Brief Answer:
She may be more sensitive due to age, or have a cytochrome deficiency

Detailed Answer:
Yes, your mother-in-law sounds quite sensitive. I have a two thoughts about her physical sensitivities:

1. Both children and elderly are known to be more sensitive to medications and can have "paradoxical reactions" where they have opposite reactions to what one would expect their medication would cause. For example, Benadryl is usually sedating but some people who are more sensitive may become agitated. This applies to not only prescription medications but reactions to the "active" ingredients in some herbal therapies too.

One way to address this is for medications to be started at a very low dose and to increase them very gradually. Sensitive people and the elderly may be able to tolerate medications better this way.

2. Some people have differing amounts of the cytochromes/enzymes that metabolize and break down medications or other substances. This can lead to erratic and unpredictable responses to the medications. People who have deficiencies of certain liver cytochrome P450 enzymes, for example, may have unwanted reactions (not true allergies) to many different medications that are metabolized by this liver cytochrome. There are other cytochromes that process many medications such as cytochrome 2D6A.

I am not aware of any casework of people in a class like her, but there are some research studies on people with specific cytochrome deficiencies.

Some thoughts:
You may want to ask a pharmacist to look up any medications she has reacted poorly to for which cytochrome/enzyme they are metabolized, and see if there is a pattern of a specific one. Then, future meds metabolized by that cytochrome should be avoided or used cautiously. Pharmacists are often willing to help with medication related questions if you are a customer of theirs, and if you give them time (days) to do this when they are not busy.

Cytochrome alterations are often genetic. I do not specifically know if a geneticist can help her by testing for cytochrome enzyme deficiencies but it may be something you want to explore.

Regarding whether she can self-medicate with more success, are you meaning try alternative treatments for her symptoms? Herbals, etc, are processed/broken down and used by the body by the same liver and kidney pathways, so she may run into sensitivities there too.

I hope this information helps. If you have more questions or clarifications please let me know.
Best regards,
Bonnie Berger-Durnbaugh, MD

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