This article originally appeared on Inside Climate News, a nonprofit, independent news organization that covers climate, energy and the environment. It is republished with permission. Sign up for their newsletter here.
Normally, Shelbey Ward uses her platform AdAstraStickers on TikTok to promote the clever, nerdy stickers she makes and sells, with occasional commentary on life thrown in for good measure. But in May she decided to use her platform to share a PSA about heat and psychiatric meds.
Ward had seen other content creators posting about heat intolerance with common medications generally considered first line treatments for anxiety and depression—selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs). But she felt the need to post her own warning as none of the videos she had seen covered the full spectrum of psych meds that impact heat tolerance.
Going into the summer, many mental health advocates began sharing warnings about the dangers of overheating while taking SSRIs and SNRIs. But Ward said, “It’s not just SSRIs and SNRIs. It’s any medication that affects the hypothalamus.”
In her post, Ward went on to list that this includes tricyclics, benzodiazepines, antipsychotics and some blood pressure medication that is often prescribed off label for anxiety. And, she added, stimulants also raise your risk of heat stroke by increasing core body temperature.
Ward had thoroughly researched the subject after she had overheated on an SSRI and missed only a few medications in her list of heat-risk elevating psych meds, which was impressively thorough for a 40-second video.
However, Dr. Pope Moseley, a biomedical sciences researcher and intensive care physician at Arizona State University who has been researching the links between heat death and psychiatric illness for years, said that to actually understand the risks, you have to “make sure that we have a base understanding … of heat-related illness.”
Many psych meds “tend to interfere with the thermostat of the body,” said Moseley, referring to the hypothalamus. It’s what tells you to start sweating and to shunt blood flow to your extremities to facilitate cooling. But when it’s too hot, air flow can’t cool you down, so you start to sweat. “Then it’s totally evaporative cooling… that’s what your body is,” said Moseley. “It’s a big evaporative cooler.”
All of that is controlled by the hypothalamus. A number of neurotransmitters control the hypothalamus; serotonin is one of them. “If you bathe the thermostat in serotonin, which is essentially what SSRIs are doing, then it becomes less sensitive to temperature changes, so it doesn’t react as quickly, so it might not tell your body to shunt more blood or to sweat.”
Paradoxically, SSRIs and SNRIs can also confuse the body’s thermostat and cause hot flashes and unnecessary sweating, he said. You can sweat so profusely that it can cause dehydration and electrolyte imbalance. This is exacerbated when it’s hot.
“The fundamental problem is that we have about five liters of blood circulating in our bodies and we have about 15 liters of tubing. So our bodies constantly make choices where it’s sending blood,” said Moseley. “It’s really an important thing to be able to choose where to send blood. You don’t want to be full up all the time, because then you couldn’t temperature regulate in the heat. However, that’s a problem, because when you’re sending a huge amount of your heart output to your skin, some organs lose their share.”
This is even worse when you are dehydrated and have less blood volume to work with in the first place.
The Mechanics of Heat Stroke
Heat stroke, at its core, is not just an intensification of heat exhaustion, Moseley said. After a certain threshold, so much blood is directed away from the internal organs that they begin to shut down. This is when heat exhaustion becomes heat stroke. A common side effect of this organ damage is that the gut becomes damaged to the point where it starts to leak.
The holes aren’t large enough for bacteria to fit through, said Moseley, “but components of bacteria called endotoxin, the shell of the bacteria, start coming through. And when that endotoxin hits your liver, you get what we call a cytokine storm.”
A cytokine storm is what happens when the immune system goes berserk. It starts indiscriminately attacking the body and causes an extremely high fever. If this sounds familiar, said Moseley, that’s because “we used to talk about it with Covid.”
Understanding the mechanics of heat stroke is essential to knowing why some medications may increase the risk of heat stroke beyond raising the susceptibility to heat.
For example, many medications, including common ones for depression and ADHD, like SSRIs and stimulants, have been linked to leaky gut syndrome. If the gut barrier is already compromised, it greatly lowers the threshold for endotoxins to start escaping the gut.
“When we talk about heat related illness, we’re talking about seven to 10 percent of the impact of heat,” said Moseley. “Heat is the force multiplier of disease.”
Stimulants are particularly risky. On top of increasing the risk of leaky gut, they also tend to increase core body temperature. “So the stimulant causes micro fasciculation of muscle, so you actually generate heat,” said Moseley. These micro fasciculations—tiny, involuntary muscle contractions—are why ADHD meds may often make people feel “twitchy” or “jumpy” even though they are better able to focus.
