Opioids are the medication class most frequently involved in overdose suicides, appearing in roughly 48% of fatal self-poisoning cases in the United States. Antidepressants follow at about 16%, then benzodiazepines at nearly 15%, alcohol at 14%, and anti-seizure medications at around 7%. These numbers reflect 2016 national mortality data published in JAMA Network Open, and most fatal overdoses involve more than one substance.
Opioids Dominate Fatal Overdoses
Opioids carry the highest risk of death in intentional overdose by a wide margin. A person who takes opioids in a suicide attempt is roughly five times more likely to die than someone who attempts self-poisoning without opioids. Translated into practical terms, an estimated 81% of opioid-involved poisoning suicides would not have been fatal if opioids had not been part of the ingestion. This makes opioid access one of the single biggest risk factors for fatal self-poisoning.
The opioid category includes both prescription painkillers and illicit drugs like heroin and illegally manufactured fentanyl. Prescription opioid death rates vary sharply by geography, with West Virginia, Maryland, and Utah recording the highest rates in recent years. Synthetic opioids, primarily fentanyl, have driven the sharpest increases in overdose deaths overall, though not all of those deaths are intentional.
Antidepressants Vary Widely in Toxicity
Antidepressants are involved in roughly 16 to 20% of poisoning suicides, but the risk depends enormously on which type of antidepressant is involved. Older tricyclic antidepressants (TCAs) are far more dangerous in overdose than newer medications. In data from England and Wales, TCAs accounted for 1,088 overdose deaths compared to just 85 for all five common SSRIs combined. The case fatality rate for TCAs was nearly 28 times higher than for SSRIs.
Among TCAs, dosulepin and amitriptyline were the most frequently involved in suicide deaths. Among newer antidepressants, venlafaxine had a toxicity index roughly five times higher than the SSRIs, though still far lower than the tricyclics. Within the SSRI class, citalopram showed a case fatality rate about three times higher than other SSRIs. This difference in lethality is one reason prescribing has shifted heavily toward SSRIs over the past few decades, particularly for patients considered at risk.
Benzodiazepines and Sedatives
Benzodiazepines appear in about 13 to 16% of overdose suicide deaths. However, they are rarely the sole agent. Benzodiazepines become far more dangerous when combined with opioids or alcohol, both of which suppress breathing. The combination effect matters more than the benzodiazepine alone in most fatal cases.
Barbiturates, an older class of sedative now rarely prescribed, carry a notably high lethality when they are involved. Their risk of fatal overdose is over four times the average for other drug classes. The decline in barbiturate prescribing over recent decades has meaningfully reduced their role in poisoning deaths, which illustrates how prescribing patterns directly shape which drugs appear in overdose statistics.
Heart Medications and Diabetes Drugs
Calcium channel blockers, used to treat high blood pressure and heart conditions, are among the most lethal cardiovascular drugs in overdose. They can cause the heart to slow dramatically, drop blood pressure to dangerous levels, and in severe cases trigger cardiac arrest. Their relative risk of fatal overdose is about 2.2 times the average, putting them in the same danger zone as alcohol-involved poisonings.
Beta-blockers pose similar risks in overdose, causing dangerously slow heart rhythms and cardiovascular collapse. Diabetes medications, particularly insulin and drugs that lower blood sugar, also carry a surprisingly high lethality in intentional overdose, with a relative risk roughly 2.6 times the average. These categories receive less attention than opioids or antidepressants but represent a meaningful portion of fatal self-poisoning cases.
Alcohol’s Overlooked Role
Alcohol appears in about 14% of overdose suicide deaths, but this figure is almost certainly an undercount. Roughly 30% of medical examiners and coroners do not test for alcohol during death investigations. Even with that undercount, alcohol doubles the risk of a fatal outcome when present in a self-poisoning attempt. About 34% of alcohol-involved suicide deaths would not have been fatal without alcohol’s contribution, largely because it amplifies the effects of other drugs on breathing and consciousness.
Over-the-Counter Drugs
Acetaminophen (the active ingredient in Tylenol) is the second most common drug involved in toxic ingestions in the United States and accounts for about 7.5% of poisoning admissions. It is widely used in suicide attempts because of its easy availability, but its pattern of harm is unusual. Acetaminophen does not cause immediate sedation or respiratory failure. Instead, it destroys the liver over several days, and people who take it impulsively often survive the acute phase only to face liver failure later. Paradoxically, one study found that accidental overdoses of acetaminophen were more likely to result in death than intentional ones, likely because people who take it deliberately tend to seek or receive medical attention sooner.
The United Kingdom’s experience with acetaminophen (called paracetamol there) offers one of the clearest examples of how simple policy changes can reduce overdose deaths. In 1998, the UK restricted pack sizes so that people could only buy limited quantities at a time, and required blister packaging instead of loose bottles. Deaths from acetaminophen poisoning dropped 21% in the years that followed. Liver transplants due to acetaminophen poisoning fell by 66%. The number of tablets taken in the average overdose decreased by 7%, and overdoses involving large quantities dropped by 17%. Even the number of people showing up to hospitals with liver damage from acetaminophen fell by 30%.
Why Frequency and Lethality Tell Different Stories
A drug can appear frequently in overdose statistics either because it is commonly available or because it is especially deadly, and these are not the same thing. SSRIs, for instance, are involved in many overdose attempts because they are among the most widely prescribed medications in the world, but they rarely cause death on their own. Opioids rank highest in both frequency and lethality. Barbiturates are extremely lethal but now cause fewer deaths simply because far fewer people have access to them.
This distinction matters for prevention. Reducing access to the most lethal agents, whether through prescribing changes, packaging restrictions, or safe storage, consistently reduces overdose suicide deaths. The shift from tricyclic antidepressants to SSRIs, the decline of barbiturate prescribing, and the UK’s paracetamol packaging laws all followed the same principle: when the most dangerous option is harder to reach in a moment of crisis, fewer people die. Most suicide attempts by overdose are impulsive, and even small barriers between a person and a lethal dose can change the outcome.