Text adapted from: "The adult patient with an anxiety disorder," in Psychiatry in primary care by Alina R. Brotea and Richard Swinson (CAMH, 2019).
Medications are a common treatment for anxiety disorders, and should be used when non-pharmacological interventions have not been helpful or when it is expected that non-pharmacological treatment alone will not suffice, such as when patients present with moderate to severe symptoms.
First And Second-line Medication
Recommended medications for anxiety disorders fall into the following groups:
- Atypical antipsychotics
- Mood stabilizers
Antidepressants are the first-line medications in the treatment of anxiety disorders. Anxiolytics may be used for a brief duration, but only if needed while an antidepressant is being initiated and titrated up. Atypical antipsychotics, mood stabilizers and anticonvulsants are used mainly to augment antidepressants.
First- and second-line medications are identified in the Canadian clinical guidelines for treating anxiety disorders (Katzman et al., 2014). Table 1 summarizes these medications. Table 2 lists usual daily dosing ranges of select antidepressants.
All antidepressants have been shown to reduce anxiety symptoms. SSRIs and SNRIs are effective in treating panic disorder, agoraphobia, social anxiety disorder and generalized anxiety disorder. There is also evidence for noradrenergic and specific serotonergic antidepressants (NaSSA). The tricyclic antidepressants (TCA), monoamine oxidase inhibitors (MAOI) and reversible inhibitors of monoamine oxidase A (RIMA) are effective as well, but they are less well tolerated than SSRIs and SNRIs, and are reserved for later choice.
For anxiety disorders, start antidepressants at a very low dose. Patients with anxiety disorders can be extremely intolerant of the side-effects of agitation and akathisia that may occur at the onset of treatment. To start, use the lowest available dose of SSRIs (e.g., escitalopram, 5 mg daily) or SNRIs (e.g., venlafaxine XR, 37.5 mg daily), and titrate up as clinically indicated and tolerated. It is better to start at a low dose with gradual increases over a long period than it is to challenge patients with doses they cannot tolerate because that can lead to frequent medication switching and discontinued treatment. The ultimate effective dose is usually the same as for major depression, or even higher. Patients with anxiety disorders often need prolonged treatment before the desired results are achieved.