What Are The Side Effects Of Anxiety Medications?
January 1, 2015 Treatments / Therapy

25504795374_bf04f94a4f_nThe problem with prescription medications for anxiety is that they have significant side effects, most of them benign, some of them severe, and a minor portion of them life-threatening. For a medical doctor prescribing these medications for their patients with severe anxiety, much of the medical guidance is managing the treatment-emergent side effects of these medications. The following includes the different classes of medications used to treat anxiety disorders, and also includes the inherent side effect profiles of each class, and the risks involved with taking these medications (Carandang, 2014; Stahl, 2008):


Selective serotonin reuptake inhibitors (SSRI) are effective for generalized anxiety disorder, panic disorder, social phobia, post traumatic stress disorder, and obsessive compulsive disorder. SSRIs increase the serotonin neurotransmitter concentrations in the synapse by blocking the reuptake of serotonin into the presynaptic cleft. SSRIs include sertraline (brand name Zoloft), fluoxetine (Prozac), citalopram (Celexa), paroxetine (Paxil), fluvoxamine (Luvox), and escitalopram (Lexapro). The common side effects of SSRIs include insomnia, loss of libido, anorgasmia, agitation, anxiety, myoclonus, apathy, diarrhea, gastrointestinal upset, nausea, and vomiting. Less common, yet serious adverse effects include suicidal thoughts, hyponatremia, and serotonin syndrome.

Clinically, SSRIs are the most prescribed medication for anxiety, as it is effective for long-term treatment of anxiety and has a relatively favorable side effect profile, when compared to the other medications prescribed for anxiety. SSRIs are also easy to dose. The problem with SSRIs is that it can take weeks before clinical effects of decreased anxiety are noticed. Also, the first few weeks on an SSRI can be activating…the patient may become more anxious and irritable. Therefore, clinicians sometimes prescribe benzodiazepines on a short term basis until the SSRI clinical effect is realized. Another major problem is that SSRIs are associated with an increase risk of suicide attempts in children, adolescents and young adults (Tandt et al., 2009), especially in the first few weeks of initiating treatment. If you are in this younger age group and the doctor is prescribing an SSRI for anxiety, then the doctor needs to follow you closely- as in weekly visits for at least the 1st month of treatment.


Serotonin norepinephrine reuptake inhibitors (SNRI) are effective for generalized anxiety disorder (GAD), panic disorder, social phobia, post traumatic stress disorder (PTSD), and obsessive compulsive disorder (OCD). Like SSRIs, SNRIs increase the serotonin neurotransmitter concentrations in the synapse by blocking the reuptake of serotonin into the presynaptic cleft. In addition, SNRIs increase the norepinephrine (noradrenaline) neurotransmitter concentrations in the synapse by blocking the reuptake of norepinephrine into the presynaptic cleft. SNRIs include venlafaxine (Effexor), desvenlafaxine (Pristiq) and duloxetine (Cymbalta). Common side effects of SNRIs include insomnia, dry mouth, blurred vision, constipation, urinary retention, loss of libido, anorgasmia, tremor, changes in blood pressure and heart rate, agitation, anxiety, myoclonus, apathy, diarrhea, gastrointestinal upset, nausea, and vomiting.

Clinically, SNRIs, particularly venlafaxine, can cause more activation than SSRIs, particularly the first few weeks of starting on it. It seems to be related to dosing, so it is recommended that when starting an SNRI, to start at low dose, and increase the dose slowly. Benzodiazepines can also help to address this activation side effect, and then discontinue the benzodiazepine when the SNRI starts treating the anxiety symptoms a few weeks later.


Benzodiazepines are effective in the short term for GAD, social phobia, and panic disorder. In specific phobia, benzodiazepines are effective as adjunctive treatment to exposure therapy. Benzodiazepines should only be used in PTSD with caution, as the efficacy is questionable in PTSD and also many patients with PTSD abuse alcohol and/or substances. In OCD treatment, benzodiazepines are only prescribed as adjunctive treatment to antidepressants. Benzodiazepines enhance the function of the GABA neurotransmitter. Benzodiazepines include lorazepam (Ativan), clonazepam (Klonopin), alprazolam (Xanax), and diazepam (Valium). Common side effects include drowsiness, dizziness, tremor, poor concentration, and high addictive potential.

Clinically, benzodiazepines should be used with caution, given the addictive potential of the drug. Also, after using benzodiazepines for long term, discontinuing the drug can lead to withdrawal symptoms that include anxiety. The anxiety from withdrawal from benzodiazepines can be worse than the anxiety that the medication was started for in the first place. But of all the medications for anxiety, benzodiazepines have the most rapid effect…anxiety relief can occur in minutes after ingestion. For even faster effect (to extinguish a panic attack), lorazepam can be placed under the tongue (left to dissolve) for a sublingual placement, where the drug is absorbed into the bloodstream directly to the brain. (please only do this if your doctor prescribes and directs you to do this)

CAUTION: benzodiazepine use in the elderly is associated with a 50% increase in the risk of dementia (Billioti de Gage et al., 2012). Benzodiazepines should be avoided in the elderly.


