Your Chemo Drugs Are Making Heat Dangerous — Here's What to Do

Some chemo drugs block sweating, thirst, and heat perception. Here's what every cancer patient needs to know. #Chemotherapy #ChemoSideEffects #ElevatingCancerTreatment

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Episode Description:

Most heat safety advice assumes a healthy body.

If you're on cancer treatment, some of the drugs in your regimen may be working against you before you even step outside.

A few things Jay covers in this new video:

• The common antiemetic that makes your body passively take on the temperature of its surrounding environment
• Why you can be severely dehydrated and feel no urge to drink — and which drugs cause that
• The moment when multiple medications stop adding risk and start multiplying it
• Exactly what to ask your oncology team before the next heat advisory

This one could matter a lot this summer.

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Inquiries: 

info@elevatingcancertreatment.com

https://elevatingcancertreatment.com

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Disclaimer:
The information provided in this podcast is for educational and informational purposes only, and does not constitute medical advice. It is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have heard or read in this podcast or on this channel.
Reliance on any information provided by Dr. Jay Chaplin or Elevating Cancer Treatment is solely at your own risk. Dr. Jay Chaplin is a scientist and drug developer, not a medical doctor providing patient care. The content presented here reflects general scientific understanding and research, and may not be applicable to your individual health circumstances. Individual medical conditions and treatments vary, and no two situations are exactly alike.
Always consult with your personal healthcare provider before making any decisions about your health or treatment plan.

