Management of chronic pain in elderly, frail patients: finding a suitable, personalized method of control

Figures & data

Table 1 Physiologic changes with aging and its effects

System	Changes	Effect	Effect of drug use
Gastrointestinal	Altered secretions	Altered drug absoption	Altered oral bioavailability
	Decreased blood flow	Altered bioavailability
	Altered motility	Altered transit time
	Altered absorptive surface
Liver	Small liver mass	Decreased serum albumin	Increased bioavailability
	Reduced hepatic blood flow	Decreased metabolism of drugs	Higher toxicity risk
	Decreased hepatic enzymes	by 30%–40%
	(oxidation and cytochrome p-450)
	Decreased protein synthesis
	Decreased regeneration rate
Cardiac	Decreased cardiac index	Rapid and high drug peak	Higher toxicity risk
Renal	Reduced size	Decreased renal elimination	Required dose adjustment
	Decreased renal blood flow
	Reduced renal function (gfr),
	1% per year after age 50
General	Increased body fat	Increased volume of distribution	Delayed elimination and onset
	Decreased body water	for lipophilic medication	of drug of action
		Increased plasma concentration of hydrophilic drugs	Higher frequency of side effects
Nervous system	Decreased cerebral blood flow	Decreased descending inhibitory	Increased pain with noxious stimuli
	Neuronal loss/atrophy	pain control and altered	Altered response to pain
	Decreased synthesis of neurotransmitters Decreased opioid receptor density	pain processing
Muscle	Decreased muscle mass	Decreased functioning

Abbreviation: gfr, glomerular filtration rate.

Figure 1 Management of pain in frail older adults.

Abbreviation: NSAID, nonsteroidal anti inflammatory drug.

Table 2 Opioid equianalgesic conversion table

	Elimination	IV equivalent to IV morphine	PO equivalent to IV morphine
	(t½) in hours	10 mg (single dose)	10 mg (single dose)
Morphine	2–4	10 mg	20–60 mg
Fentanyl	4	100 mcg	N/A
Hydrocodone	4	N/A	30–40 mg
Oxymorphone	2–3	1	10
Hydromorphone	3	2 mg	10 mg
Methadone*	20–120	10 mg	10–20 mg
Oxycodone	3	N/A	20–30 mg

Notes

* very long elimination time causes methadone to accumulate over many days.

Abbreviations: IV, intravenous; PO, oral; N/A, not applicable.