Clarithromycin Drug Interaction Checker
Enter your current medications to check for dangerous interactions with clarithromycin. This tool identifies high-risk combinations that can cause severe health complications.
Clarithromycin is an antibiotic that works well against certain bacterial infections - pneumonia, bronchitis, skin infections. But here’s the catch: it’s one of the most dangerous antibiotics you can take if you’re on other meds. Not because it’s weak, but because it’s too powerful at messing with how your body processes drugs. And that can kill you.
Why Clarithromycin Is a Hidden Killer
Clarithromycin doesn’t just kill bacteria. It also shuts down a key enzyme in your liver called CYP3A4. This enzyme is responsible for breaking down about half of all prescription drugs. When clarithromycin blocks it, those drugs build up in your blood like a clogged drain. Toxic levels. No warning. No symptoms at first. Then - organ failure, heart rhythm crashes, muscle breakdown, death. This isn’t theoretical. In 2020, the FDA recorded 58 serious or fatal cases where clarithromycin was taken with colchicine. That’s just the reported ones. Real numbers are likely much higher. One study showed that when clarithromycin was given with colchicine, colchicine levels jumped by 282%. That’s not a small bump. That’s a red alert.The Deadliest Combo: Clarithromycin and Colchicine
Colchicine is used for gout and some rare inflammatory conditions. It’s safe - until you add clarithromycin. Patients on daily colchicine for years can be fine. Then they get a sinus infection. Prescribed clarithromycin. Five days later, they’re in the ER with violent vomiting, diarrhea, muscle weakness. Within two weeks, they’re dead. A 76-year-old woman with chronic gout took her usual colchicine dose. Her doctor gave her clarithromycin for a cough. Eleven days later, she died from multi-organ failure. Her case was one of 12 documented in a single study. All had the same pattern: no prior issues. No overdose. Just the combo. The Institute for Safe Medication Practices calls this a Category A high-alert interaction - the highest risk tier. That means even trained professionals can miss it. Pharmacists have stopped prescriptions on the spot. One case in 2022: a 72-year-old on both colchicine and rivaroxaban (a blood thinner) was about to get clarithromycin. The pharmacist caught it. Saved the patient’s life.Statins Are Also a Death Trap
Simvastatin, lovastatin, and even atorvastatin are commonly prescribed to lower cholesterol. They’re broken down by CYP3A4. Add clarithromycin, and statin levels skyrocket. Result? Rhabdomyolysis - a condition where muscle tissue breaks down and floods your kidneys with toxic proteins. A 68-year-old man took 40mg of simvastatin daily for years. Got clarithromycin for a chest infection. Three days later, he couldn’t walk. His muscles were burning. His urine turned dark. He was admitted to the ICU. Required dialysis. Survived - but barely. His doctor didn’t know the interaction existed. Neither did the pharmacist. The Mayo Clinic lists 38 drugs that shouldn’t be mixed with clarithromycin. Statins are #1 and #2 on that list. Azithromycin, another macrolide antibiotic, doesn’t do this. It’s why doctors now prefer azithromycin for most infections - fewer interactions, same effectiveness.
Heart Risks: QT Prolongation and Torsades de Pointes
Clarithromycin can also mess with your heart’s electrical rhythm. It prolongs the QT interval - the time between heartbeats. When combined with other QT-prolonging drugs (like certain antiarrhythmics, antidepressants, or even some antifungals), it can trigger a deadly heart rhythm called torsades de pointes. The American Heart Association says clarithromycin increases this risk by 2.7 times compared to antibiotics that don’t affect the heart. The FDA added a boxed warning in 2023: “Concomitant use has resulted in fatal and near-fatal colchicine toxicity.” That’s the strongest warning they give. Only life-threatening risks get this label. Patients with existing heart conditions, kidney problems, or those over 65 are at highest risk. One study found 42% of seniors on clarithromycin were also taking a dangerous combo drug. That’s more than 4 in 10. And most didn’t know.Other Dangerous Combinations
Clarithromycin doesn’t stop at colchicine and statins. It also dangerously interacts with:- Calcium channel blockers - verapamil, diltiazem, amlodipine. Can cause dangerously low blood pressure or heart failure.
- Digoxin - used for heart rhythm. Levels can spike, causing nausea, confusion, fatal arrhythmias.
- Warfarin - blood thinner. Clarithromycin can make it stronger, leading to uncontrolled bleeding.
- Ergotamine - used for migraines. Can cause severe limb ischemia, gangrene.
- Theophylline - for asthma. Can cause seizures, heart attacks.
- Immunosuppressants - cyclosporine, tacrolimus. Risk of kidney failure.
Why Azithromycin Is the Better Choice
Azithromycin is in the same antibiotic family as clarithromycin. Same class. Same purpose. But here’s the difference: azithromycin barely touches CYP3A4. It doesn’t cause these deadly interactions. A 2018 study found clarithromycin was 2.8 times more likely to cause serious drug interactions than azithromycin. Since then, prescriptions for clarithromycin have dropped 28% in the U.S. Azithromycin now makes up 63% of all macrolide prescriptions. Why? Doctors switched because they didn’t want to kill their patients. The American College of Physicians now recommends azithromycin as the first-choice macrolide for anyone taking three or more medications. That’s not a suggestion. It’s a guideline. Because the cost of a mistake isn’t just a side effect. It’s death.