Transcript

SPEAKER_00 0:00

It's been a hot day here in Connecticut, and everywhere I went I was hearing drink plenty of water and stay in the shade. That's the heat safety advice you'll see everywhere this summer. And if you're on cancer treatment, I want you to hear this very clearly. That advice is not enough for you. I've reviewed hundreds of treatment plans, I read mutation reports, pharmacology sheets, medication interaction profiles, and every summer, without fail, I see the same dangerous gap. Patients on chemotherapy and support drugs, antiometics, anti-anxiety meds, just going about their lives in the heat, following the same general advice as everyone else. But if you're using any of those drugs, you're not everyone else. Some of the drugs that you might be taking right now are actively working against your body's ability to regulate its own temperature. If that sounds a little alarming, good, because it should prompt a conversation with your oncology team before the next heat advisory rolls out. And by the end of this video, you'll know exactly what to bring to that conversation and exactly what drugs are of most concern. Hello and welcome to Elevating Cancer Treatment, where we explain the science and debunk myths to help you navigate your health journey. My background is a little different. Beyond educating about cancer, I'm actually designing new drugs that are defining the future of oncology. This direct hands-on experience offers me a very different perspective of how these cancer treatments work on the body, interact with the cancer cells, and cause side effects. And these are insights that I'm excited to share with you. If that sounds interesting, make sure to like this video, subscribe to the channel, and hit that notification bell so you never miss an update. And please share it if you find it useful. I'm Dr. Jay Chaplin. An important reminder, I'm a PhD, not an MD. The information in this video is education and it's not medical advice. Every cancer is unique and no general information applies to everyone. Please remember that. Always consult with your healthcare provider for guidance on your specific situation. And two quick things. First, as a thank you for being here, I've created a free resource, 10 things to elevate your chemo journey, which you can download from the link below. And second, by signing up, you'll also get updates on that innovative cancer treatment I'm working on. I'm confident it represents a significant advancement in immunotherapy. So please take a moment, download your free guide, and join us in shaping the future of cancer treatment. This video is for you if you or someone you love is currently in cancer treatment or recovering from it, still dealing with some of the side effects. If you're taking any supportive care medications, anti-nausea drugs, anti-anxiety medications, sleep aids, or antipsychotics for treatment-related symptoms. Or if you've never had anyone sit down with you and explain what heat actually does to people who are on these medications. If you fall into any of those categories, stay with me. This is really important. So, again, I'm a cancer drug designer. I don't just explain these mechanisms, I study how drugs interact with biological systems at the molecular level. When I look at the class of medications and heat stress, I'm not just reading a brochure. I'm looking at receptor pharmacology, thermoregulatory mechanisms and pathways, and real clinical data. What I'm about to walk you through is grounded in that, plus guidance from the CDC's clinical heat and medication framework for clinicians. So your oncologist should know this. Now I'll also tell you about one specific scenario where the danger compounds so fast that it becomes a medical emergency like that. We'll get to it. But first, let's understand some of the basic mechanisms, because once you understand what's going on, everything else will make sense. So here's the biology. This is how your body handles heat. Your body is remarkably good at managing heat when nothing interferes with it. That's the catch. So the basic system is really clear, really simple. When your core body temperature rises, your hypothalamus, the brain region that acts as your internal thermostat, sends signals to your sweat glands all throughout your body to produce sweat. And also to the blood vessels near your skin surface to dilate so heat can radiate outward. So you also feel thirsty. This whole process is designed to work together. You drink water, you seek shade, the system corrects as you sweat, as blood vessels dilate, and you shed heat. This is called thermoregulation, and it's elegant, automatic, and critically dependent on your nervous system functioning normally. Now, here's the problem. Several medications commonly used in cancer care directly interfere with this system. Some of them block sweating. Some alter the hypothalamus itself and how it senses heat. Some blunt your perception of thirst so you don't get thirsty, you'll get dehydrated. Some sedate you to the point where you simply don't notice that you're overheating. That's a serious problem. When these mechanisms are compromised, your body cannot cool itself efficiently, even when it desperately needs to. And this is not some minor inconvenience. In hot weather, that's a path to heat exhaustion or heat stroke. So let's walk together through the specific drugs I really want you to know about. So the first one is olanzepine, or zyprexa. Olanzepine is increasingly used in cancer care, not for psychiatric symptoms, but as a part of antiametic and appetite-boosting regimens. It's quite effective at controlling chemotherapy-induced nausea, but its thermoregulatory effects don't change based on why you're taking it. And even at the low dose, it still has quite an effect on thermoregulation. A lanzepine is an atypical antipsychotic and it hits multiple receptor systems simultaneously. And in the context of heat, it creates three separate problems all at