The good news is most people can take a couple days, or even a week break from taking their stimulants with little to no risk to their health. Though they may find themselves unable to focus, unusually hyper, more impulsive and generally unproductive, these symptoms should only last until they resume their stimulants. This is not the case with most medications, and for some people, the benefits of increased heat tolerance will not outweigh the risks of lost productivity and lack of impulse control.
With the exception of stimulants, people can’t just stop their psychiatric medications when it’s hot out. Dr. Robin Cooper, the co-founder and president of the Climate Psychiatry Alliance and a practicing therapist in San Francisco, said that will just make symptoms reassert themselves, causing more problems, and in some cases (like with SSRIs and SNRIs,) medications must be carefully tapered or risk debilitating withdrawal symptoms from stopping the medications too abruptly.
Schizophrenia and Heat
The risks are even higher for people with schizophrenia. Schizophrenia itself seems to deregulate how the body perceives heat. “Before antipsychotics were available for treating schizophrenics, there still was increased death rates and trauma among schizophrenics experiencing heat. Therefore, that indicates to us that this is more than just a medication impact,” said Cooper.
“If you ever have seen during an extreme heatwave, some guy with layers and layers and jackets on, he most likely has schizophrenia. He won’t feel hot, he might even feel cold,” said Cooper. “Intrinsic to the disease of schizophrenia is this inability to experience the body’s heat, but there is also a component of psychotic illness which can impair one’s ability to assess risk, and effectively put in plans for protecting oneself.”
Data from a 2021 British Columbia extreme heat event, which lasted for about three weeks, offers some insight into just how much severe mental illness raises the risks of heat. “The severely mentally ill die at a much greater rate than those without severe mental illness diagnoses,” Cooper said.“Three times the rate, based on the mortality rates in British Columbia during an extreme heatwave. Severe mental illness was the top underlying medical condition that had contributed to mortality during that heatwave. And depression was either 10 or 11 on that list,” she said.
Based on a study done by the British Columbia Center for Disease Control and Prevention, looking specifically at the schizophrenia population in British Columbia, people with schizophrenia accounted for eight percent of all deaths during the hottest part of the heat dome. Only one percent of the population of British Columbia have schizophrenia.
The disparity was even more pronounced among those taking antipsychotics. Among those who died, 80 percent had filled a prescription for antipsychotics in the three months before the heat dome, compared with 55 percent of schizophrenics who survived.
Though antipsychotics can help relieve symptoms of psychosis, they do not help with the impaired temperature perception. In fact, said Cooper, “antipsychotics can interfere with the body’s ability to maintain heat regulation, and make it harder to cool down, making it more difficult to maintain a stable core body temperature.”
Planning for Heat
The key to staying safe during a heat wave, said Cooper, is to know your risks ahead of time. “Everyone should be talking to their doctor about the heat risks associated with their medications, and not just psychiatric medications,” she said. “In some cases there are other treatment options available with lower associated heat risk, or else your doctor can help you create a plan for what you need to stay safe during a heat event.”
Hayley Blackburn, a pharmacologist and professor at the University of Montana, believes knowing your risk factors is the minimum in medication preparedness in a climate changed world. Part of the problem, said Blackburn “is that these risks are seasonal. Nobody who’s picking up their SSRI for the first time in January is even thinking about the hot months ahead and the heat risks.”
Blackburn is co-founder of Rx for Climate, an independent virtual community focused on supporting sustainable and climate adapted pharmacy practices and facilitating connections between environmentally engaged pharmacy practitioners.
Aside from the direct hazards of heat, on certain medications, he said, dehydration dramatically raises the risk of kidney damage. “For example, in the case of lithium, if you have somebody who becomes dehydrated, you can end up with increasing levels of lithium and increased toxicity of lithium as a result. It is one of those drugs that has to be in kind of a narrow range for efficacy, while also remaining at safe levels for people,” said Blackburn.
Long-term lithium use, while incredibly effective for treating bipolar disorder, also doubles the risk of kidney failure. A single episode of severe dehydration can be enough to cause permanent kidney damage in someone taking lithium.
“As long as you are talking with a doctor or a pharmacist about your specific medication and the associated risks,” said Blackburn, “and being really proactive in doing some sort of emergency planning, you should be OK.
