Ritodrine is a tocolytic drug used to stop labor during childbirth and is most effective when labor only needs to be interrupted for a short amount of time. It is not available in some countries, including the U.S., due to some of the severe side effects and the availability of safer, more effective alternatives. Some maternal health issues can make the drug unsafe, and it is only prescribed for women who are at least 20 weeks pregnant.
The medication works by relaxing the muscles in the body. Unlike typical relaxants, however, it is able to relax the muscle in the uterus responsible for contractions; by hindering these contractions, labor can be delayed. For immediate use, the drug is administered by IV, typically in a hospital. Once labor has been stalled, pill forms of the drug can be taken to temporarily prevent labor from starting up again. The pills can be taken at home under the direction of a doctor and on a very strict schedule; in many cases, a drop in the amount of the drug in a woman's system can cause labor to commence
Fetal lung development does not finish until a few days prior to the 40-week mark, which is the length of a typical pregnancy. Ritodrine is best used in cases where labor only needs to be delayed for 12 to 24 hours. This typically gives steroid injections — used to speed up fetal lung development — time to work. The drug becomes less effective the longer it is taken. This loss of effectiveness is due to something known as tachyphylaxis; the high dosage of ritodrine given in a short period of time causes the body to rapidly build up a tolerance. This, coupled with some of the side effects, is why many doctors choose other drugs to halt premature labor.
Some of the common side effects are blurry vision, dizziness, headaches, nausea, and dry mouth. It can also cause extreme exhaustion. In more serious cases, ritodrine can also cause the mother to have difficulty breathing and may induce anxiety attacks. This drug can also have an effect on the fetus, significantly speeding up the unborn baby's pulse, thus potentially causing fetal distress. While the less serious side effects are most common, the instances of the more severe side effects are unusually high. For this reason, many countries no longer permit ritodrine to treat premature labor.
This drug can also be dangerous for women with certain health issues. Those with high blood pressure and uncontrolled thyroid issues, especially a hyperactive thyroid, can experience many complications. Those with diabetes and most forms of heart disease should also not take it; the drug can increase a woman's heart rate as well as cause a dramatic drop in blood sugar.
Ritodrine passes very quickly into the placenta and can cause additional health issues in the fetus, including physical and mental developmental problems, if the drug is given to a mother less than 20 weeks along in her pregnancy. The drug is considered an option by both the manufacturer and medical professionals only after the 20-week mark. Before taking ritodrine or any other drug to hinder premature labor, a woman should notify her doctor of any preexisting health conditions for both her safety and the safety of the unborn child.