the same time. First, it decreases sweating. Your sweat glands are partially controlled by muscarinic receptors, and a lanzepine blocks those signals. That makes it physically harder to produce sweat. Less sweat, less evaporative cooling. Second, it directly affects the hypothalamus, the brain's thermostat. Research has shown it can alter the set point and responsiveness of this region, impairing the cascade of events that ought to kick in when your core body temperature rises. You just don't feel the heat. Third, and this one surprises a lot of people, it impairs thirst perception. The drug disrupts the neural signaling that tells your body it's dehydrated. You can be significantly fluid-depleted and feel no particular urge to drink. Three simultaneous disruptions to the same cooling system. Now, on a 90-degree day with high humidity, that combination is outright dangerous. CDC's clinical guidance lists atypical antipsychotics, including olanzepine, as medications that cause both impaired sweating and impaired temperature regulation. So it's not a fringe finding. This is mainstream clinical guidance you ought to be aware of because it increases the danger to you in high heat situations. Next one is prochlorperizine, or compazine. Prochlorperazine is one of the most widely used antiametics in oncology. It's a phenothiazine, an older class of antipsychotics, repurposed for nausea control in chemotherapy settings. It causes what's called poikelothermia, a state where the body starts to passively take on the temperature of its surrounding environment rather than regulating its own internal temperature. This is a literal pharmacological effect. Basically, it makes you act like a lizard. Your temperature goes to the surrounding temperature. Prochlorperizine limits both sweating and the body's ability to adjust blood flow to dissipate the heat. In a cool room, it's not a crisis, your body temperature can go down a fair bit. But in a hot car, on a beach, on a humid afternoon, this is how people end up in the emergency room. The Cleveland Clinic's prescribing documentation flags this explicitly. It's in the label, it's in the clinical databases, and yet patients are routinely not told about it before they go out and go out for their summer, enjoy the sun, and overheat. So a third is promethesine. Promethazine is another antiametic widely used in cancer care. It's an antihistamine with strong anticholinergic properties, and those anticholinergic effects are precisely what make it dangerous in the heat. Here's the mechanism. Sweating is triggered by acetylcholine binding to muscarinic receptors on sweat glands. We mentioned that earlier with a lenzepine. Anticholinergic drugs block that signal. If you block that signal, you block the sweat, and if you block the sweat, you lose your primary cooling mechanism. But promethazine adds a second layer, a different one, photosensitivity. It makes your skin substantially more reactive to UV radiation. You can burn faster and much more severely, which further stresses your body's ability to manage your heat load. Not only do you have trouble with the heat, you have trouble with the sun. And like a lanzepine, it disrupts hypothalamic thermoregulation through its antihistamine effects. So that's three different ways. The NHS, the FDA, the prescribing label, and most clinical pharmacology databases all flag these risks. Sun avoidance and protective clothing are explicitly recommended for patients on promethazine. If your oncology team hasn't told you this, you know. There's metaclopromide or reglin. Metaclopromide is one of the go-to antiometics for delayed nausea, commonly used a few days after chemotherapy infusions. It works on dopamine receptors, which is also why it can cause movement-related side effects with long-term use. It's kind of like a Parkinson's drug. Those same dopamine receptor effects extend to the thermoregulatory system. Numerous research papers have documented that metaclopromide and related drugs interfere with central temperature regulation, specifically, again, the hypothalamic pathways, the ones that coordinate sweating and heat dissipation. It also contributes directly to dehydration, and if you're already dehydrated from treatment, dehydrated from nausea-related fluid loss, and then also taking a drug that impairs your body's ability to compensate for heat, all those factors stack on top of each other. Alright, we got another one. Lorazepam or Adavan. Larazepam is a benzodiazepine and it's used in cancer care for anticipatory nausea, anxiety, and procedural sedation, and sometimes for sleep. It's genuinely useful. It's useful in a lot of ways, and it's also genuinely relevant for heat safety. Lorazepam doesn't primarily block sweating the way anticholinergics do. It doesn't really affect the hypothalamus, but it does cause sedation and cognitive slowing. And those effects create their own different heat risk profile. Think about what heat stress requires of you. You've got to notice that you're getting too warm. You've got to register that you're actually thirsty. You've got to decide to move to a cooler location and get something to drink. You've got to respond to early warning signals like dizziness or a rapid pulse. These are all cognitive tasks. Mild sedation blunts all of those. Patients on Lorazepam may stay in a hot environment far longer than they should. Not because they're actively ignoring the danger, but because the drug has reduced the signal-to-noise ratio of the entire warning system. There's also a drug storage consideration here. Larazepam is really heat sensitive in and of itself. If you have a bottle of it left in a hot car or a bag, it can degrade, lose potency, and become toxic. So this matters practically. It's not just you with heat stress, it's the drug with heat stress. So the CDC clinical guidance explicitly lists benzodiazepines under sedation or cognitive impairment with increased risk from heat exposure. Now, all of these things