Doxylamine Succinate and Pyridoxine Hydrochloride

1. INDICATIONS AND USAGE Doxylamine succinate and pyridoxine hydrochloride delayed-release tablets are indicated for the treatment of nausea and vomiting of pregnancy in women who do not respond to conservative management. Limitations of Use Doxylamine succinate and pyridoxine hydrochloride delayed-release tablet has not been studied in women with hyperemesis gravidarum. Doxylamine succinate and pyridoxine hydrochloride delayed-release tablets are a fixed dose combination drug product of doxylamine succinate, an antihistamine, and pyridoxine hydrochloride, a Vitamin B6 analog, indicated for the treatment of nausea and vomiting of pregnancy in women who do not respond to conservative management.

2. DOSAGE AND ADMINISTRATION Take two tablets daily at bedtime. If symptoms are not adequately controlled, the dose can be increased to a maximum recommended dose of four tablets daily (one in the morning, one mid-afternoon and two at bedtime) as described in the full prescribing information. 2.1 Dosage Information Initially, take two doxylamine succinate and pyridoxine hydrochloride delayed-release tablets orally at bedtime (Day 1). If this dose adequately controls symptoms the next day, continue taking two tablets daily at bedtime. However, if symptoms persist into the afternoon of Day 2, take the usual dose of two tablets at bedtime that night then take three tablets starting on Day 3 (one tablet in the morning and two tablets at bedtime). If these three tablets adequately control symptoms on Day 4, continue taking three tablets daily. Otherwise take four tablets starting on Day 4 (one tablet in the morning, one tablet mid-afternoon and two tablets at bedtime). The maximum recommended dose is four tablets (one in the morning, one in the mid-afternoon and two at bedtime) daily. Take on an empty stomach with a glass of water [see Clinical Pharmacology (12.3)]. Swallow tablets whole. Do not crush, chew, or split doxylamine succinate and pyridoxine hydrochloride delayed-release tablets. Take as a daily prescription and not on an as needed basis. Reassess the woman for continued need for doxylamine succinate and pyridoxine hydrochloride delayed-release tablets as her pregnancy progresses. 2.1 Dosage Information Initially, take two doxylamine succinate and pyridoxine hydrochloride delayed-release tablets orally at bedtime (Day 1). If this dose adequately controls symptoms the next day, continue taking two tablets daily at bedtime. However, if symptoms persist into the afternoon of Day 2, take the usual dose of two tablets at bedtime that night then take three tablets starting on Day 3 (one tablet in the morning and two tablets at bedtime). If these three tablets adequately control symptoms on Day 4, continue taking three tablets daily. Otherwise take four tablets starting on Day 4 (one tablet in the morning, one tablet mid-afternoon and two tablets at bedtime). The maximum recommended dose is four tablets (one in the morning, one in the mid-afternoon and two at bedtime) daily. Take on an empty stomach with a glass of water [see Clinical Pharmacology (12.3)]. Swallow tablets whole. Do not crush, chew, or split doxylamine succinate and pyridoxine hydrochloride delayed-release tablets. Take as a daily prescription and not on an as needed basis. Reassess the woman for continued need for doxylamine succinate and pyridoxine hydrochloride delayed-release tablets as her pregnancy progresses.

4. CONTRAINDICATIONS Doxylamine succinate and pyridoxine hydrochloride is contraindicated in women with any of the following conditions: Known hypersensitivity to doxylamine succinate, other ethanolamine derivative antihistamines, pyridoxine hydrochloride or any inactive ingredient in the formulation Monoamine oxidase (MAO) inhibitors intensify and prolong the adverse central nervous system effects of doxylamine succinate and pyridoxine hydrochloride [see Drug Interactions (7.1)]. Known hypersensitivity to doxylamine succinate, other ethanolamine derivative antihistamines, pyridoxine hydrochloride or any inactive ingredient in the formulation (4) Monoamine oxidase (MAO) inhibitors (4, 7)

