Medications Work Differently In Older Adults


May 15, 2023


Medications in Older Adults

Research on the impact of medications is usually done on younger people. However, as we age our bodies react to drugs differently than when we were younger. As a result medications work differently in older adults.

Changes in the Body

As the body ages, changes can decrease the body’s ability to break down or remove certain medications from the system. This may mean that medications can stay in your body longer. So, an older adult may need a lower dose of the medication or a different medication that is safer.

Unique Needs of Older Adults

In most cases, older adults need lower doses of medications than younger adults. A healthcare professional should generally start with a low dose of a medication for older adults. Then they can slowly increase to the target amount to get the benefits and avoid side effects.

Some medications are less safe for older adults than others. Always work with your healthcare professional to use medications that are safe for your age.

When taking medications, it is important to make sure that:

  • The correct medication is prescribed for the correct condition
  • The medication is right for you, your age, and your conditions
  • You take the proper dose for the length of time your healthcare provider prescribes

Updated AGS Beers Criteria®

The American Geriatrics Society makes choosing medicines easier because it develops and updates the “AGS Beers Criteria®.” The AGS Beers Criteria® lists medications that may not be safe in older people. You can use the information when you talk to your healthcare professional about medications.  Beers List 2023 Revision, see pages 6-12.

Multiple Medical Conditions

Older adults often have several medical conditions. These conditions may affect how medications work in the body.

Medications used to treat one condition may also make another condition worse. For example, older adults with memory problems may have worse symptoms due to the medicines they take to treat other conditions. So, each healthcare professional needs to know about all your medical conditions and related medications. Your healthcare professionals also need to know if a medication makes any of your conditions worse.

Effects of Food and Beverages on Medications

Medications may be affected by the foods, drinks, supplements or herbal products, or other medications that you take.

For example, some antibiotics are not absorbed well when taken with foods, drinks, or medicines that contain calcium, magnesium, or iron. Antacids, vitamins, or dairy products contain these.

Also, certain drinks such as grapefruit juice can change how your body processes medicines. These changes can cause the medicine to build up in the body.

You can ask your pharmacist what foods, drinks, or supplements/herbals to avoid when you pick up your medications.

Medication Interactions

A medication interaction is a reaction between:

  • two (or more) medications, or
  • a medication and food, drink, supplement, or herbal product

A medication interaction can make a drug’s effect stronger, weaker, or cause harmful side effects.

An older person may be on multiple medications to treat different conditions. They may also use over-the-counter (OTC) medicines, vitamins, other supplements, or herbal products. The more of these you take, the greater the chances of having a medication interaction.

Let your healthcare provider and pharmacist know about all prescription and other medicines, supplements, and herbal products you use at home. They can check on medication interactions for you.

Other Factors

The following things can also affect medications:

  • Nicotine use
  • Caffeine
  • Alcohol
  • Diet
  • Changes in medical conditions, illness, and infections

Side Effects

Side effects of medications can hurt older adults and may reduce their ability to do daily activities. Older adults sometimes have the following side effects from their medications:

  • Headache and confusion
  • Dizziness and falls
  • Weight loss or weight gain
  • Changes in memory or ability to think and use information

Be sure to let your healthcare professionals know about any side effects, so they can find medications that may work better for you.


Many older adults cope with more than one medical condition at the same time. Often, having many health conditions means that older adults need more than one medication.

When older adults take five or more medicines, it is called “polypharmacy.” Using polypharmacy may increase medication interactions and cause harm. Side effects may get worse, and the medicines’ benefits can decrease.

Tell your healthcare professional about any side effects, such as having a fall or memory problems. Ask if the side effects could result from one or more of your medicines.

Keep Track of Medications

Many older adults get their medications from different healthcare professionals. It is important to always provide all your healthcare professionals a list of your current medications, including any OTC medicines, vitamins, supplements, or herbal products.

This can help prevent harmful side effects and decrease drug interactions.

Prescribing Cascade

A prescribing cascade happens when a side effect of one medication is mistaken for a new medical condition and is treated with another medication.

The prescribing cascade can lead to being prescribed more medications than you need. The cascade can also increase your risk of having more side effects and drug interactions. Polypharmacy increases the possibility of a prescribing cascade.

You can do the following to help prevent a prescribing cascade:

  • Bring a list of all medications you use to your healthcare visits.
  • Ask your healthcare provider to review all your medicines with you or necessity.
  • Before you get a new medication, ask if one of the medicines you are already taking might be causing the problem.


We hope this information is helpful to you in the important work you do as a family caregiver.
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