Stockpiling Medications
Ward, the TikTok influencer, wishes she had known to ask about heat interactions when she first started on her mood stabilizer and SSRI six years ago. Until six months ago, she had no idea that her medication could be causing her to overheat and burst out sweating from something as simple as vacuuming the house.
“High heat events are really difficult for me. Sometimes I have to wear more layers, just so that it absorbs the sweat, but then I overheat more easily,” she said. “So it’s kind of a double edged sword. And I drink more water, but then I’m going to the bathroom more often, so it gets really difficult to manage.”
Ward has dealt with heat waves by hunkering down with the air conditioning blasting. This has worked so far, but can get expensive. Now that she knows that her medications raise her risk of heatstroke, she is considering a backup plan in case the power goes out.
She at least knows that even if there is a disaster, she will have her meds. “We have go bags like the Red Cross recommends,” said Ward, who keeps an extra week’s worth of meds packed at all times.
According to Blackburn, the Red Cross recommended emergency supply likely wouldn’t be enough for a large-scale disaster. For essential medications, like blood pressure and antipsychotics, Blackburn recommends keeping an extra two week supply on hand as a “cushion” in case of a natural disaster or emergency affecting the supply chain.
Dr. Oliver Freudenreich, a psychiatrist who specializes in complex cases at Massachusetts General Hospital in Boston, thinks a two or three month supply is a safer bet, if you can stockpile that much. But, said Freudenreich, that is only for the most essential medications.
“What is actually an essential medicine? You know, some people are on 10 medicines. Do they really need to have for all 10 medicines an extra… three months supply? I’m not so sure.” Freudrenreich recommends going over your current prescriptions with your doctor or pharmacist to determine which medications you need to have in reserve.
“If you have medicines like cholesterol, for example, you’re really just managing the long term risk of, say, having, a heart attack or a stroke,” said Freudrenreich. Stopping those medications in the short term won’t increase your acute risk of stroke, though if you are off it for an extended period of time, you will raise your cardiovascular risk in the long term.
On the other hand, high blood pressure medication may be essential as high blood pressure acutely raises the risk of heart attack and stroke.
If you do decide to create a medication stockpile, it is important to use the medications you have stockpiled and save new ones frequently enough that you don’t let any of the emergency medications expire. If you are trying to create an emergency medication supply, Freudrenreich recommends speaking to your doctor. “We physicians are also humans, you know, and some of us will be more accommodating of these requests than others,” he said.
Creating a backup supply of medications is looking more necessary all the time. Hurricane Helene severely damaged a Baxter International plant in North Cove, North Carolina, which supplies over 60 percent of IV fluid nationwide. A month out, nearly all elective and non-emergency surgeries are still on hold as hospitals triage their IV fluid supply.
But the situation is not universally grim. Some hospitals and health systems implemented a strategic stockpile policy in the wake of the Covid-19 pandemic, giving them more flexibility as they figure out how to ration the fluid they have left.
The same concept applies to rationing medications for individuals. The more you have in reserve, the longer you can make it stretch.
Having to ration medication is unfortunately far more common than you might think, according to Blackburn. Much of Blackburn’s work is focused on making the healthcare system more resilient in the face of climate change.
This can often mean building in redundancies in case of supply chain shocks. “If people can’t get their medications for over two weeks, that’s really a failure of the healthcare system,” said Blackburn.
As pharmacists work to build climate resilience into the drug distribution system, she said, “that’s something that needs to be front of mind: how are we securing the supply chain? What are we doing to make sure that we can have surge capacity for patients who lose their meds in a flood? How do we plan for this?”
While Blackburn tackles the issue at a system level, Freudrenreich is more focused on the individual. “The problem with withdrawal is it’s very individual, and some people can just stop them with zero problems. On the other hand, there’s a group that it takes them months to wean off, very slowly to avoid the withdrawal,” said Freudrenreich.
But, if it becomes clear that it will take a long time to access more medications, and you are starting to run low, “I absolutely would start to think, well, what if I took half?” he said.
By rationing the medicine you have left you can stretch the time until you run out. How to best ration what you have left will be a very individual decision, often dependent on the starting dose.
“In most instances, taking half will probably still keep you in the therapeutic range,” said Freudrenreich, meaning the medication will still be effective, just not at full strength. “But if you’re already on a low dose already, and you take half, then you might only be getting a sub therapeutic dose.”
Either way, said Freudrenreich, it is better to figure these things out ahead of time with your doctor instead of muddling through on your own in a disaster.
