In an 89‑year‑old patient, how should dexamethasone be dosed, for how long, and what monitoring and precautions are needed?

Dexamethasone Dosing in an 89-Year-Old Patient

For an 89-year-old patient, start dexamethasone at 20 mg once weekly when used in combination regimens for multiple myeloma, or use reduced doses of 8-20 mg once weekly for frail elderly patients, with continuous monitoring for hyperglycemia, infections, and muscle weakness. 1

Initial Dosing Strategy

Low-dose dexamethasone is strongly preferred over high-dose in elderly patients aged 65 years and older due to significantly superior survival outcomes. 1

Specific Dosing by Indication

For multiple myeloma treatment in transplant-ineligible elderly patients:

• Standard starting dose: 20 mg orally once weekly when combined with lenalidomide (lenalidomide-low-dose dexamethasone regimen) 1
• For very frail patients >75 years: Further reduce to 8-20 mg once weekly, with subsequent titration based on response and tolerability 1
• This represents a dramatic reduction from the traditional 40 mg dosing used in younger patients 1

The ECOG E4A03 trial demonstrated that low-dose dexamethasone resulted in 91% overall survival at 2 years in elderly patients who did not proceed to transplant, compared to significantly worse outcomes with high-dose dexamethasone. 1

Route of Administration

Oral and intravenous dexamethasone are completely interchangeable with 1:1 dosing equivalence - 8 mg IV equals 8 mg oral 2

• Use oral route whenever gastrointestinal function is intact 2
• Reserve IV administration only for patients with nausea, vomiting, altered mental status, or impaired GI absorption 2

Duration of Therapy

Continuous therapy until disease progression is recommended over fixed-duration therapy for elderly patients with multiple myeloma. 1

Treatment Timeline

• Initial phase: Continue full-dose dexamethasone for the first year if tolerated well 1
• After one year: Consider dose reduction or elimination of dexamethasone while continuing lenalidomide 1
• The FIRST trial demonstrated that continuous lenalidomide-dexamethasone reduced risk of progression or death by 28% compared to fixed 18-month therapy 1

Monitoring Requirements

Essential Laboratory Monitoring

Monitor blood glucose levels closely, as hyperglycemia occurs in approximately 76% of elderly patients receiving dexamethasone. 1

Check for new infections regularly:

• Pneumonia and sepsis occur in 24-25% of elderly patients on dexamethasone 1
• Grade 3/4 infections occur in 20% of very elderly patients (median age 76 years) 1

Assess for muscle weakness at each visit:

• This is a common grade 3/4 adverse event in patients aged 66-90 years 1

Clinical Monitoring Parameters

• Thromboprophylaxis is mandatory - use aspirin or full anticoagulation for higher-risk patients, as deep venous thrombosis risk reaches 20% without prophylaxis 1
• Monitor for secondary primary malignancies during extended lenalidomide-dexamethasone therapy 1
• Assess functional status and frailty measures to predict excessive toxicity and early treatment discontinuation 1

Discontinuation and Tapering

For short courses ≤5 days (such as antiemetic regimens), dexamethasone can be stopped abruptly without tapering. 2

For prolonged use beyond 5 days at doses ≥8 mg/day:

• Reduce by 50% every 3-4 days until reaching 4 mg/day 2
• Then reduce by 2 mg every 3-4 days until reaching 2 mg/day 2
• Finally reduce by 1 mg every 3-4 days until discontinued 2
• Monitor for withdrawal symptoms (nausea, vomiting, loss of appetite) at each tapering step as indicators of possible adrenal insufficiency 2

Critical Precautions for Very Old Patients

Age-related renal dysfunction requires dose adjustment for lenalidomide (when used in combination), but NOT for dexamethasone itself. 1

Evaluate glomerular filtration rate before starting any regimen using the Cockcroft-Gault formula, as renal function is usually markedly depressed in very old individuals 3

Common pitfalls to avoid:

• Do not use high-dose dexamethasone (40 mg) in patients >65 years - this significantly worsens survival 1
• Do not assume IV route is superior when oral administration is feasible - this increases costs and hospital length of stay without improving outcomes 2
• Do not continue full-dose dexamethasone indefinitely - consider dose reduction or elimination after one year while maintaining lenalidomide 1
• Do not forget thromboprophylaxis - this is non-negotiable with immunomodulatory drug combinations 1

Frailty, falls, and abnormal medication sensitivity are more common in the last years of life and directly impact adverse drug reaction occurrence in 89-year-old patients. 3