MgSO4 is the DOC for tocolysis?

[lama]

According to UW, Magnesium Sulfate is the drug of choice (over ritodrine or terb) for tocolysis... WTF!

So I look up "tocolytics" on UTD and read the following about MgSO4: "... (Magnesium sulfate)... has failed to demonstrate any benefit compared to placebo for the prolongation of pregnancy. A Cochrane review of 23 trials concluded that there was no evidence of a clinically important tocolytic effect for magnesium sulfate..."

Anyone else see this question or have any others like it?

 

[ucbdancn00]

According to UW, Magnesium Sulfate is the drug of choice (over ritodrine or terb) for tocolysis... WTF!

So I look up "tocolytics" on UTD and read the following about MgSO4: "... (Magnesium sulfate)... has failed to demonstrate any benefit compared to placebo for the prolongation of pregnancy. A Cochrane review of 23 trials concluded that there was no evidence of a clinically important tocolytic effect for magnesium sulfate..."

Anyone else see this question or have any others like it?

If i'm not mistaken, MgSO4 works in a way to outcompete Calcium from binding to approrpriate smooth muscle contraction units. In this way, it allows relaxation....I don't believe it actually "prolongs" the pregnancy though...which may be in what the Cochran trials were referring to. (latent period > 20 hours (primigravids), 2nd stage > 2 hours), rather it just kicks the contractions down a couple of notches.

However, in the clinical setting i heard terbutaline constantly being used as the main tocolytic; from my reading I have heard that MgSO4 can be used also, but is not indicated in those with a history of renal disease or neuropathy (ie, remember that elevated Mg can lead to decreased DTR)..

obviously i don't imagine the cochrane reviews to be wrong.....I would imagine that the patient who had a history of cardiac issues, diabetes, etc would not want a B-agonist being used.


just a couple of thoughts, hope it helps...

ucb

 

[lama]

If i'm not mistaken, MgSO4 works in a way to outcompete Calcium from binding to approrpriate smooth muscle contraction units. In this way, it allows relaxation....I don't believe it actually "prolongs" the pregnancy though...which may be in what the Cochran trials were referring to. (latent period > 20 hours (primigravids), 2nd stage > 2 hours), rather it just kicks the contractions down a couple of notches.

However, in the clinical setting i heard terbutaline constantly being used as the main tocolytic; from my reading I have heard that MgSO4 can be used also, but is not indicated in those with a history of renal disease or neuropathy (ie, remember that elevated Mg can lead to decreased DTR)..

obviously i don't imagine the cochrane reviews to be wrong.....I would imagine that the patient who had a history of cardiac issues, diabetes, etc would not want a B-agonist being used.


just a couple of thoughts, hope it helps...

ucb

Yeah, good points. UW mentions the part about cardiac issues/DM. But my point is that they are calling it " The drug of choice".... I don't think so. Funny thing is, the patient in the question didn't have cardiac issues or DM. Oh well...

 

[sponch]

I think it comes down to two factors. One is that we don't really have a good drug for tocolysis. The other is that mag is benign compared to beta mimetics. It basically comes down to "we don't have a good treatment option so we're going to throw a drug at you that works at least theoretically." The corrollary being "since we don't have good data on which is drugs are better, we'll start with someone that is least likely to mess you or your baby up". Viola, mag sulfate. A cheap drug. Toxicity easily managed with checking DTRs. Not as hard on the baby as beta mimetics.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=Abstract&list_uids=12825006&query_hl=2&itool=pubmed_docsum

At our institution, we start off with mag sulfate as first line. If it doesn't work, we're not surprised and cross our fingers. From what an MFM told me, oral tocolysis is the pharmaceutical equivalent of cervical cerclage -- it's just a finger in the dike. The only thing that sucks worse than preterm labor is our ineptitude when it comes to managing it.

 

[Shah_Patel_PT]

According to UW, Magnesium Sulfate is the drug of choice (over ritodrine or terb) for tocolysis... WTF!

So I look up "tocolytics" on UTD and read the following about MgSO4: "... (Magnesium sulfate)... has failed to demonstrate any benefit compared to placebo for the prolongation of pregnancy. A Cochrane review of 23 trials concluded that there was no evidence of a clinically important tocolytic effect for magnesium sulfate..."

Anyone else see this question or have any others like it?

Ritodrine used to be the drug of choice...But since 1 year it is no longer FDA approved as a first choice drug for tocolysis...

Hence Mag sulfate is DOC...