NSG 502 Week 1 Discussion Board Riviera

Venlafaxine is a serotonin norepinephrine reuptake inhibitor used mainly for patients struggling with depression. I chose to investigate this medication further because although I see it prescribed very frequently on the adolescent psychiatric unit I work on, I feel that I do not have a vast understanding of its neuroscience in relation to its value. I am particularly interested in learning more about this drug class and medication because of its theoretical increased rate of remission and increased onset of action time when compared to the typical first line SSRI medications used for depression. When patients are experiencing depression and feeling desperate, an onset time of 2-4 weeks compared to the 4+ weeks it can take other antidepressants to improve mood can be lifesaving.

SNRI’s are known as dual acting medications, although they actually work on norepinephrine, serotonin, and partially dopamine. They inhibit both the serotonin and norepinephrine transporters resulting in increased availability of serotonin and norepinephrine at the synapse. Dopamine is inactivated by norepinephrine reuptake in the prefrontal cortex, therefore this medication can increase dopamine in this area additionally leading to an improved mood (Stahl, 2013). Due to this action venlafaxine is considered a potent serotonin and norepinephrine transport antagonist, with additional but reduced dopamine reuptake antagonism.

Venlafaxine is almost completely absorbed after oral administration with food intake being irrelevant. It is weakly protein bound (27%), and is primarily metabolized by the liver. Effexor is metabolized by CYP2D6 and is converted into the active metabolite O-desvenlafaxine. The parent drug has a 3-7 hour half life, while it’s metabolite has a 9-13 hour half life (Stahl, 2017). It is ultimately excreted through the renal system (Schatzberg & Debattista, 2015).

This drug class has improved safety and tolerability when compared to TCAs, and MAOIs. SNRIs are more selective in the receptors that they target resulting in a decreased affinity for histamine, adrenergic, and cholinergic receptors and therefore less side effects such as weight gain, sedation, orthostatic hypotension, and dry mouth (Schatzberg & Debattista, 2015). Most side effects stem from the increases in serotonin or norepinephrine in areas the drug was not prescribed to target. This can include insomnia stemming from the action of serotonin on sleep centers, and norepinephrine’s effect on sweating and blood pressure. Notable side effects include headache, nervousness, insomnia, diarrhea, nausea, sexual dysfunction, sweating, and high blood pressure. Many side effects can be transient and resolve in 2-3 weeks therefore patients are encouraged to wait and see if side effects resolve prior to altering treatment (Stahl, 2017). The most significant side effects associated with the use of Venlafaxine are increased blood pressure and nausea. The increase in blood pressure associated with the use of SNRIs is related to the increase of norepinephrine available at the synapse. This risk is dose dependent and it is important to monitor blood pressure for patients taking this medication and prior to treatment initiation. The second most troublesome side effect, nausea, can be improved by utilizing the extended release formulation of venlafaxine which can be administered once daily for improved compliance and tolerance (Stahl, 2017).

Venlafaxine doses should be lowered for patients with renal or hepatic impairment. It is also important to taper doses slowly when discontinuing to prevent withdrawal reactions. Drug interactions can include an increased risk of bleeding with anticoagulants, interference of analgesic actions of drugs such as codeine, fatal serotonin syndrome with MAOIs, and an increased risk of seizure when combined with tramadol. There is also evidence that Effexor can increase Haldol levels by effecting excretion (Stahl, 2017). As with many antidepressants the SNRIs come with a black box warning for increased suicidality in children, adolescents, and young adults. For this reason it is critical to monitor patients for suicidal thoughts and intent.

Venlafaxine is FDA approved for the treatment of depression, generalized anxiety disorder, social anxiety disorder, and panic disorder. It is also commonly prescribed for posttraumatic stress disorder and premenstrual dysphoric disorder (Stahl, 2017). It has been shown to improve ADHD, and numerous studies have concluded that it may be a safe and effective option for improving neuropathic pain (Aiyer et al., 2016).

Aiyer, R., Barkin, R. L., & Bhatia, A. (2016). Treatment of neuropathic pain with venlafaxine: A systematic review. Pain Medicine. https://doi.org/10.1093/pm/pnw261

Alan F Schatzberg, & D. M. Charles DeBattista, (2015).  Manual of Clinical  Psychopharmacology; 8th edition. Arlington: American Psychiatric Publishing.

Stahl, S. M. (2017). Stahl’s essential Psychopharmacology, Prescriber’s guide (6th ed.). Cambridge University Press.

Stephen M. Stahl, (2013). Stahl’s Essential Psychopharmacology Neuroscientific Basis and Practical Applications; 4th Edition. New York: Cambridge University Press.

You did a great job on your post, very extensive about Venlafaxine (Effexor, Effexor XR). One of the benefit, it is both serotonin and norepinephrine reuptake inhibitor. It is FDA approved and can be used for patients that have depression, generalized anxiety disorder, social anxiety disorder which goes hand in hand with GAD, and panic disorder. If patients have more than one diagnoses that I mentioned above Venlafaxine would be one of the best choice for them. “Potential advantages are patients with comorbid anxiety. Patients with depression may have higher remission rates on SNRIs than on SSRIs” (Stahl, 2017, P. 789). Patients with depression that SSRIs don’t work for them, might have a better chance of an SNRI like Venlafaxine that will work. It is the preferred SNRI treatment for depression. Venlafaxine XR is another depressant medication that can be given once a day to reduce side effects of nausea and patients compliance. It has no habit forming, so it cannot be addictive. Venlafaxine XR comes in capsules for patients that cannot swallow whole tablets, especially children and elderlies. Capsules of the medication can be open and sprinkle into a spoon of applesauce or ice cream for them. Providers need to be careful in prescribing it for patients that have high blood pressure and heart problem. Again with this medication, providers have to outweigh the benefits and the risks with their patients.

Carline

Reference:                                          

Stahl, S.M. (2017). Stahl’s Essential Psychopharmacology Prescriber’s Guide.  

(6th Ed.). Cambridge University Press: New York, NY. ISBN 978-1-316-61813-4