Medication management important for patients over 65
Patients over 65 years of age take an average of six to eight prescriptions a day. Often, these patients take additional over-the-counter drugs – which they may or may not mention to their doctors, believing that these over-the-counter drugs are not medications.
Elderly patients are twice as susceptible to adverse drug reactions as younger patients. Errors in administration may also occur with drugs similar in size, shape and color because of vision problems. Understanding a few medical concepts can help patients and caregivers become aware of the realities and seriousness of taking medications.
Two important medical concepts are pharmacokinetics and pharmacodynamics. Pharmacokinetics involves knowledge about absorption from the gastrointestinal tract, duration of drug action, distribution in the body and method of excretion. Pharmacodynamics is the knowledge about the action of the body site. All of these functions are affected as the patient becomes older. The dosage for a younger individual may not be the same as for an older person. The major body changes that require drug consideration are body composition, drug distribution, metabolism and excretion.
As a person becomes older, there is more body fat and less lean muscle. Certain drugs stored in fat will have a longer duration of action. Liver function decreases with age primarily due to diminished enzyme function and diminished blood flow. As a result, drug dosage may have to be decreased. In addition, kidneys are responsible for the excretion of many drugs. However, excretion by the kidneys is highly variable and differs from person to person – even those of the same age. There are also many acute and chronic illnesses that will impair kidney function, so a maintenance medication dosage may require an immediate change.
Common drugs that require extreme care with selection and dosage include hypnotics (sleeping medications), sedatives, tranquilizers, antipsychotics and analgesics. The dosages for nonsteroidal anti-inflammatory drugs (including over-the-counter ibuprofen and naproxen) have to be reduced and often entirely avoided, among others. The antidiuretic hormone decreases excretion of water from the kidney, and in the elderly, there is ineffective suppression of this hormone. Some drugs cause increased secretion of the antidiuretic hormone, and although doctors often recommend to drink plenty of liquids, liquid intake may have to be restricted.
Elderly patients need to start slow and go slow with their medications. Minimizing the number of drugs is the key to effective management, and patients should bring all of their medications to each physician’s appointment.
E. David Kirk, M.D., specializes in internal medicine and geriatrics with Kansas Physician Group.
This story was originally published September 4, 2015 at 6:37 PM with the headline "Medication management important for patients over 65."