Pick a card, any card

This post is inspired by a clinic conversation yesterday. Our clinical question was about which antidepressant to choose.  It can kind of feel like a game at times: you make a random pick,and see what happens. Is there a more evidence based way to go about it?  

The evidence behind SSRIs is a whole different post, but suffice it to say that they have similar efficacy and tolerablity. Citalopram (Celexa), Paroxetine (Paxil), Fluvoxamine (Fluvox), Fluoxetine (Prozac), Sertraline (Zoloft), and Escitalopram (Lexapro) are all available widely.

So how to decide what to prescribe when a patient is sitting in front of you. You could pick based on your favorite commercial, or which drug rep bought the best dinner, but maybe there is a less biased method.

Generally we use patient preference, side effects, and cost as the driving factor in picking among similar medicines.  So I thought I’d review the last two for you here.

Cost is easier.  All of these come in generic forms now.  Citalopram and paroxetine are on the $4 drug list at WalMart. A quick search on GoodRx shows prices around $5 for fluoxetine, $8-10 for sertraline, and $15 for fluvoxamine and escitalopram.

Artwork by Robin D Snyder. Text at the bottom of the screen says: “Certain Side Effects May Occur”.

Now for side effects. All of them can cause weight gain, decreased libido, and diarrhea, which are often pretty important to patients. Scarier side effects are QTc prolongation, and hypotension and anticholinergic effects, which may make you think twice about prescribing to an older patient. You can sort out which side effect is most important to your patient, and then steer clear of the worst offenders.

  • Weight gain: Paroxetine seems to be the worst, anecdotally I have had complaints about citalopram as well.
  • Sexual Dysfunction: A big problem with all of them.  Again, paroxetine is the worst, but none are really great.  Your best bet if this is a big factor for your patient: use bupropion instead of an SSRI.
  • GI side effects: Diarrhea is the most common complaint from a GI standpoint.  Sertraline is the worst offender here.
  • QTc prolongation: Citalopram, Escitalopram, and Fluoxetine are the ones known to cause some QT troubles. The others are probably OK.
  • Hypotension and anticholinergic effects: Again, paroxetine is the troublemaker here, although any can contribute.

Often listed as a side effect is agitation or “activation”. Sometimes I try to use this as a benefit.  If patients are particularly apathetic, or have the psychomotor retardation often seen in major depression, you can use this to your advantage.  I think of fluoxetine and sertraline as being more “activating“, while citalopram and paroxetine are more sedating.  The latter two can be helpful for the anxious patient.

At the end of the day, I don’t know that there is a ton of difference between these. I rely on patient experience and preference to guide my choice more than anything else.


Contraception Myths

Some highlights from my contraception mythbusting crusade.  If only I could get to the Supreme Court…

“The good thing about science is that it’s true whether or not you believe in it.” Neil deGrasse Tyson

For combined Estrogen and Progesterone contraceptives: These prevent ovulation, primarily with the progesterone.  The normal menstrual cycle is below, the cyclic fall and rise of progesterone triggers the LH surge. By keeping this high, negative feedback to the hypothalamus is washed out. No LH surge, no ovulation.  The estrogen is there to recruit more progesterone receptors (so less progesterone is needed), and stabilize the endometrium (less breakthrough bleeding).

menstrual cycle

Ovulation happens at the LH surge. LH is surging because progesterone is low.

Large doses of progesterone only contraceptives (DepoProvera, the MiniPill, and Implants) is enough progesterone to prevent ovulation.  The lower dose progesterone only contraceptives (Mirena/Skyla IUDs, the MiniPill) work by thickening cervical mucus, reduce fallopian tube motility, and thinning the endometrium.

IUDs are not abortifacients.  They actually prevent conception from ever happening: the IUD creates a sterile inflammatory response that is toxic to sperm and ova.  This has been shown in vivo with tubal flushing studies.  Women who are not on contraception can be found to have sperm, non fertilized eggs, and even fertilized, but nonviable eggs in the tubes.  Women with IUDs have fewer of all three: the sperm never get there and fertilization doesn’t happen.

IUDs do not increase the risk of STIs or PID.  There is a slightly higher risk of infection in the first 20 days after insertion. This is either from incompletely sterile technique or if the woman is already infected when the IUD is placed. So make sure your patient is free from cervicitis before inserting an IUD. After that, the risk is no different.  This myth comes from an old IUD, the Dalkon Shield (that parasite-looking thing in the picture below), which DID increase the risk of PID, because it had a multifilament string that acted as a bacterial superhighway.   IUDs

Emergency Contraception is not an abortifacient either.  The EC pills are mostly large doses of progesterone- which works to prevent ovulation, thicken cervical mucus, and impair motility in the fallopian tubes.  Women do not get pregnant if they have had intercourse after ovulation. Sperm lives in the female reproductive tract for up to 6 days after intercourse, and all that time it is making its way up to the fallopian tubes, where fertilization happens.  EC pills prevent ovulation, and are more effective the sooner after unprotected intercourse they are taken (this is why it is helpful for a woman to have it at home before something goes wrong).  If a woman does get pregnant despite taking EC, the pills will not harm the pregnancy.  

Here’s a great table to use when talking about contraception with your patients. Aim to pick a method from the top row: these are the most effective with typical use (because they don’t require the woman to think about anything once in place).  As you move down the rows, preventing pregnancy gets closer and closer to just luck.  And we can do better than that!

contraception effectiveness