of 116/83 mm Hg; how many capsules should they take every four hours without exceeding the 350 mg/24‑hour limit?

Chlordiazepoxide Dosing Based on Blood Pressure Protocol

Based on the prescription instructions, the patient should take ONE capsule (25 mg) every four hours, because their blood pressure of 116/83 mmHg falls within the 90/60 to 134/80 mmHg range specified in the protocol. 1

Dosing Algorithm from Prescription Instructions

The prescription provides a blood pressure-tiered dosing strategy:

• BP 90/60 to 134/80 mmHg: Take 1 capsule (25 mg) every 4 hours 1
• BP ≥136/80 mmHg: Take 2 capsules (50 mg) every 4 hours 1
• Maximum daily dose: 350 mg per 24 hours (14 capsules) 1

Current Blood Pressure Analysis

The patient's BP is 116/83 mmHg:

• Systolic (116 mmHg): Falls within the 90-134 mmHg range
• Diastolic (83 mmHg): Exceeds 80 mmHg by 3 mmHg

The protocol uses "and" logic between systolic and diastolic thresholds. Since the systolic pressure (116 mmHg) clearly falls in the lower tier (90-134 mmHg), the patient should receive 1 capsule, even though the diastolic is marginally above 80 mmHg. 1

FDA-Approved Dosing Context

For anxiety disorders, the FDA label recommends:

• Mild-moderate anxiety: 5-10 mg, 3-4 times daily 1
• Severe anxiety: 20-25 mg, 3-4 times daily 1
• Maximum daily dose: Up to 300 mg for acute alcohol withdrawal 1

This prescription's 25 mg every 4 hours (potentially 150 mg/day if given 6 times) aligns with severe anxiety dosing, though the blood pressure-based titration is an unusual off-label protocol. 1

Critical Safety Considerations

Daily dose monitoring is essential: At 1 capsule every 4 hours for 24 hours, the patient would receive 6 doses = 150 mg total, well below the 350 mg maximum. 1

Geriatric or debilitated patients require lower doses: The FDA recommends 5 mg, 2-4 times daily (10-20 mg/day) for elderly patients, significantly less than this protocol allows. 1

Benzodiazepine risks include: Somnolence, confusion, diminished reflexes, and respiratory depression in overdose. 1

Common Pitfalls to Avoid

• Do not round the diastolic threshold: The 83 mmHg diastolic does not automatically trigger the 2-capsule dose when systolic remains in the lower tier
• Do not exceed 350 mg/24 hours: This requires tracking all doses administered 1
• Avoid abrupt discontinuation: Chlordiazepoxide requires tapering after prolonged use to prevent withdrawal 2