Benzodiazepines and antidepressants are frequently used drugs for anxiety disorders, according to the National Institute of Mental Health. Each class of drug has a different mechanism of action. Health professionals must diagnose a particular type of anxiety and review the medical history of a patient before determining the best drug to prescribe.
Size
The National Institute of Mental Health estimates that among adults ages 18 and older in the United States, each year 15 million have social anxiety disorder, 7.7 million have post traumatic stress disorder, 6.8 million have generalized anxiety disorder, 6 million have panic disorder and 2.2 million have obsessive-compulsive disorder. Almost 75 percent of these people will experience their first episode of anxiety disorder by age 21.5. There were 168.7 million prescriptions for antidepressants, and 87.9 million prescriptions for benzodiazepines in the U.S. in 2009, according to IMS Health, a health information company that tracks prescriptions.
Classes
According to the National Institute of Mental Health, benzodiazepines are a large class of drugs that are widely prescribed because they are safe and have rapid anti-anxiety effects. Extended-release formulations can maximize the effects in some patients, according to a review published in "Current Medical Research and Opinion." Some of the popular brand name benzodiazepines used to treat anxiety include Klonopin for generalized anxiety disorder and social phobia, Xanax for generalized anxiety disorder and panic disorder, and Ativan for panic disorder.
The National Institute of Mental Health acknowledges selective serotonin reuptake inhibitors, known as SSRIs, and serotonin-norepinephrine reuptake inhibitors, or SNRIs, as newer types of antidepressants that can treat anxiety disorders because of their safety and effectiveness. Zoloft, Celexa, Paxil, Lexapro and Prozac are brand name SSRIs used to treat obsessive compulsive disorder, post traumatic stress disorder, social phobia and panic disorder. Effexor is a brand name SNRI used to treat generalized anxiety disorder and social phobia.
Features
Benzodiazepines, SSRIs and SNRIs enhance the activity of chemical messengers in the brain called neurotransmitters, including GABA, serotonin and norepinephrine. Each drug within its class may differ in how it binds to receptors on nerve cells in the brain, and its effect, potency, and elimination or half-life. Each drug may also differ in absorption into the body distribution within the brain, and how it is metabolized.
Precautions
Benzodiazepines can create dependence and withdrawal symptoms, including seizures. Dosages should be reduced over several months, or there could be a risk for relapse. Benzodiazepines also have risk for over-sedation and suicide, particularly among people with severe depression. People taking benzodiazepines should not drive a car or operate dangerous machinery.
Antidepressants should be taken for several months or longer to be effective. When discontinuing treatment, a gradual decrease in dosage is recommended to reduce the risk of adverse events such as dizziness, confusion and headaches, and prevent the re-emergence of anxiety symptoms.
Adverse Reactions
Common adverse reactions to benzodiazepines include sedation, fatigue and dry mouth, whereas adverse reactions to antidepressants are headaches, nausea, diarrhea and insomnia.
References
- National Institute of Mental Health: What Medications Are Used to Treat Anxiety Disorders?
- National Institute of Mental Health: The Numbers Count: Mental Disorders in America
- IMS Health: Top Therapeutic Classes by U.S. Dispensed Prescriptions
- National Institute of Mental Health: Mental Health: A Report by the Surgeon General
- "Current Medical Research and Opinion"; Benzodiazepines Anxiety Disorders; Michael Kaplan, E.; Jun 2005
