This month a new antidepressant came to market. Viibryd continues the trend of ever stranger new drug names (generic name vilazodone) and comes with the claim that it won’t lead to sexual dysfunction in the vast majority of users. Whether this turns out to be the case will likely determine whether Viibryd is a hugely popular new drug or just another strangely named addition to an already saturated field of SSRI type antidepressants. Viibryd is technically in a class of its own, having both serotonin reuptake properties and functioning as a post synaptic partial serotonin agonist.
The SSRI drugs prevent the reuptake of serotonin from the space between nerve endings, and lead to an increased concentration of serotonin in this space. Viibryd in addition to this function is a partial serotonin agonist. An agonist is any drug that simulates the activity of a chemical in the body. This additional function could at least in theory alter the usually side effects of an SSRI as well as alter its potential benefits.
In two relatively small studies Viibryd was found to be effective as an antidepressant, but had a very low incidence of sexual dysfunction. Specifically the incidence of orgasmic dysfunction in women and ejaculatory delay or dysfunction in men was less than 3% and very near the rates with placebo. The published rates of these side effects with all of the currently available SSRIs, including fluoxitine (Prozac), sertraline (Zoloft), paroxitine (Paxil) and others, as well as with the SNRIs like venlafaxine (Effexor) and Cymbalta are greater than 15%, and in my experience prescribing these drugs are even higher. By far the most common SSRI and venlafaxine side effects are various aspects of sexual dysfunction, especially orgasmic dysfunction. These are common enough and annoying enough that I often see patients in the office who have stopped their antidepressant medications because of their sexual dysfunction side effects.
The major factor that Viibryd is going to have to overcome is that there are several highly effective generic SSRI antidepressants on the market that are available on the discount pharmacy $4./ month offerings. As a branded antidepressant which will almost certainly be much higher priced Viibryd is going to have to show a clear benefit to gain traction in this highly competitive and saturated market. If Viibryd is found by patients and physicians to be as effective as the currently available SSRIs at treatment of depression, and really not cause orgasmic dysfunction in women and have a very low incidence of sexual dysfunction overall it is going to be a nice addition to our options for treatment of depression. I’ll reserve my judgement at this time, as prior releases of new SSRIs were touted as having lower likelyhood of these side effects. I remember the claim that Celexa side effects of sexual dysfunction were low, but in aftermarket experience Celexa (citalopram) turned out to cause only minimal if any less frequent sexual dysfunction that the SSRIs already on the market.
Viibryd is reported to have a bit higher incidence of gastrointestinal side effects than most of the SSRIs, and to avoid these side effects it is recommended that patients taper up fairly quickly in dosage. It will be interesting to see if this leads to taking an extra week or two for clinical efficacy. One of the issues we face in prescribing antidepressants in general is that they don’t work immediately, rather tend to take 2-4 weeks to start to help. Adding another week or two of ramp up in dosing may be a bit of a drawback to acceptance or Viibryd by patients. I expect the role of Viibryd to be as a second choice of an antidepressant in patients who experience bothersome sexual dysfunction on another SSRI, and Viibryd is tried as a way to avoid that problem.
Viibryd was developed by Clinical Data which was acquired by Forrest Laboratories earlier this year. Forrest also has Lexapro and Celexa as branded antidepressants, and is expected to make a big marketing push for this new product. From the surge of drug reps at my office it certainly seems like they are throwing all of their weight behind I’m anxious to see if Viibryd lives up to its marketing hype and really does work without causing sexual dysfunction. If so I expect it to be hugely successful. The market for antidepressants is huge, with Effexor and Cymbalta, two branded SNRIs having sales of over $2 billion annually. Expect the $1.1 billion Forrest paid for Clinical Data to be a bargain if Viibryd works as advertised. I plan to go slow and see how this all pans out.
I am now up to 20 mg viibryd (the dose my gynecologist wanted me to be) after 4 weeks and I have had some gastrointestinal side effects. I also feel the urge to urinate more frequently than usual. I also don’t get as much sleep since taking this compared to 50 mg of Zoloft. I am a 35 year old married female with no children.
That is scary about your sister, Brenda. I hope she is alright. I just started Viibryd about 2 weeks ago. Was on Zoloft (High Dosage) for several years. Tapered off onto this within 7 days. I did realize a gain in sexual interest. Big plus. But I also then spent 4 days with gastro issues after being on this by itself. Today I double by pill strength and am wondering if I will have the gastro issues or if that was from ending the Zoloft. Today I go from 20mg x 2/day to one 40 mg once a day. I was on 60mg of Zoloft (20mg x 3 day) but 20 mg of Viibryd seemed much ‘stronger’ then the Zoloft. I really don’t have another word other then it seems ‘Turbo’ compared to Zoloft. I am a bit worried on taking a 40mg dosage at once after reading Brenda’s story. I would like to keep bladder control and the use of my extremities. I take it for post traumatic stress after the loss of a leg. I don’t need to lose the rest of my digits. I hope that is a freak side effect. I do take what some Doctors consider a high dosage of Moriphine which makes me sleep. I haven’t heard or read of Viibryd causing sleeping as Brenda describes. When I sleep I have two goles in mind…rest my body and to wake up. Took the 40mg now and am going to take a nap. Wish me luck. Doctors orders.
Can I only take the low dose. D I have to take 30 – 40 dose so it can work
Elizabeth: The side effects you describe are typical of SSRI discontinuation syndrome. You must be a fast metabolizer of this drug. DrP.
I’ve been taking Viibryd for about 4 months now. I would say that it definitely does not have the same sexual side effects as other anti-depressants based on my own experience (no desire to somewhat interested). However, I want to slowly decrease my doses and eventually discontinue this medication because I get electrical zaps in my head around the time of my next dose. Any intense emotions like being frustrated or happy or sad make the zaps more intense. If I take my next dose, I’m fine, but I don’t like being reminded in a very intense way it’s time to take my next dose of medicine.
I guess I would take the sexual side effects of other more stable anti-depressants than have this new side effect that is very uncomfortable and that I’ve never had from other types of anti-depressants.
Brenda: Far too complex an issue to try to help. Good luck. DrP.
My sister is having neurological issues, she stopped walking 1 month ago, and has no feeling in her feet. Her hands tremble like Parkinson. She was diagnosed w9ith conversion disorder and clinical depression. Thursday (3 days ago) her PCP changed her antidepressaNT to Viibryd. Today (Saturday) she complained of nausea and dizziness. I got her from the wheelchair to the couch and she passed out and fell on the floor. I called 911 and the hospital admitted her. She is still not awake 6 hrs later. They said loss of function in extremities and loss of bladder control are coomon side effects of viibryd. She is on the step up acclimation, 7 days on low dose and increasing. Have you seen this occur before. My sister is 35 yrs old, and only take vicodin/motrin, clarispodol and antidepressants. No hx of chronic illness only mild scoliosis, and bulging vertabrae. Thank you for your help.