Written by: THE BALANCE
Medically reviewed by Dr. Sarah Boss, MD
Last updated: February 5, 2026
Fact checked
Quick Summary
  • Substance abuse refers to compulsive or excessive use of a compound that alters your biochemical or neurological state.
  • The issue is commonly associated with psychological or physiological dependence on the substance in question, which may lead to significant impairments in the ability to work in societal and occupational roles.
  • While substance abuse can potentially deteriorate all existing health complaints, it can often generate new issues for the user, particularly concerning heart health.

Substance abuse refers to compulsive or excessive use of a compound that alters your biochemical or neurological state. The issue is commonly associated with psychological or physiological dependence on the substance in question, which may lead to significant impairments in the ability to work in societal and occupational roles. While substance abuse can potentially deteriorate all existing health complaints, it can often generate new issues for the user, particularly concerning heart health.

This guide will help you identify the worst drugs for your heart and the side effects associated with each of them. (source: NHLBI, 2022 (MI))

Mentioned below are some of the worst drugs for your heart, along with the possible side effects they may trigger:

Nicotine

Research investigating nicotine use has discovered that this compound alone does not pose an overwhelming risk to heart health. Its non-combusted variety carries a minimal potential to affect the heart negatively. The combustible variety, on the other hand, is verifiably dangerous for the heart, as chronic smoking can lead to: (source: StatPearls, 2024 (Cocaine))

  • Thickening and narrowing of the blood vessels
  • Increased risk of blood clots
  • Decreased levels of good cholesterol
  • Increased fat levels in the blood
  • Increased plaque buildup

The abovementioned issues make the body a breeding ground for a heart attack.

Alcohol

Though more famous for its harmful effects on the liver, alcohol can also impact the heart and contribute to developing several cardiac issues. Research confirms the association between excessive alcohol use and the following three heart diseases:  (source: source)

  • Atrial fibrillation is characterised by a quivering or irregular heartbeat, making an individual vulnerable to heart failure and stroke
  • Congestive heart failure is characterised by an inability of the heart to pump blood to other body parts efficiently
  • Myocardial infarction or heart attack is characterised by a partial or complete blockage of the blood flow to the heart

Each disease mentioned above poses a severe health risk and must not be taken lightly.

If you or someone you know is a chronic drinker and suspects heart disease, look for the following signs of heart disease from alcohol:  [4]

  • Shortness of breath
  • Excessive fatigue
  • Swelling in feet, ankles, and legs
  • Weakness
  • Reduced appetite
  • trouble concentrating
  • Excessive dizziness
  • A rapid or irregular pulse

Cocaine

Touted as the worst drug for heart health, cocaine can be harmful to the cardiac muscles. As the body begins breaking it down, it undergoes an array of effects that may lead to one or more medical emergencies. The more cocaine someone uses, the higher their chance is for these emergencies to occur. The risk becomes exceptionally high if a user is already a heart patient or predisposed to cardiac problems. (source: CDC, 2024)

Some of the most common side effects of cocaine on the cardiovascular system include: 

  • Elevated heart rate
  • High blood pressure
  • Decreased diameter of coronary arteries ( arteries supplying blood to the heart)
  • Reduced blood flow to the heart
  • Arrhythmias or irregular beats
  • Increased time between two consecutive heartbeats, known as QT prolongation)
  • Thrombosis or the formation of excessive blood clots
  • A buildup of plaques in arteries, known as Atherosclerosis
  • Shrinking of the arteries

Each of the symptoms mentioned above can eventually lead to a severe cardiac event and even death if treatment is not sought in time. (source: CDC, 2024 (SHS))

Opioids

With the ongoing opioid epidemic in different parts of the world, many people have been exposed to potentially serious heart issues. In addition to triggering an overdose, opioids can also have profound effects on the heart and significantly increase the risk of arterial fibrillation in its users. While prescription opioid pills have been associated with multiple heart issues, their injectable variants are also not too far behind. These injectables are now known to cause heart infections by introducing fungi, bacteria, and other types of germs through the injection site. These germs circulate into the body, eventually entering the heart and damaging its valves. Without a timely diagnosis, an intravenous opioid user may require a replacement of their heart valves to save their life. Ironically, even a valve replacement does not mitigate the risk but only makes the heart more vulnerable to infection in the future.

Stimulants

This category includes many famous prescriptions and illicit drugs, such as methamphetamine, amphetamine, MDMA, or ecstasy. Most of the drugs categorised as psychostimulants exert similar effects on the heart and the rest of the cardiovascular system. These heart-damaging effects attributed to stimulants occur due to their ability to activate the sympathetic system. This system releases adrenaline and prepares the body for fight or flight in dangerous situations. Even though different stimulants use different mechanisms to activate this system, most of them commonly lead to the following effects:  (source: NHS, 2023)

  • High adrenaline levels in the blood
  • Irregular heartbeat
  • Increased heart rate
  • High blood pressure
  • Narrowing of blood vessels

Together, these effects significantly raise the risk of myocardial ischemia, a condition where the blood flow to a part of the heart is drastically reduced. With time, the affected heart muscle dies due to a lack of oxygen, triggering a heart attack. In addition, abusing stimulants for a long time can cause spasms in the heart muscles that may tear the organ’s walls.