What You Should Do
If your doctor prescribes clarithromycin, ask these questions:- “Am I taking anything that could interact with this?”
- “Is there a safer antibiotic I could take instead - like azithromycin?”
- “Could this interact with my cholesterol medicine, gout pill, blood pressure drug, or heart medication?”
What If You’ve Already Taken Them Together?
If you’ve taken clarithromycin with colchicine, simvastatin, or any other high-risk drug:- Stop clarithromycin immediately.
- Call your doctor or go to the ER.
- Watch for: unexplained muscle pain or weakness, dark urine, severe diarrhea or vomiting, dizziness, irregular heartbeat, fainting.
The Bigger Picture
Clarithromycin isn’t going away. It’s still used for serious infections like Mycobacterium avium complex, especially in people with HIV. But for common infections - sinusitis, strep throat, bronchitis - it’s rarely necessary anymore. The FDA, CDC, and top medical societies agree: the risks outweigh the benefits for most patients. Especially seniors. Especially those on multiple meds. We’ve seen this before. Erythromycin, another macrolide, was once widely used. Then the interactions became clear. Prescriptions collapsed. Azithromycin replaced it. Clarithromycin is next. The writing’s on the wall. The real question isn’t whether clarithromycin works. It’s whether it’s worth the risk. For most people - no. There’s a safer option. Use it.Can I take clarithromycin if I’m on a statin?
No. Combining clarithromycin with simvastatin or lovastatin can cause severe muscle damage (rhabdomyolysis), kidney failure, or death. Atorvastatin is also risky. If you need an antibiotic and take a statin, ask for azithromycin instead. It’s just as effective and doesn’t interact.
Is clarithromycin safe for elderly patients?
It’s generally not safe. Nearly half of seniors on clarithromycin are also taking a dangerous interacting drug. The American Geriatrics Society specifically advises avoiding clarithromycin in patients 65 and older who take CYP3A4-metabolized drugs like colchicine or calcium channel blockers. Azithromycin is the preferred alternative.
How long does the interaction last after stopping clarithromycin?
Clarithromycin’s effect on CYP3A4 can last up to 10 days after the last dose. Even after you finish the antibiotic, your body is still processing other drugs slower than normal. Don’t restart statins, colchicine, or other high-risk meds until your doctor says it’s safe - usually after a 10-day waiting period.
What should I do if my doctor prescribes clarithromycin?
Ask: “Is there a safer alternative?” and “Am I taking anything that could interact with this?” Bring a list of all your medications - including supplements and OTC drugs. If your doctor says clarithromycin is necessary, ask them to check the interaction risk with a pharmacist before you fill the prescription.
Are there any foods or drinks I should avoid with clarithromycin?
Unlike some antibiotics, clarithromycin doesn’t interact with food or alcohol. But the extended-release version must be taken with food to be absorbed properly. The real danger isn’t what you eat - it’s what else you’re taking. Focus on your other medications, not your diet.
Comments
shawn monroe
November 28, 2025 AT 01:44 AMClarithromycin is a CYP3A4 inhibitor-period. It’s not just a ‘risk,’ it’s a pharmacokinetic landmine. When you combine it with colchicine, you’re essentially disabling the liver’s primary detox pathway for a drug with a narrow therapeutic index. The 282% spike in colchicine AUC? That’s not a typo. That’s a death sentence waiting for a prescription refill. And statins? Simvastatin + clarithromycin = rhabdomyolysis on a timer. I’ve seen ICU beds taken by this combo. Azithromycin isn’t just ‘safer’-it’s the only ethical choice in primary care now. Stop normalizing this. Stop. Stop.
marie HUREL
November 28, 2025 AT 17:36 PMI’m a nurse, and I’ve had to pull a clarithromycin script twice this year. Both times, the patients were on statins. One was 73, on simvastatin for 12 years. She didn’t even know what CYP3A4 was. Neither did her PCP. We switched her to azithromycin and she’s fine now. I wish more doctors just asked, ‘Is this really necessary?’ instead of just checking the box. It’s not about being cautious-it’s about not killing people by accident.
Lauren Zableckis
November 29, 2025 AT 08:43 AMThis is why I always bring a printed list of my meds to every appointment. My pharmacist flagged this exact interaction last winter. I was prescribed clarithromycin for bronchitis and was on amlodipine. She stopped it cold. Said if she didn’t, she’d be liable. I didn’t even know drugs could do that to each other. Now I ask every time. It’s scary how little doctors know.
Asha Jijen
November 30, 2025 AT 01:59 AMbro clarithromycin is just a trap lol they want you dead or something. statins + this = muscle soup. i got my grandma on colchicine and she almost died. doctor said its fine. pharmacist said no. she lived. dont trust doctors. trust pharmacists. always.
Edward Batchelder
November 30, 2025 AT 10:42 AMThis is exactly the kind of public health education we need more of. I’m from a rural community where antibiotics are prescribed like candy. I’ve seen patients die from interactions because no one-no one-asked about their other meds. Azithromycin is not just an alternative-it’s the new standard. We must advocate for it. We must demand it. We must teach our elders to ask: ‘Is there a safer option?’ Because sometimes, the safest option is the one that doesn’t exist in the doctor’s mind.