Examples of Different Drug Classes

A look at different drug classes such as antibiotics, NSAIDs, and Statins

Drug Classes

A drug class or medication class is a group of medications that may work in the same way, have a similar chemical structure, or are used to treat the same health condition. Within the drug class, your health care provider looks for the specific medication that can best treat your condition. The classes are general categories and medications may appear in more than one drug class if they have a variety of effects or are used with different conditions. Here are examples of several common drug classes.


Antibiotics are a class of medications used to treat infections caused by bacteria. Some frequently prescribed antibiotics are amoxicillin and Zithromax (azithromycin). Antibiotics can be derived from naturally occurring compounds that inhibit bacterial growth. They can also be created synthetically. There are many different types of antibiotics including the following:

  • Beta-lactams, such as penicillins, cephalosporins, and carbapenems, which inhibit cell wall synthesis
  • Drugs that interfere with protein synthesis, such as macrolides, tetracyclines, linezolid, and lincosamides
  • Drugs that interfere with folate synthesis, such as trimethoprim and sulfonamides
  • Drugs that interfere with bacterial nucleic acid synthesis, such as the quinolones and rifampin

More generally, antibiotics can be either bacteriostatic or bacteriocidal. Bacteriostatic antibiotics halt cell division and cell growth. Bactericidal antibiotics directly kill bacteria. For example, rifampin is a bacteriocidal drug whereas antibiotics that interfere with protein synthesis can be bacteriocidal or bacteriostatic.


Antidepressants are a class of medications used to treat the symptoms of depression. Some frequently prescribed antidepressants are Lexapro (escitalopram) and Zoloft (sertraline). They are thought to work by changing how chemicals in the brain called neurotransmitters regulate mood. They are further classed by which neurotransmitter they affect and in what way they do so.

  • Selective serotonin reuptake inhibitors (SSRIs): Includes Prozac (fluoxetine). These drugs help elevate the signal of serotonin.
  • Serotonin norepinephrine reuptake inhibitors (SNRIs): Includes Effexor (venlafaxine). These drugs help elevate the signal of norepinephrine.
  • Tricyclic antidepressants (TCAs): Includes Elavil (amitriptyline): These drugs enhance the signaling of both serotonin and norepinephrine but also affect other chemical messengers, leading to side effects.
  • Monoamine oxidase inhibitors (MAOIs): Includes Nardil (phenelzine). These drugs keep the body from breaking down neurotransmitters.

Nonsteroidal Anti-Inflammatory Drugs (NSAIDs)

Nonsteroidal anti-inflammatory drugs are a class of drugs that have anti-inflammatory, analgesic, and antipyretic (anti-fever) properties. All NSAIDs work by inhibiting the enzyme cyclooxygenase and are commonly available in over-the-counter formulations. Examples of NSAIDs include ibuprofen and aspirin. Although NSAIDs are for the most part safe to take, they do have adverse effects. For example, aspirin commonly causes gastrointestinal upset and can also cause bleeding in some.


Opioids are a class of drugs derived from naturally occurring opium. Opium is harvested from the poppy Papaver somniferum. Classically, morphine has been most widely used in medicine. Other examples of opioids include codeine, heroin, and hydrocodone. Furthermore, there are completely synthetic opioids, including meperidine, fentanyl, methadone, and butorphanol. Opioids are commonly mixed with aspirin or acetaminophen for better pain relief (think Vicodin or Norco).

Opioids work by inhibiting neurotransmitter release thus resulting in pain relief. Opioids also generate a calming or soothing effect. Opioid abuse and dependence have become an increasingly common problem, with countless people misusing both street versions of the drug and prescription opioids. Opioid toxicity can kill by means of respiratory depression.


Statins are a class of medications that inhibit the production of cholesterol in the liver and are used to treat people who have high cholesterol. Some frequently prescribed statins are Lipitor (atorvastatin) and Zocor (simvastatin).

View Article Sources
  • Albertson TE. Chapter 119. Opiates and Opioids. In: Olson KR. eds. Poisoning & Drug Overdose, 6e. New York, NY: McGraw-Hill; 2012. 
  • Gasbarre CC, Schmitt SK, Tomecki KJ. Chapter 230. Antibiotics. In: Goldsmith LA, Katz SI, Gilchrest BA, Paller AS, Leffell DJ, Wolff K. Eds. Fitzpatrick's Dermatology in General Medicine, 8e. New York, NY: McGraw-Hill; 2012.