Which type of stimulant is commonly injected, inhaled, or taken as tablets?

Amphetamines are a class of stimulant drugs that are known for their ability to increase focus, energy, and alertness. They can be administered in various ways, including injection, inhalation, and oral tablets, which makes them versatile in terms of consumption methods. This ability to be taken in multiple forms contributes to their widespread use, both medically and recreationally.

Amphetamines work by increasing the levels of certain neurotransmitters in the brain, particularly dopamine and norepinephrine, which enhances mental performance and provides stimulating effects. They are commonly prescribed for conditions such as ADHD and narcolepsy, but they are also misused for their performance-enhancing effects.

In contrast, while caffeine can be consumed in various forms, it is typically ingested orally and does not share the same level of potency as amphetamines. Narcotic analgesics are primarily used for pain relief and do not generally have stimulant properties, and beta blockers are used to manage cardiovascular issues and anxiety, not as stimulants. Thus, amphetamines uniquely fit the criteria laid out in the question.