Older Adults on SSRIs: How to Prevent Hyponatremia and Falls

Every year, thousands of older adults start taking SSRIs to manage depression or anxiety. These medications work well for many, but they come with hidden dangers-especially for people over 65. Two of the most serious risks? Hyponatremia and falls. Both can turn a simple prescription into a life-altering event. And the scary part? Many of these cases are preventable.

What Is Hyponatremia, and Why Does It Happen with SSRIs?

Hyponatremia means your blood sodium level is too low-below 135 mmol/L. Sodium helps control fluid balance in your body. When it drops, water builds up in your cells, including brain cells. In older adults, this can cause confusion, dizziness, weakness, and loss of balance. All of these make falls more likely.

SSRIs trigger hyponatremia by causing something called SIADH-Syndrome of Inappropriate Antidiuretic Hormone Secretion. Normally, your body releases just enough antidiuretic hormone (ADH) to keep fluids balanced. SSRIs overstimulate this system. Your kidneys hold onto too much water, diluting the sodium in your blood. It’s not about drinking too much water. It’s about your body holding onto water when it shouldn’t.

This isn’t rare. About 6 out of every 100 older adults taking SSRIs develop hyponatremia. For some, it’s mild. For others, it’s dangerous. The risk spikes in the first two to four weeks after starting the drug or increasing the dose. That’s when you need to be most alert.

Who’s Most at Risk?

Not everyone on SSRIs gets hyponatremia. But certain people are far more vulnerable:

• Women-especially those who are thin or have a BMI under 25
• People already with low sodium levels (below 140 mmol/L)
• Those taking thiazide diuretics (like hydrochlorothiazide) for high blood pressure
• People over 75, especially with kidney changes or reduced body water

The combination of SSRIs and thiazide diuretics is particularly dangerous. Studies show this mix increases hyponatremia risk by over 20%. Many older adults take both-SSRIs for mood, diuretics for blood pressure. Doctors often don’t realize how dangerous this combo can be.

Some SSRIs carry higher risks than others. Fluoxetine (Prozac) has the highest association with hyponatremia among SSRIs. Venlafaxine (Effexor), an SNRI, is even riskier. If you’re starting an antidepressant and have risk factors, ask your doctor about safer options.

How Hyponatremia Leads to Falls

Falls aren’t just about slippery floors or poor lighting. In older adults, they often start inside the body.

Hyponatremia causes subtle but dangerous symptoms: mild confusion, feeling lightheaded, unsteady walking, sudden fatigue. These aren’t always obvious. A person might say, “I just feel off today,” or “I don’t feel like walking far.” These are red flags.

A 2023 study at Johns Hopkins found that older adults with even mild hyponatremia were 3 times more likely to have a fall in the next 30 days. Many of these falls led to fractures, hospital stays, or long-term disability. The connection isn’t always measured directly-but the pattern is undeniable.

And here’s the worst part: hyponatremia can be silent. Up to 40% of people with low sodium have no symptoms at all. That’s why checking blood levels isn’t optional-it’s essential.

What Doctors Should Do Before and After Prescribing SSRIs

There’s a clear protocol for safer SSRI use in older adults:

1. Check sodium before starting. A simple blood test should be done before the first pill is taken.
2. Test again at 2 weeks. This is the critical window. Most cases develop here.
3. Review all medications. Look for thiazide diuretics, NSAIDs, or other drugs that raise risk.
4. Choose safer alternatives when possible. Mirtazapine (Remeron) and bupropion (Wellbutrin) have much lower hyponatremia risk. They’re not perfect for everyone, but they’re safer for high-risk patients.
5. Teach patients what to watch for. Dizziness, confusion, weakness, or feeling unsteady? Call your doctor. Don’t wait.

The American Geriatrics Society’s 2023 Beers Criteria lists SSRIs as potentially inappropriate for older adults with existing hyponatremia or risk factors. That’s not a suggestion-it’s a warning.

The Monitoring Paradox

Here’s where things get confusing. Some experts say routine sodium testing saves lives. Others say it doesn’t reduce hospitalizations. A 2023 study in the Journal of the American Geriatrics Society found that even when doctors checked sodium levels, patients still ended up hospitalized for hyponatremia.

Why? Because checking alone isn’t enough. You need a plan. If the sodium is low, what happens next? Does the SSRI get stopped? Is the patient referred? Are fluids restricted? Are alternatives offered?

In many clinics, testing happens-but action doesn’t. A survey of 45 geriatricians found that 68% had official monitoring protocols, but only 32% followed them consistently. Staff shortages, lack of reminders, and unclear guidelines all play a role.

The solution isn’t just more tests. It’s better systems. Hospitals that used automated alerts in their electronic records-flagging SSRI + thiazide combinations and prompting sodium tests-saw an 18.7% drop in risky prescriptions. That’s real progress.

What You Can Do as a Patient or Caregiver

You don’t have to wait for your doctor to act. Be proactive:

• Ask: “Is this the safest antidepressant for me, given my other meds and health?”
• Request a sodium test before starting the SSRI and again at 2 weeks.
• Keep a list of all your medications-including over-the-counter pills and supplements-and bring it to every appointment.
• If you feel dizzy, confused, or unsteady after starting the medication, call your doctor. Don’t assume it’s just aging.
• Ask about alternatives like mirtazapine or therapy. Many older adults respond well to talk therapy or behavioral interventions.

If you’re a caregiver, watch for subtle changes. Has your loved one stopped walking to the mailbox? Are they eating less? Do they seem more confused than usual? These aren’t just “getting older”-they could be signs of low sodium.

What Are the Safer Alternatives?

If SSRIs are too risky, what else works?

• Mirtazapine (Remeron): This antidepressant has almost no link to hyponatremia. It can cause drowsiness and weight gain, but for many older adults, the trade-off is worth it.
• Bupropion (Wellbutrin): Doesn’t affect serotonin much, so hyponatremia risk is very low. Good for people who need energy, but not ideal for those with anxiety or seizure history.
• Psychotherapy: Cognitive behavioral therapy (CBT) is just as effective as SSRIs for mild to moderate depression in older adults. It has zero side effects. The problem? Access. Many don’t have transportation, insurance, or local providers.
• Exercise programs: Regular walking or tai chi improves mood, reduces fall risk, and can ease depression symptoms.

The key is matching the treatment to the person-not just picking the first drug on the list.

What’s Changing in 2025?

New tools are emerging. In 2024, the Geriatric Antidepressant Safety Collaborative launched AI-driven risk predictors that combine medication history, sodium levels, and fall risk scores. These tools help doctors spot high-risk patients before they’re harmed.

The FDA now requires stronger warnings on SSRI packaging. Medicare is starting to track hyponatremia-related hospitalizations as a quality metric. And a $2.8 million NIH study, launched in September 2024, is finally trying to answer the big question: What monitoring strategy actually saves lives?

Until then, the best defense is awareness, testing, and choosing wisely.

Final Takeaway

SSRIs aren’t bad drugs. But for older adults, they come with serious, preventable risks. Hyponatremia doesn’t come with a siren. It creeps in quietly-through dizziness, confusion, and weakness. And those symptoms? They’re the same ones that lead to falls, fractures, and hospital stays.

The fix isn’t complicated: test sodium before and two weeks after starting an SSRI. Review all medications. Choose safer alternatives when possible. Educate patients and caregivers.

Too many older adults are being prescribed SSRIs without a safety net. It doesn’t have to be this way. With a few simple steps, we can protect lives-and keep people walking safely, longer.