Heart Inflammation Risks from First-Generation Antihistamines

Hello, I would like to inquire about heart inflammation caused by first-generation antihistamines?

The doctor did not understand my medical history and mistakenly prescribed me 30 mg of the antihistamine diphenhydramine, which I took in combination with my sedative (I had taken half a sedative in the morning).
The combination of sedatives resulted in...
poison.
This interaction caused me to lose consciousness, my heart rate spiked to 180 bpm, and my blood pressure soared to 170.
I was continuously vomiting.
This is a known cardiac toxicity associated with first-generation antihistamines.
After that incident, I experienced constant shortness of breath, was unable to walk, felt weak, and my blood pressure remained elevated at around 160, which was completely different from my previous health status.
This indicates that some part of my body is inflamed.

I would like to know how a doctor can detect inflammation in my heart.
I consider myself lucky to be alive, but I am still experiencing persistent shortness of breath and cannot go outside; I faint as soon as I step out.
Am I suffering from myocarditis or coronary artery obstruction? The cardiac toxicity of the medication can lead to muscle toxicity, suppress heart muscle function, cause coronary artery spasms, damage endothelial cells, and result in thrombotic occlusion leading to myocardial ischemia.
Note: In May 2020, the "Benadryl Challenge" went viral on TikTok, encouraging teenagers to take more than a dozen antihistamine pills and post videos of their hallucinatory experiences.
This led to at least three hospitalizations in Fort Worth, Texas.
One teenager experienced hallucinations and incoherent speech after taking 14 pills, with a resting heart rate of 199 bpm.
On August 30, 2020, local media in Oklahoma City reported that a 15-year-old girl died from an overdose while participating in this challenge.
This prompted the FDA and Benadryl's manufacturer, Johnson & Johnson, to issue warnings about drug misuse, stating, "Overdosing on Benadryl can lead to serious heart problems, seizures, coma, or even death." Jessica Nouhavandi, Chief Pharmacist and Co-Founder of Honeybee Health, stated, "The maximum daily dose of Benadryl is 300 mg, with each tablet typically containing 25 mg.
Overdose can lead to side effects including drowsiness, dry mouth, constipation, and urinary retention, and in severe cases, may cause hallucinations, psychosis, seizures, or coma." Diphenhydramine is a first-generation antihistamine primarily used to treat allergies, but it can also be used for insomnia, cold symptoms, Parkinson's tremors, nausea, motion sickness, and extrapyramidal symptoms, and it has local anesthetic properties.
Diphenhydramine has sedative effects and is sometimes used as a sleep aid or anxiolytic.
It can be administered orally, intravenously, or intramuscularly.
The maximum effect usually occurs about two hours after administration and can last up to seven hours.

WEWE, 40~49 year old female. Ask Date: 2022/11/08

Dr. Wu Xueming reply Cardiology

Based on your description, it is not possible to diagnose whether it is myocarditis.
Please go to the hospital for further examination.

Reply Date: 2022/11/08

More Info

The concerns you've raised regarding the use of first-generation antihistamines, particularly diphenhydramine (Benadryl), and their potential impact on heart health are indeed significant. Your experience with the medication, especially in conjunction with a sedative, highlights the risks associated with polypharmacy and the need for careful monitoring of drug interactions.

First-generation antihistamines like diphenhydramine are known for their sedative properties, which can lead to increased drowsiness and other central nervous system effects. However, they also have anticholinergic effects, which can impact the cardiovascular system. In some cases, these medications can cause tachycardia (rapid heart rate), hypotension (low blood pressure), or hypertension (high blood pressure), particularly when taken in higher doses or combined with other sedatives. Your reported symptoms of a heart rate of 180 beats per minute and a blood pressure spike to 170 mmHg are concerning and suggest a potential adverse reaction to the combination of medications.

In terms of diagnosing heart inflammation, or myocarditis, it typically involves a combination of clinical evaluation, laboratory tests, and imaging studies. A healthcare provider would likely start with a thorough history and physical examination, followed by blood tests to check for markers of inflammation (such as C-reactive protein or troponin levels) and possibly viral serologies if a viral cause is suspected. An electrocardiogram (ECG) can help assess heart rhythm and detect any abnormalities. In some cases, an echocardiogram or cardiac MRI may be necessary to visualize the heart's structure and function.

Given your symptoms of persistent shortness of breath, weakness, and the inability to walk without feeling faint, it is crucial to seek immediate medical attention. These could be signs of serious conditions such as myocarditis or coronary artery disease, especially considering your history of medication use and the acute reaction you experienced.
It is also important to note that the misuse of diphenhydramine, as highlighted by the "Benadryl Challenge" on social media, has raised awareness about the dangers of overdosing on this medication. The FDA has issued warnings regarding the potential for serious side effects, including severe cardiovascular events, seizures, and even death, particularly in cases of overdose.

In summary, your situation underscores the importance of clear communication with healthcare providers regarding your medical history and current medications. It is essential to have a healthcare professional evaluate your symptoms and perform the necessary diagnostic tests to determine the underlying cause of your heart issues. Avoiding self-medication and ensuring that all healthcare providers are aware of your complete medication list can help prevent similar incidents in the future. Please prioritize your health and seek medical attention as soon as possible.

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