5. WARNINGS AND PRECAUTIONS Activities requiring mental alertness: Avoid engaging in activities requiring complete mental alertness, such as driving or operating heavy machinery, while using doxylamine succinate and pyridoxine hydrochloride until cleared to do so by a healthcare provider (5.1) Central nervous system (CNS) depressants: Concurrent use with alcohol or other CNS depressants is not recommended (5.1) Anticholinergic actions: Use with caution in patients with asthma, increased intraocular pressure, narrow angle glaucoma, stenosing peptic ulcer, pyloroduodenal obstruction and urinary bladder-neck obstruction (5.2) Interference with urine drug screen: Doxylamine succinate and pyridoxine hydrochloride may interfere with urine screening for methadone, opiates and PCP (5.3) 5.1 Activities Requiring Mental Alertness Doxylamine succinate and pyridoxine hydrochloride may cause somnolence due to the anticholinergic properties of doxylamine succinate, an antihistamine. Women should avoid engaging in activities requiring complete mental alertness, such as driving or operating heavy machinery, while using doxylamine succinate and pyridoxine hydrochloride until cleared to do so by their healthcare provider. Doxylamine succinate and pyridoxine hydrochloride use is not recommended if a woman is concurrently using central nervous system (CNS) depressants including alcohol. The combination may result in severe drowsiness leading to falls or accidents [see Drug Interactions (7.1)] . 5.2 Concomitant Medical Conditions Doxylamine succinate and pyridoxine hydrochloride has anticholinergic properties and, therefore, should be used with caution in women with: asthma, increased intraocular pressure, narrow angle glaucoma, stenosing peptic ulcer, pyloroduodenal obstruction and urinary bladder-neck obstruction. 5.3 Interference with Urine Screen for Methadone, Opiates and Phencyclidine Phosphate (PCP) There have been reports of false positive urine screening tests for methadone, opiates, and PCP with doxylamine succinate/pyridoxine hydrochloride use [see Drug Interactions (7.3)]. 5.1 Activities Requiring Mental Alertness Doxylamine succinate and pyridoxine hydrochloride may cause somnolence due to the anticholinergic properties of doxylamine succinate, an antihistamine. Women should avoid engaging in activities requiring complete mental alertness, such as driving or operating heavy machinery, while using doxylamine succinate and pyridoxine hydrochloride until cleared to do so by their healthcare provider. Doxylamine succinate and pyridoxine hydrochloride use is not recommended if a woman is concurrently using central nervous system (CNS) depressants including alcohol. The combination may result in severe drowsiness leading to falls or accidents [see Drug Interactions (7.1)] . 5.2 Concomitant Medical Conditions Doxylamine succinate and pyridoxine hydrochloride has anticholinergic properties and, therefore, should be used with caution in women with: asthma, increased intraocular pressure, narrow angle glaucoma, stenosing peptic ulcer, pyloroduodenal obstruction and urinary bladder-neck obstruction. 5.3 Interference with Urine Screen for Methadone, Opiates and Phencyclidine Phosphate (PCP) There have been reports of false positive urine screening tests for methadone, opiates, and PCP with doxylamine succinate/pyridoxine hydrochloride use [see Drug Interactions (7.3)].

7. DRUG INTERACTIONS Severe drowsiness can occur when used in combination with alcohol or other sedating medications. (7) 7.1 Drug Interactions Use of doxylamine succinate and pyridoxine hydrochloride is contraindicated in women who are taking monoamine oxidase inhibitors (MAOIs), which prolong and intensify the anticholinergic (drying) effects of antihistamines. Concurrent use of alcohol and other CNS depressants (such as hypnotic sedatives and tranquilizers) with doxylamine succinate and pyridoxine hydrochloride is not recommended. 7.2 Drug-Food Interactions A food-effect study demonstrated that the delay in the onset of action of doxylamine succinate and pyridoxine hydrochloride may be further delayed, and a reduction in absorption may occur when tablets are taken with food [see Dosage and Administration (2), Clinical Pharmacology (12.3)] . Therefore, doxylamine succinate and pyridoxine hydrochloride should be taken on an empty stomach with a glass of water [see Dosage and Administration (2)]. 7.3 False Positive Urine Tests for Methadone, Opiates and PCP False positive drug screens for methadone, opiates, and PCP can occur with doxylamine succinate/pyridoxine hydrochloride use. Confirmatory tests, such as Gas Chromatography Mass Spectrometry (GC-MS), should be used to confirm the identity of the substance in the event of a positive immunoassay result. 7.1 Drug Interactions Use of doxylamine succinate and pyridoxine hydrochloride is contraindicated in women who are taking monoamine oxidase inhibitors (MAOIs), which prolong and intensify the anticholinergic (drying) effects of antihistamines. Concurrent use of alcohol and other CNS depressants (such as hypnotic sedatives and tranquilizers) with doxylamine succinate and pyridoxine hydrochloride is not recommended. 7.2 Drug-Food Interactions A food-effect study demonstrated that the delay in the onset of action of doxylamine succinate and pyridoxine hydrochloride may be further delayed, and a reduction in absorption may occur when tablets are taken with food [see Dosage and Administration (2), Clinical Pharmacology (12.3)] . Therefore, doxylamine succinate and pyridoxine hydrochloride should be taken on an empty stomach with a glass of water [see Dosage and Administration (2)]. 7.3 False Positive Urine Tests for Methadone, Opiates and PCP False positive drug screens for methadone, opiates, and PCP can occur with doxylamine succinate/pyridoxine hydrochloride use. Confirmatory tests, such as Gas Chromatography Mass Spectrometry (GC-MS), should be used to confirm the identity of the substance in the event of a positive immunoassay result.