Tricyclic antidepressants are effective for panic disorder and OCD (particularly clomipramine). TCAs regulate serotonin and/or noradrenaline in the brain. However, TCA use is limited due to the side effect profile. Common side effects include sedation, dry mouth, blurred vision, constipation, urinary retention, dizziness, and weight gain. Less common side effects include cardiac arrhythmias/arrest. Overdose on TCAs is usually fatal, which has limited the prescription of TCAs.

Clinically, TCAs are not prescribed often, as overdose can be fatal. TCAs were often prescribed for anxiety in the past. But with the introduction of Prozac in the 1980’s, SSRIs have been favored over TCAs, given the more favorable side effect profile of SSRIs.


Monoamine Oxidase Inhibitors are effective for panic disorder and OCD, but their use has been limited due to the side effect profile and adherence to a strict tyramine-free diet (otherwise, high blood pressure results). MAOIs block the effect of a brain enzyme, monoamine oxidase, preventing the breakdown of serotonin and noradrenaline. MAOIs include phenelzine (Nardil) and tranylcypromine (Parnate). Hypertension (increase in blood pressure) can occur from combining MAOIs with decongestants, stimulants, TCAs, SNRIs, norepinephrine reuptake inhibitors, norepinephrine dopamine reuptake inhibitors, and appetite suppressants. And if you do not exclude tyramine from their diet, a tyramine hypertensive crisis may occur when taking an MAOI.

Clinically, MAOIs are almost never prescribed, given the restrictions to adhere to a tyramine-free diet, and the resultant hypertensive crisis that may occur when ingesting a food rich in tyramine. With the SSRIs and SNRIs having a more favorable side effect profile for anxiety disorders, resorting to MAOIs are rarely needed.

Beta Blockers

Beta blockers are effective for discreet types of social phobia, such as performance anxiety. Beta blockers block adrenaline receptors, which in turn decreases heart rate. A beta blocker commonly used is propanolol. Common side effects include changes in blood pressure, changes in heart rate, and decrease blood pressure.

Clinically, beta blockers taken before a performance (for those with stage fright) can help to keep you calm in order to expose yourself to an audience. It is advisable to take a test dose of the beta blocker before the actual performance, as you need to see if you can tolerate this medication without side effects.


Buspirone (Buspar) is effective for GAD. Buspirone enhances the activity of serotonin. Dizziness, nausea, and vomiting are common side effects of buspirone. Clinically, buspirone is well tolerated, and does not have many side effects. Unfortunately, buspirone may not be effective at decreasing anxiety symptoms, and this is the reason why many clinicians do not prescribe it.

Alpha(2)delta Ca++ channel modulators

Gabapentin (Neurontin) and Pregabalin (Lyrica) are alpha 2 delta ligands.

Gabapentin and pregabalin are effective for GAD, social phobia, and panic disorder. Gabapentin and pregabalin decrease glutamate, norepinephrine, substance P and calcitonin gene-related peptide in the brain. Common side effects include dizziness, fatigue, drowsiness, weight gain. Clinically, gabapentin and pregabalin are generally well tolerated without significant side effects. Unfortunately, their clinical effect on decreasing anxiety is questionable.


D-cycloserine (Seromycin) is effective in specific phobia as an adjunct to exposure therapy. D-cycloserine affects glutamate in the brain. Common side effects include drowsiness, dizziness, headache, or tremor. Serious, but rare side effects include weakness, mental (mood) changes, numbness, tingling, and seizures. Call your doctor immediately if any of the following rare and serious side effects occur: swelling of the ankles and feet, fatigue, pale skin, irregular heart beat, allergic rash, itching and swelling, and difficulty breathing.

The above summarizes the different classes of medications prescribed for anxiety. The side effect profiles of these prescription medications for anxiety are not benign, and require medical guidance from a doctor. If you want to consider alternatives to prescription medications for anxiety, read my book on anxiety, Anxiety Protocol. We have also developed a natural supplement for anxiety, KalmPro, which contains ingredients that research studies show are effective and safe for anxiety. And when compared to prescription medications for anxiety, natural supplements for anxiety have less side effects, are less expensive, have less stigma, and do not require a doctor visit. Certainly, if you have a severe case of anxiety or if your anxiety has not responded to psychotherapy, then you need to see a doctor and most likely need prescription medication. Finally, if you have questions and want to find out more about anxiety, you can find all your answers at, a hub for all things anxiety.

photo credit: pills via photopin (license)

References: SelectShow
Leave a Reply