When more pills bring the fall — the five- and six-drug thresholds

Adverse effects begin rising at five drugs. Falls begin rising at six. What the Japanese Ministry of Health tells us, and what to do next.

Do you take it for granted that the number of pills multiplies as we age? Around me, five or six prescriptions in a single elderly patient is nothing unusual. But more pills are not more safety. When the number climbs, hidden trapdoors open. This piece is about where those thresholds sit.

Adverse effects rise almost linearly with the number of drugs

Japan’s Ministry of Health, Labour and Welfare (MHLW) is unambiguous: adverse drug events increase in near-linear proportion to the number of medications prescribed (MHLW, Guidelines for the Appropriate Use of Medications in Older Adults — General Volume, May 2018).

One threshold sits at six drugs. A study led by Dr. Taro Kojima at the University of Tokyo found a clear jump in adverse drug events once six or more medications were on board (Kojima et al., Geriatr Gerontol Int, 2012, cited as the primary source in the MHLW guideline).

The threshold for falls sits slightly lower. The same research group reported that unsteadiness and falls begin rising once five or more medications are prescribed (same guideline and Kojima et al., 2012). Five and six — those are the two numbers I keep in the back of my mind.

Why does the pill count climb?

One reason is what clinicians call the prescribing cascade. A side effect from drug A is misread as a new disease, and drug B is added on top. The MHLW guideline explicitly warns about this loop.

The second reason is fragmented care. Internal medicine adds a pill. Orthopedics adds another. Dermatology adds a third. With no single doctor holding the whole picture, medications quietly stack.

The numbers reflect reality. MHLW’s Statistics of Medical Care Activities in Public Health Insurance (2016) show that among Japanese aged 75 and over, 40.1% were on five or more medications, and 24.8% were on seven or more. This is not somebody else’s problem.

Never re-tune your prescriptions alone — do it with your doctor

In recent years, deprescribing — carefully tapering unnecessary medications — has drawn increasing attention. It is not, however, a panacea. A 2024 BMJ review found that just over half of deprescribing interventions produced better results than usual care on at least one outcome (Reeve et al., BMJ 2024;385:e074892). In other words, the effect depends on the specifics.

That is exactly why stopping a medication on your own is dangerous. Some drugs cause rebound illness if withdrawn abruptly. Whether they can be reduced is a conversation to have with your regular physician. A short preparation helps:

• Consolidate all prescriptions into a single medication booklet, and show it all at once.
• Don’t forget over-the-counter medicines and supplements.
• Describe any unsteadiness, falls, or memory changes concretely.
• Ask, out loud, “Are there any medications we could consider reducing?”

How many pills are stacked in your medication booklet today? At your next visit, why not sit with your doctor and look at the number, together?