Taipei, Nov. 9 (CNA) The Food and Drug Administration (FDA) is mulling a ban on ritodrine, a drug commonly used in Taiwan to suppress preterm labor, given that the European Union has done so for years due to hazardous side effects on expectant mothers.
Some obstetricians are questioning the possible ban, however, urging the government to find viable substitutes before it is introduced.
Hung Kuo-teng, head of the FDA's Medicinal Products Division, told CNA on Monday that the European Medicines Agency (EMA) in 2013 issued a report on its review of medicines called "short-acting beta-agonists" when they are used as tocolytics (medicines that suppress labor contractions).
The EMA found there was a risk of serious cardiovascular side effects to both the mother and unborn baby when high-dose short-acting beta-agonists are used in "obstetric indications," such as for suppressing premature labor or excessive labor contractions.
Given the cardiovascular risk and very limited data on the effectiveness of the oral and suppository forms of these medicines, the EU report concluded that their benefit-risk balance was not favorable and should no longer be used in obstetric indications.
Based on the EU's ban, the FDA in 2013 launched a risk evaluation of the beta-agonists used in oral or suppository forms for the treatment of preterm labor, such as ritodrine, Hung said.
At that time, the experts invited to join the review came to the conclusion that ritodrine is essential as a tocolytic in Taiwan because there is no effective substitute for it.
The experts decided that a review of beta-agonist tocolytic agents be resumed five years later, but it was not initiated until this October, when the FDA informed the medical care sector of the launch of the assessment, Hung said.
The latest evaluation is expected to produce results by the end of the year, when the FDA will decide whether or not to ban the use of ritodrine in oral form to suppress preterm birth, he said.
According to Hung, beta-agonists relax muscles of the airways, causing the widening of airways, resulting in easier breathing. They were developed to treat high blood pressure, asthma, and pulmonary edema before accidentally being discovered as effective in easing excessive uterine contractions.
Over the past decade, more than 1.3 million oral tablets of ritodrine (trade name Yutopar) -- a medication covered by the national health insurance (NHI) system -- have been prescribed every year for the care of pregnant women in Taiwan, according to FDA data.
From 1998 to 2014, nine patients were reported to have developed severe side effects after taking ritodrine in oral or injectable forms, including three who ended up in critical condition before recovering, statistics from the FDA-run reverse drug events reporting system showed.
Doctors were concerned about a ban of the drug, the most commonly prescribed tocolytic drug in Taiwan.
Hung Tai-ho, a resident physician in the Ob-Gyn department of Chang Gung Memorial Hospital, estimated there were 40,000 to 50,000 pregnant women in Taiwan a year who needed preterm labor treatment, judging by the 10 percent rate of premature birth in the country.
Under the NHI system, most obstetricians would prescribe ritodrine in oral form to pregnant patients as a "defense" measure when they develop regular uterine contractions, even if the chance of them having a preterm birth was no more than 30 percent, Hung Tai-ho said.
With that in mind, the government should not suddenly ban ritodrine without any effective substitutes because it would leave physicians unable to offer any medicine to patients in pregnancy, argued Taiwan Association of Obstetrics and Gynecology President Huang Ming-chao.
It could also lead to medical disputes as other drugs known to be effective in suppressing preterm labor but not approved to treat the condition would be prescribed for off-label use to fill the gap, Huang said.
