Opioid Overdose: Opioids are commonly associated with nausea and vomiting, especially in the initial stages of use or in overdose situations. The body's reaction to excessive opioid levels can lead to these symptoms among others like drowsiness and respiratory depression.

Benzodiazepine Overdose: While benzodiazepines are less likely to cause nausea and vomiting compared to opioids, they can still induce these symptoms, especially when combined with other substances or in large doses.
Salicylate (Aspirin) Overdose: Salicylates can cause gastrointestinal irritation, leading to nausea and vomiting. This, combined with their easy accessibility, makes them a common cause of overdose.
Acetaminophen Overdose: Although acetaminophen overdose might not initially present with nausea and vomiting, these symptoms can occur, especially as liver damage progresses.

Cocaine Overdose: Cocaine can cause severe cardiovascular and neurological effects, and while nausea and vomiting might not be the primary symptoms, they can occur. Missing a cocaine overdose diagnosis could be fatal due to its potential for causing myocardial infarction, seizures, and stroke.
Tricyclic Antidepressant (TCA) Overdose: TCAs can cause a wide range of symptoms, including nausea and vomiting, but more critically, they can lead to cardiac arrhythmias and seizures, making prompt diagnosis crucial.

Iron Overdose: Iron overdose can cause severe gastrointestinal symptoms, including nausea and vomiting, due to its corrosive effect on the gastrointestinal tract. It's less common but can be seen in cases of accidental ingestion, especially in children.
Theophylline Overdose: Theophylline, used in treating asthma and COPD, can cause nausea and vomiting among other symptoms like seizures and cardiac arrhythmias in overdose situations. Its use is less common, making overdose relatively rare.