FDA approves Diclegis for the treatment of morning sickness

FDA has approved doxylamine succinate 10 mg, pyridoxine hydrochloride 10 mg (Diclegis, Duchesnay) delayed-release tablets for the treatment of nausea and vomiting of pregnancy (NVP) in women who do not respond to conservative management, including dietary and lifestyle modifications. These modifications include eating several small meals instead of 3 large meals, eating bland foods that are low in fat and easy to digest, and avoiding smells that can trigger nausea.

This is the only treatment for NVP, more commonly known as morning sickness, approved by FDA in more than 30 years. Diclegis, once called Bendectin, was pulled off the market 30 years ago after a safety scare prompted by hundreds of lawsuits claiming birth defects. Although the scare proved to be a false alarm, The Washington Post reported, the manufacturer withdrew the drug because it could not afford to defend itself in court.

FDA granted Diclegis Pregnancy Category A status, which means that the results of controlled studies have not shown an increased risk to an unborn baby during pregnancy. The 2 active ingredients in Diclegis that reduce nausea and vomiting in pregnancy - doxylamine succinate and pyridoxine hydrochloride, or vitamin B₆ - have been recommended as a first-line pharmacotherapy by the American Congress of Obstetricians and Gynecologists (ACOG) guidelines for the last 9 years.

NVP is a medical condition that affects 70% to 85% of pregnant women with symptoms ranging from nausea to severe vomiting and retching that can last throughout the day. Some pregnant women may experience symptoms throughout their pregnancy. For most pregnant women, symptoms generally cease at approximately 16 to 20 weeks. 

Diclegis was studied in 261 women experiencing nausea and vomiting due to pregnancy. Study participants in the clinical trial were at least 18 years old and had been pregnant for at least 7 weeks and up to 14 weeks. Women were randomly assigned to receive 2 weeks of treatment with Diclegis or a placebo. The study results showed that women taking Diclegis experienced greater improvement in nausea and vomiting than did those taking placebo. In addition, observational (epidemiological) studies have shown that the combination of active ingredients in Diclegis does not pose an increased risk of harm to the fetus.

Initially, a patient takes 2 Diclegis delayed-release tablets orally at bedtime (Day 1).  If symptoms persist into the afternoon of Day 2, the patient takes the usual dose of 2 tablets at bedtime that night and then adds 1 tablet the following morning on Day 3. If symptoms still persist on Day 4, the patient takes 1 tablet in the morning, 1 tablet mid-afternoon, and 2 tablets at bedtime. The maximum recommended dose is 4 tablets (1 in the morning, 1 at mid-afternoon, and 2 at bedtime) daily. Diclegis is taken as a daily prescription and not on an as-needed basis to help control symptoms throughout the day.

Nausea and vomiting due to pregnancy usually improve after the first trimester. Healthcare professionals should reassess their patients for continued need for Diclegis as pregnancy progresses.

Drowsiness or sleepiness, which can be severe, are the most common side effects reported by women taking Diclegis. Women should avoid using Diclegis when engaging in activities requiring mental alertness, such as driving or operating heavy machinery, until cleared to do so by their healthcare providers.