Age and gender-related risk factors you should know
Did you know that people 65 and older have 2-3 times as many adverse drug events as younger adults?
Though they make up 13% of the population, older adults consume over 1/3 of all prescription drugs in the US. Chronic conditions such as heart disease, diabetes and high blood pressure often coexist and require a number of drugs to treat. The average older adult took 8.4 drugs a month, according to one University of Florida College of Pharmacy study. Medication for these chronic illnesses are generally taken long-term, often for the rest of life. With all these drugs and other over the counter remedies, it's much likelier that you might suffer from drug-related problems.
Medication use is a particular issue of concern for women considering that women 65 and older have the highest prevalence of medication use. 23% took 5+ medications, compared to 7% of 18 year olds and older who took 5+ medications. 12% of older women took 10+ medications.
24.6% of older women used at least 1 abusable prescription drug, compared to 17.7% of older men, according to the Medicare Current Beneficiary Survey. Women are more likely to consume psychoactive prescriptions such as opioid analgesics, benzodiazepines and anti-depressants. They are more vulnerable to sedative effects and cognitive impairment.
Because of physiological changes that take place as you age, drugs affect your body differently than they did when you were younger. Hormonal issues related to menopause and smaller body size affect how drugs are absorbed by women's bodies.
In general, metabolism and elimination slows down as you grow older, which means that drugs stay in your body longer. More specifically, the decrease in the percentage of water retained within the body means that we have a higher blood level of water-soluble drugs, such as alcohol. An example of a water-soluble drug is digoxin. This happens because most of the body's water is stored in muscles, but muscle tone decreases with age so there's more water circulating in the body. Conversely, the percentage of body fat increases, so fat-soluble drugs stay in the body longer and continue to exert their effects for longer than originally intended. Such fat-soluble drugs include barbituates, Thorazine and Valium.
Other factors that affect drug metabolization include diet, alcohol consumption, sleep and weather conditions such as humidity and high heat.
How does age change drug metabolization?
The liver, the kidneys and the intestines are the key sites of drug metabolization. Absorption during digestion tends to decrease, the stomach empties out chemicals and nutrients more slowly. This can lead to delayed drug action as well as a higher risk of ulcers.
The liver is the next stop; here, drugs are rendered water-soluble so that can then be excreted; with age, however, blood flow to this organ decreases and thus reduces blood flow there. Drugs such as nitrates, beta blockers, hydralazine and tricyclic antidepressants pass through and limits blood flow to the liver, so the amount that subsequently remains in the bloodstream is higher than it ought to be.
The kidney eliminates drugs, but this organ experiences some of the most dramatic age-related changes. It shrinks while its blood flow decreases, thus decreasing its filtering capacity. Such impairment slows down the elimination of water soluble drugs such as digoxin, some antibiotics, hypotensive agents and chlorpropamide. This can make you more susceptible to adverse drug reactions as they remain in the blood stream longer than they should.
Older adults seem to be more sensitive to certain drugs or suffer from side effects of other drugs that younger people don't experience at that same dosage. For example, the sedative and anti-anxiety drug Valium lasts 3 days in a 24-year-old's body, but 3 weeks for an 80-year-old. Older patients taking Valium should start off in smaller doses to avoid extreme side effects.
Sources:
Kaufman, D.W. et al. Recent patterns of medication use in the ambulatory adult population of the United States: the Slone survey. Journal of the American Medical Association, 2002; 287(3):337-344.
Simoni-Wastila L et al. National estimates of exposure to prescription drugs with addiction potential in community-dwelling elders. Substance Abuse. 2005;26(1):33-42.
Disclaimer:
Please note that though educational in nature, this website does not substitute for professional medical advice and should not be used as a sole guide for making decisions. Medications are constantly being developed and tested for their long term effects, so the information provided here should not be assumed to be the most current. When in doubt, always talk to your doctor or pharmacist. If you or a loved one are experiencing a health emergency, call 911. I avow all legal responsibility for your outcome.
