Elderly medication effects

Starting with a standard TCA such as imipramine, a typical dose is 25 mg three times daily. Dose may be increased by 25 mg every 2 or 3 days, as tolerated, and can usually be increased to 150 mg per day by the end of the first week in healthy adults. The elderly, medically compromised, those hypersensitive to side effects, or those with associated panic disorder may require lower doses and more gradual increases (see discussion in Chapter 6). 

Vigilance for drug-drug interactions is required because of the greater number of medications prescribed to elderly patients and enhanced sensitivity to adverse effects. Pharmacokinetic interactions include metabolic enzyme induction or inhibition and protein binding displacement interactions (e.g., divalproex and warfarin). Pharmacodynamic interactions include additive sedation and cognitive toxicity, which increases risk of falls and other impairments. 

Antihistamines such as diphenhydramine are known for their sedating properties and are frequently used over-the-counter medications (usual doses 25-50 mg) for difficulty sleeping. Diphenhydramine is approved by the FDA for the treatment of insomnia and can be effective at reducing sleep latency and increasing sleep time.43 However, diphenhydramine produces undesirable anticholinergic effects and carryover sedation that limit its use. As with TCAs and BZDRAs, diphenhydramine should be used with caution in the elderly. Valerian root is an herbal sleep remedy that has inconsistent effects on sleep but may reduce sleep latency and efficiency at commonly used doses of 400 to 900 mg valerian extract. Ramelteon, a new melatonin receptor agonist, is indicated for insomnia characterized by difficulty with sleep onset. The recommended dose is 8 mg at bedtime. Ramelteon is not a controlled substance and thus may be a viable option for patients with a history of substance abuse. 

The decrease in the ability of the aging body to respond to baroreflexive stimuli can result in very serious consequences for elderly patients [115-117]. Because of this decrease in sensitivity and the decreased cardiac output witnessed in elderly patients, they are predisposed to the effects of orthostatic hypotension that can occur when one is taking antihypertensive medication (e.g., prazosin). Indeed, the fact that elderly persons are prone to accidental falls may be due to this change in sensitivity [115-117]. 

Vision. Many people experience visual decline as they age (Fig. 3) [135]. Impaired vision may also hinder one s ability to self-administer medication. Listed in Table 10 are some of the effects that are associated with impaired vision in the elderly. Some of the processes of self-administration that are affected by impaired vision are as follows (a) the ability to accurately measure liquids (b) the ability to correctly read instructions and (c) the ability to differentiate between various types of medications (both the labeling of these drugs and their physical characteristics) [137,151-153],... 

Liquids and Suspensions. Most liquid formulations are not packaged in unit-dosage form. Therefore, before administration, the proper amount of medication to be taken for each dose must be measured. This additional requirement may compound any difficulties a patient may have in following a prescribed schedule. Patients suffering from visual impairment, arthritis, or tremors associated with neurological disorders are particularly likely to become frustrated with this type of formulation. Visual impairments make it difficult, if not impossible, for many elderly patients to measure the prescribed amounts of medication accurately. Impaired dexterity, owing to tremors or arthritis, may have effects on a patient s ability to hold both a spoon and a bottle at the same time while pouring out the desired amount of liquid. 

Some healthy elderly may not be very affected by pharmacological alterations whereas others have become very susceptible to adverse effects of drugs. It is especially important for elderly patients that pharmacotherapy is individualised. With knowledge of expected physiologic changes with aging, decisions should be based on the individual patient s disease and concomitant medications. 

All drugs may cause adverse drug reactions (ADRs). These adverse effects are either unpredictable (hyper-sensitivity) or dose-depending. The risk of ADR is increased for several reasons in the elderly. The physiological alterations, the high number of medications and concomitant diseases increase the risk of ADR. This is further... 

As health-care professionals we need to identify and solve the problem together with the patient, and we need to do it in a rational and cost-effective way. For a practitioner this is not easy based on the rapidly expanding progress within the medical area, increasing demand from patients, and the manipulation of information from various interests in the field. First we need drugs and other treatments with documented effects (efficacy) in the elderly. Then we need to select the most appropriate drug for the individual patient. The latter is complicated and evidence-based medicine (EBM) has been suggested as the method. Finally we need to communicate with the patient and establish a partnership (concordance). 

Klotz U, Avant GR, Hoyumpa Aet al. (1975) The effects of age and liver disease on the disposition and elimination of diazepam in adult man. J Clin Invest 55(2) 347-359 Kompoliti K and Goetz CG (1998) Neuropharmacology in the elderly. Neurol Clin 16(3) 599-610 Lanctot KL, Best TS, Mittmann N et al. (1998) Efficacy and safety of antipsychotics in behavioral disorders associated with dementia. J Clin Psychiatry 59(10) 550-561 Landi F, Onder G, Cesari M et al. (2005) Psychotropic medications and risk for falls among community-dwelling frail older people an observational study. J Gerontol A Biol Sci Med Sci 60(5) 622-626... 

Finally be aware of the fact that diseases in the upper part of the gastrointestinal tract are common in the elderly and can cause severe complications and even be fatal. Drugs that are often used in the elderly due to chronic diseases with inflammation and pain are often the cause of gastritis, peptic ulcers and hiatus hernia. The risks of medication side effects as a reason for the problem must be taken into account when treating elderly for peptic ulcers and stomach pain. 

Medications for symptomatic relief from vertigo consist of antiemetics, benzodiazepines and antihistamines. They are all mostly aimed at the psychological consequences of dizziness and can all have highly unfavourable side effects, for example, sedation, anticholinergic effects and insomnia. The psychological consequences of dizziness in elderly should rather be treated with information about the condition, supportive help actions and increased social activities, than with drugs. 

The risks of medication side effects must be taken into account when treating elderly for peptic ulcers and stomach pain... 

---