Blog 21 –  Adverse Drug Reactions, Part II

Introduction

The prescribing of inappropriate medications for the elderly creates for them an unnecessary burden, physically and financially.  As noted in Blog 20, and further described here, prescribing of potentially inappropriate medications is one of several acknowledged reasons for adverse drug reactions (ADRs) in the older adult.  

ADRs are harmful and potentially life-threatening reactions dependent on medication use.  ADRs require readjustment or stoppage of the medication.  The elderly are especially sensitive to ADRs as a result of age changes that affect many aspects of drug handling by the body, comorbidities and multiple drug use (see Blog 20).  Prescribing of potentially inappropriate medications brings with it needless ADRs.  This blog will define inappropriate medications according to the Beers Criteria.  It will also discuss the importance of this topic and reasonable ways to avoid ADRs.

Potentially Inappropriate Medications – Origins

Slightly more than 30 years ago, JM Beers organized a panel of clinical experts to systematically categorize appropriate and inappropriate medications in nursing homes (Beers et al., 1991).  From this insightful investigation developed the Beers Criteria, a thoughtfully researched  and expertly evaluated presentation of drugs considered as inappropriate medications for the elderly.  Experts update the Beers Criteria every 3 years with the most recent update published in 2019 (see references).

Potentially Inappropriate Medications – Reasons for drug selection

Medications on the Beers Criteria are there for several reasons.  These are medications that

a)  on average should be avoided in the elderly due to data on age changes,

b)  are to be avoided in elderly with certain conditions,

c)  have low efficacy and hence the risks outweigh benefits and for which there are safer and more efficacious drugs,

d)  are known to interact poorly with commonly used essential drugs and

e)  require extremely careful dosing due to kidney disease

As with all advice on drug use, there are additional issues to consider.  Over time “inappropriate medications” on Beers Criteria became “potentially inappropriate medications”.  This recognizes the possibility that some patients may do well (efficacy in the absence of expected ADRs) with a drug considered inappropriate and, therefore, the caregiver/patient are the final arbiters.

Potentially Inappropriate Medications – Specific classes and drugs

Using medication data from Medicare Part D participants, Toth et al., (2022) reported that inappropriate medications prescribed most frequently fell into one of the following classes of drugs:  proton pump  inhibitors, benzodiazepines and antipsychotics.  These frequently prescribed potentially inappropriate medications are detailed below. Additional potential inappropriate medications (partial list) are presented in the schematic at the end of the blog.  

Proton Pump Inhibitors

Drugs classified as proton pump inhibitors act by blocking acid secretion in the stomach.  Thus, these drugs are useful in the treatment of acid-related disorders e.g. peptic ulcer, gastric reflux.  Drugs in this class are inappropriate for the elderly for several reasons:  Firstly, chronic use is associated with increased risk of bone loss. This would add to the presence of reduced bone density, common in the elderly.  As bone density decreases, the risk of fracture increases.  Fractures are costly, both financially and physically, limiting mobility and independence. Secondly, chronic acid suppression allows for overgrowth of harmful bacteria and use of proton pump inhibitors is associated with the onset of Clostridium difficile infection, a severe bacterial infection that is difficult to eliminate.  Omeprazole (Prilosec) is a proton pump inhibitor that is frequently prescribed.

Benzodiazepines

Drugs labeled benzodiazepines act in the brain to reduce anxiety and induce sedation.  As such they are anxiolytic and hypnotic drugs.  These drugs are inappropriate in the elderly because they hinder memory and additionally are associated with an increased risk of falls. Reduction of memory at any age is unwanted.    Increased risk of falls is highly associated with a fracture with serious consequences.  Additionally, these drugs are addictive.  Commonly prescribed benzodiazepines are alprazolam (Xanax), and lorazepam (Ativan),

Antipsychotics

Antipsychotics act on the brain to suppress psychosis.  These drugs are also sedating and associated with onset of abnormal muscles twitching.  Their use is inappropriate in psychosis associated with Parkinson’s Disease as they exacerbate the disease-dependent muscular dysfunction.  They are also inappropriate in individuals with dementia or cognitive impairment.  Since these drugs are sedating, they are inappropriate in individuals with a history of falls.  Commonly prescribed antipsychotics are quetiapine (Seroquel) and risperidone (Respirdal).

