BASIC · EP 09 · AGING
Before You Listen
Episode Setup
- Topic in one line: the downstream consequences of the physiologic decline mapped in Part 1, including treating the osteoporotic skeleton, the aging lung and age-adjusted oxygenation, pharmacokinetics beyond the kidney, distinguishing normal cognitive aging from dementia, sleep architecture and motor-learning consolidation, and falls plus the geriatric syndromes of frailty and delirium.
- Prerequisites: Part 1 of BASIC-09 (sarcopenia with selective type 2 fast-twitch fiber loss, postmenopausal trabecular-first bone loss, isolated systolic hypertension, baroreceptor dysfunction, chronotropic incompetence, the hidden estimated glomerular filtration rate (eGFR) of a sarcopenic patient); basic pharmacology vocabulary (volume of distribution, protein binding, phase 1 and phase 2 hepatic metabolism).
- Runtime: approximately 42 minutes for Part 2.
Vignette. A 78-year-old woman is admitted to inpatient rehabilitation three days after open reduction and internal fixation of a right intertrochanteric hip fragility fracture. Her dual-energy X-ray absorptiometry (DEXA) scan showed a T-score of -3.2 at the lumbar spine. On admission she is started on alendronate 70 mg weekly, calcium 1,200 mg daily, and vitamin D 800 international units (IU) daily. On rehabilitation day 4 the night-shift resident notes she has been awake since 3 AM and adds zolpidem 5 mg at bedtime for “sleep hygiene.” By morning the patient is somnolent, inattentive, confidently insists she had breakfast with her late husband, and on therapy fails the timed up and go (TUG) at 17 seconds. Her serum 25-hydroxyvitamin D (25-OHD) returns at 22 ng/mL.
Identify the four discrete errors this team made: (1) what specific administration rule alendronate requires and what happens when it is violated, (2) which physiologic 25-OHD target she has not yet reached and why that level matters for both bone and balance, (3) what acute cognitive syndrome she now has, how it differs from dementia, and which validated bedside instrument confirms it, and (4) which Beers-listed drug class contributed to her presentation.
(Answer at the end of this chapter)
Section 1: Treating the Osteoporotic Skeleton
Bottom line: osteoporosis is treated on three concurrent tracks: pharmacologic inhibition of resorption, supplementation, and a physiologic target for vitamin D. First line is an oral bisphosphonate (alendronate), taken on an empty stomach with a full glass of plain water, upright for at least 30 minutes after the dose. Escalation is intravenous zoledronic acid yearly or subcutaneous denosumab every 6 months. Calcium 1,000-1,200 mg/day plus vitamin D 800-1,000 IU/day, target serum 25-OHD ≥ 30 ng/mL, a threshold that matters for both calcium absorption and independent muscle and balance effects.
Part 1 ended with the vignette patient at a DEXA T-score of -3.0 with an intertrochanteric fragility fracture. The diagnostic logic is unchanged. Osteopenia is a T-score between -1.0 and -2.5; osteoporosis is -2.5 or lower. But a fragility fracture clinically defines osteoporosis regardless of the T-score. The fracture is mechanical proof that bone has failed, and the scanner is a downstream confirmation tool, not the diagnostic gate.
The first-line pharmacologic intervention is an oral bisphosphonate, prototype alendronate. Alendronate inhibits osteoclasts, halting further withdrawals from the trabecular calcium bank described in Part 1, and the remodeling equation tips back toward formation. The drug is mechanically effective, but it carries a strict administration protocol because the drug itself is caustic to the esophageal mucosa. If the pill lodges or the patient lies back down within minutes of swallowing, the result is esophagitis, ulceration, or perforation. The aging esophagus has slowed peristalsis, a lax lower sphincter, and frequent swallowing dysfunction, all of which raise the probability of mucosal damage. The protocol is non-negotiable: take alendronate on an empty stomach, with a full glass of plain water (not coffee, not juice), and remain completely upright for at least 30 minutes after the dose. The 30-minute window keeps gravity working with the lower esophageal sphincter and against reflux.
Pharmacology only halts withdrawals; it does not deliver raw materials. Secondary prevention runs in parallel: calcium 1,000-1,200 mg/day and vitamin D 800-1,000 IU/day, tied to a physiologic target of serum 25-hydroxyvitamin D (25-OHD) ≥ 30 ng/mL. The 30 ng/mL threshold matters for two distinct reasons, one of the most testable points in geriatric pharmacology. First, intestinal calcium absorption depends on vitamin D; without it, supplemental calcium is partially excreted unabsorbed. Second, vitamin D directly improves muscle fiber function and balance through receptors on skeletal muscle. A patient on a bisphosphonate whose 25-OHD sits at 18 ng/mL is treated and undertreated simultaneously: bone protected, balance still failing.
When oral alendronate cannot work in real life, whether from intolerance (dyspepsia, reflux, esophagitis), contraindication (stricture, achalasia, recent upper gastrointestinal surgery), or inadequate response (documented further loss or new fracture on therapy), escalation to non-oral therapy is mandated. Zoledronic acid is a potent intravenous bisphosphonate given once annually, bypassing the esophagus. Denosumab is a monoclonal antibody injected subcutaneously every 6 months, acting through RANKL inhibition rather than direct osteoclast poisoning. Either is a reasonable next step.
::: {.callout-important}
## High Yield — Osteoporosis Treatment
- Diagnosis trigger: T-score ≤ -2.5 at hip or lumbar spine OR any fragility fracture (fall from standing height). The fracture overrides the scan.
- First line: oral bisphosphonate (alendronate). Empty stomach, full glass plain water, upright ≥ 30 minutes to prevent esophageal injury.
- Supplementation: calcium 1,000-1,200 mg/day, vitamin D 800-1,000 IU/day, target serum 25-OHD ≥ 30 ng/mL.
- Escalation when oral fails: IV zoledronic acid yearly OR subcutaneous denosumab every 6 months.
- Vitamin D does double duty: intestinal calcium absorption AND direct muscle function and balance. It is a fall-prevention drug as much as a bone drug. :::
Board Trap — The Patient Who Lies Back Down
The trap is the elderly patient on alendronate who develops new-onset dysphagia and substernal chest pain weeks after weekly therapy began. The reflex answer is empiric proton pump inhibitor. The right answer is non-adherence to the upright-with-water protocol producing alendronate-induced esophageal ulceration. The fix is to switch routes to IV zoledronic acid or subcutaneous denosumab, not to layer acid suppression on top of continued unprotected oral dosing.