Marijuana

As the most famous street drug in the world, many individuals consider marijuana or weed a safe and harmless substance for everyday use. However, the reality is quite different as the drug can induce many side effects in different body parts, including the heart. The type and severity of marijuana’s effects on the heart depend on its consumed quantities.  (source: NIAAA, 2023)

  • At low to moderate doses, marijuana may trigger sympathetic signalling, which increases the heart rate and blood pressure.
  • At high doses, marijuana activates parasympathetic signalling, causing the blood pressure and heart rate to drop significantly.

Researchers have also linked the use of marijuana with cases of the acute coronary syndrome, a disease similar to myocardial ischemia in which the oxygen and blood flow to the heart are reduced to a dangerous extent. In rare cases, marijuana can trigger a heart attack, particularly within 60 minutes of using it. (source: NHLBI, 2022 (AFib))

Over the past few years, the world has been introduced to multiple “legal highs.” With the increase in their popularity, these legal highs, such as synthetic cathinones and synthetic marijuana, are now available in every head shop and convenience store across the country. While drug laws do not explicitly ban a small number of them, almost none have been approved for human consumption and may threaten heart health. 

Synthetic Marijuana

Synthetic marijuana comes in different forms like K2 and Spice and can exert adverse effects on the heart, similar to those of regular marijuana. However, because the synthetic variants of this drug are much more potent, their potential side effects are likely to be more severe. So far, several issues, like dangerously elevated heart rates and heart attacks, have been reportedly linked to some cases of synthetic marijuana abuse, even in teen users. (source: NHLBI, 2022 (HF))

Synthetic Cathinones

Synthetic cathinones, including bath salts, are the most popular substitutes for drugs like MDMA and cocaine and may exert similar effects on the heart, only more severe in intensity. Studies performed on animal models have revealed that using bath salts can elevate blood pressure and heart rate even more than cocaine. A small number of people abusing these synthetic cathinones may develop heart palpitations and chest pains, indicative of cardiovascular distress.

While alcohol and drugs can badly affect the working of the heart, these side effects are not the only thing addicts should fear. Addiction affects physical and mental health, careers, relationships, finances, and so much more. A significant proportion of people lose their friends, families, jobs, and overall health to drugs. So if you or someone you love is struggling with this issue, it is better to find help as soon as possible. [11]

Joining professional rehabilitation is your best way out of an addiction. These facilities allow individuals to work alongside their team to achieve social, psychological, and physical recovery from alcohol and drugs. From medically-supervised detox to individual therapy, a good rehab has all types of modalities to help you or a loved one heal. To learn more about overcoming an addiction, call a rehab center today.

FAQs

Can drugs cause an enlarged heart?
Yes, some drugs do possess the ability to enlarge the heart. A study published in a renowned journal has found that cocaine, in particular, triggers a unique series of events within the body that ultimately lead to heart enlargement. When this drug enters the bloodstream, it activates CaMK, a protein that starts accumulating calcium particles in the heart tissue. This rapid calcium buildup forces the heart to start collecting specific proteins that only exist in the hearts of developing fetuses. As these proteins continue to develop and divide, the heart tissue keeps growing, resulting in cardiac hypertrophy. This mechanism has been evident in even those who only used cocaine habitually to the extent that their heart is no longer able to circulate blood effectively. Eventually, it acquires an irregular pattern of beating called arrhythmia that may lead to cardiac arrest and even death.
What are the symptoms of cocaine heart damage?
Cocaine poses some unique risks to the heart of the users. These risks are closely associated with premature heart attacks along with other cardiovascular issues, even in otherwise healthy people. Due to this strong association, experts commonly call cocaine a “perfect drug for heart attack.” Research comparing people who socially used cocaine at least once a month for a year to those who never used it has tracked the following symptoms in the former:
Stiffer arteries
High blood pressure
Thickened cardiac muscles
 
Apart from the symptoms mentioned above, cocaine also tends to increase the blood clotting tendency, which further increases the risk of a heart attack by blocking arteries.
Can your heart heal from drug abuse?
Yes, it is possible to reverse the heart damage caused by drugs, but only to a certain extent. The results from a particular study reveal that quitting methamphetamine followed by seeking appropriate medical treatment can reverse the effects of this drug on the heart tissue. While this study does indicate a possibility of recovering from drug-induced damage to the heart, keep in mind that the level of improvement may vary depending on individual factors like current health, the type of drug being used, the duration of use, and more.

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