Future Steps

The prevalence of exposure in the elderly to potentially inappropriate medications varies between ~14% to 41% or more depending on the population under study.  Fortunately, the prevalence of prescribing potentially inappropriate medications has declined a few percentage points from 2013 to 2019 (Clark et al., 2020).  This is an encouraging start.  Additionally, there is effort by the medical community to  educate physicians, pharmacists, all prescribing care givers and patients on this issue.  This should further reduce prescribing of potentially inappropriate medications.

Common Sense Approach to Avoidance of ADRs

• Non pharmacological interventions should always be tried first (see Blogs 2,3,10,11).  Interventions e.g. exercise and diet are highly successful strategies to prevent and moderate diseases such as Type II  diabetes, hypertension (high blood pressure), and heart disease.

• Older adults taking medications should establish clear goals and endpoints with their physician and continually re-evaluate them.  Every patient needs to know exactly why the medication is prescribed and what to expect from it, that is, how to know if it is working and therefore, worth taking. 

• It is important to reduce polypharmacy (simultaneous use of more than 4 medications).  The higher the number of prescribed drugs, the greater the risk for ADRs.  Each patient and physician should review drugs frequently and endeavor to eliminate duplicates, and potentially inappropriate medications and keep only the essential drugs.

• In reduction of polypharmacy, the usage of some drugs is terminated.  Drug withdrawal should be a serious undertaking.  Dose reduction should always be as slow as possible, extending over weeks and months, thereby avoiding unnecessary ADRs.

• The actual drug dose is critical to avoiding ADRs.  It is common sense to start with the lowest dose possible and increase slowly, if at all.  The use of higher doses requires convincing justification.

Conclusions

Based on Beers Criteria, an updated assessment of potentially inappropriate medications for the elderly is available to prescribing caregivers and pharmacists.  Drugs on this list negatively interact with age changes in the elderly and hence are potentially inappropriate medications and are responsible for ADRs.  ADRs can be avoided if physicians as well as the patients are informed about the main causes of ADRs and how to prevent them.

References

2019 American Geriatrics Society Beers Criteria Update Expert Panel.   American Geriatrics Society 2019 Updated AGS Beers Criteria® for Potentially Inappropriate Medication Use in Older Adults.  J Am Geriatr Soc. 67(4):674-694, 2019.

Beers et al., Explicit criteria for determining inappropriate medication use in nursing home residents. UCLA Division of Geriatric Medicine Arch Intern Med.  151(9):1825-32, 1991.

Clark CM et al., Potentially Inappropriate Medications Are Associated with Increased Healthcare Utilization and Costs. J Am Geriatr Soc 68(11): 2542–2550, 2020.

Croke L. Beers Criteria for inappropriate mediation use in older patients: An update from the AGS. Am Fam Physician. 101(1):56-57, 2020.

Fernandes de Oliveira RMA et al., Potentially inappropriate medication use in hospitalized elderly patients. Rev Assoc Med Bras 68(6): 797-801, 2022.

Fralick M et al., Estimating the Use of Potentially Inappropriate Medications Among Older Adults in the United States. J Am Geriatr Soc. 68(12):2927-2930, 2020.

Toth JM et al., Prescribing trends of proton pump inhibitors, antipsychotics and benzodiazepines of Medicare part d providers. BMC Geriatrics  22:306-321, 2022.

Steinman MA. How to Use the AGS 2015 Beers Criteria – A Guide for Patients, Clinicians, Health Systems, and Payors.  J Am Geriatr Soc. 63(12): e1–e7, 2015..