are problems by themselves, but they're much worse when you mix them and they compound. And that's really what I want you to sit with for a moment. Cancer patients, like many of our subscribers, who are on active treatment, are frequently taking multiple medications from this list simultaneously. An antiemetic regimen might include olanzepine for immediate effect to regain your appetite. It might contain larzepam for sleep aid and stress relief. It might contain a corticosteroid. It might add prochlorperazine as a rescue antiemetic. Promethazine might be in the medicine cabinet for breakthrough nausea coming in later at home. It could be all of those. Each of them individually impairs thermoregulation through different mechanisms. But you put them together, the effect is not just additive. It's synergistic. They all multiply. All of those factors multiply. And the CDC guidance makes exactly this point. Combinations of these medications, especially when they hit different parts of the same system, significantly amplify heat risk in ways that aren't obvious when you're looking at any single drug. Each individual one may not be that big of a deal, but you take two or three or five, the risk is really, really big, and we don't talk about it often enough. So this is the scenario I want you to be alert to. Not one medication on a warm day, but multiple medications, stacked effects, high heat, and a body already under stress from treatment. So, awareness is good. What do you actually do? None of this means you should stop your medications. I want to be absolutely clear. Do not abruptly stop any of these drugs without a plan coordinated with your oncology team. Abrupt cessation creates its own risks. Don't do that. What it means is building a heat safety plan around your medication regimen. And here's what that sort of thing looks like. First, hydrate proactively, not reactively. Because several of these drugs impair thirst perception, you can't rely on thirst as your signal to drink. Create a schedule. Drink on a schedule. Get electrolyte fluids, not just water. Those help, especially if you're managing any treatment-related dehydration. 2. Limit your outdoor exposure during peak heat. On days with heat advisories, what the CDC calls heat risk, orange, red, or magenta days, the risk-benefit calculus shifts dramatically. This is especially true in the 24 to 48 hours following a chemotherapy infusion when antiometic drug levels in your system are the highest. Keep your environment generally cool. Not comfortable, cool. Air conditioning is an actual medical asset for someone on these medications. It's not a luxury. If you don't have access to AC, know where your nearest cooling center is, or go to some place like a mall or a theater that can keep you cool in the middle of the day. Know your warning signs and tell someone else. Because sedation and impaired perception can make you the last person to recognize you're in trouble. Identify a family member or a caregiver or a close friend who knows to watch for confusion, dizziness, rapid pulse, flushed or hot dry skin, especially if you stop sweating, even in the heat. Nausea can also be a sign, though that can be mistaken for a treatment side effect. And worst of all, fainting. And again, store your medications correctly. Don't leave pills in a hot car, a sunny windowsill, or an unventilated bag. Especially larazipam. Heat degrades it rapidly. So please, talk to your oncology team proactively. Ask them, given my current medication list, what specific heat precautions do I need? Are there any adjustments to timing or dosing on high heat days? There might be. Many, many drugs are cleared through the kidneys, and if you're dehydrated on a high heat day, it can reduce the clearance. Who do I call if I have symptoms? You should know these things. The CDC Guidance for Clinicians recommends that oncology teams build an entire medication-specific heat plan with every patient. If your team hasn't done that, ask them to. So I know you're watching this because you want to understand your treatment, not just accept it. And that's exactly the right posture when you're navigating cancer care. There's a lot of moving parts, and you really need to understand what you're doing to have control and agency with it. The patients I most want watching this channel are the ones who take what they learn and bring it back to their care team as informed, engaged participants. I hope that you're one of those patients. Heat stress with cancer medications is a preventable harm. You can prevent all of these issues. And you just armed yourself with the awareness to do that. If you want to understand how chemotherapy drugs interact with your basic physiology in ways that your oncologist may not have the time to fully explain, watch this next video right here. I break down what's actually happening at the cellular level during treatment and why that context matters for every decision you're making. If this video gave you something useful, please like it and subscribe. It genuinely helps the information reach more people who need to see it. Share it with someone going through treatment this summer. You might actually save a life. And please leave a comment. If you're currently taking any of these medications, did your care team ever talk to you about heat precautions? I'm slow to the game, but I do eventually read all the comments. Eventually. And I'd love to know, and I'm sure we'd all love to see some indication of how oncologists are treating these serious issues. Thank you. Beyond these videos, if you need more personalized guidance or a deeper dive into specific treatments to have your treatment be as effective as possible, I offer one-on-one sessions and medical advocacy. You can find information on our website, which is linked down below. Again, if you found this video informative, please give it a thumbs up, click the notification bell, and subscribe to our channel for more science based cancer insights.