6. ADVERSE REACTIONS The following adverse reactions are discussed elsewhere in the labeling: Somnolence [see Warnings and Precautions (5.1)] Falls or other accidents resulting from the effect of the combined use of doxylamine succinate and pyridoxine hydrochloride with CNS depressants including alcohol [see Warnings and Precautions (5.1)] The most common adverse reaction with doxylamine succinate and pyridoxine hydrochloride (≥5 percent and exceeding the rate in placebo) is somnolence. (6) To report SUSPECTED ADVERSE REACTIONS, contact Endo at 1-800-828-9393 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trial Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice. The safety and efficacy of doxylamine succinate and pyridoxine hydrochloride were compared to placebo in a double-blind, randomized, multi-center trial in 261 women with nausea and vomiting of pregnancy. The mean gestational age at enrollment was 9.3 weeks, range 7 to 14 weeks gestation [see Clinical Studies (14)] . Adverse reactions for doxylamine succinate and pyridoxine hydrochloride that occurred at an incidence ≥5 percent and exceeded the incidence for placebo are summarized in Table 1. Table 1: Number (Percent) of Subjects with ≥ 5 Percent Adverse Reactions in a 15-Day Placebo-Controlled Study of Doxylamine Succinate and Pyridoxine Hydrochloride (Only Those Adverse Reactions Occurring at an Incidence ≥ 5 Percent and at a Higher Incidence with Doxylamine Succinate and Pyridoxine Hydrochloride than Placebo are Shown) Doxylamine Succinate and Pyridoxine Hydrochloride (N = 133) Placebo (n = 128) Somnolence 19 (14.3%) 15 (11.7%) 6.2 Postmarketing Experience The following adverse events, listed alphabetically, have been identified during post-approval use of the combination of 10 mg doxylamine succinate and 10 mg pyridoxine hydrochloride. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure . Cardiac disorders : dyspnea, palpitation, tachycardia Ear and labyrinth disorders : vertigo Eye disorders : vision blurred, visual disturbances Gastrointestinal disorders : abdominal distension, abdominal pain, constipation, diarrhea General disorders and administration site conditions : chest discomfort, fatigue, irritability, malaise Immune system disorders : hypersensitivity Nervous system disorders : dizziness, headache, migraines, paresthesia, psychomotor hyperactivity Psychiatric disorders : anxiety, disorientation, insomnia, nightmares Renal and urinary disorders : dysuria, urinary retention Skin and subcutaneous tissue disorders : hyperhidrosis, pruritus, rash, rash maculo-papular 6.1 Clinical Trial Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice. The safety and efficacy of doxylamine succinate and pyridoxine hydrochloride were compared to placebo in a double-blind, randomized, multi-center trial in 261 women with nausea and vomiting of pregnancy. The mean gestational age at enrollment was 9.3 weeks, range 7 to 14 weeks gestation [see Clinical Studies (14)] . Adverse reactions for doxylamine succinate and pyridoxine hydrochloride that occurred at an incidence ≥5 percent and exceeded the incidence for placebo are summarized in Table 1. Table 1: Number (Percent) of Subjects with ≥ 5 Percent Adverse Reactions in a 15-Day Placebo-Controlled Study of Doxylamine Succinate and Pyridoxine Hydrochloride (Only Those Adverse Reactions Occurring at an Incidence ≥ 5 Percent and at a Higher Incidence with Doxylamine Succinate and Pyridoxine Hydrochloride than Placebo are Shown) Doxylamine Succinate and Pyridoxine Hydrochloride (N = 133) Placebo (n = 128) Somnolence 19 (14.3%) 15 (11.7%) 6.2 Postmarketing Experience The following adverse events, listed alphabetically, have been identified during post-approval use of the combination of 10 mg doxylamine succinate and 10 mg pyridoxine hydrochloride. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure . Cardiac disorders : dyspnea, palpitation, tachycardia Ear and labyrinth disorders : vertigo Eye disorders : vision blurred, visual disturbances Gastrointestinal disorders : abdominal distension, abdominal pain, constipation, diarrhea General disorders and administration site conditions : chest discomfort, fatigue, irritability, malaise Immune system disorders : hypersensitivity Nervous system disorders : dizziness, headache, migraines, paresthesia, psychomotor hyperactivity Psychiatric disorders : anxiety, disorientation, insomnia, nightmares Renal and urinary disorders : dysuria, urinary retention Skin and subcutaneous tissue disorders : hyperhidrosis, pruritus, rash, rash maculo-papular

8.1 Pregnancy Risk Summary Doxylamine succinate and pyridoxine hydrochloride is intended for the treatment of nausea and vomiting of pregnancy in women who do not respond to conservative management. Maternal risks are discussed throughout the labeling. No increased risk for congenital malformations has been reported in epidemiologic studies in pregnant women. In the U.S. general population, the estimated background risks for major birth defects and miscarriage in clinically recognized pregnancies are 2-4% and 15-20%, respectively. Data Human Data The combination of doxylamine succinate and pyridoxine hydrochloride has been the subject of many epidemiological studies (cohort, case control and meta-analyses) designed to detect possible teratogenicity. A meta-analysis of 16 cohort and 11 case-control studies published between 1963 and 1991 reported no increased risk for malformations from first trimester exposures to doxylamine succinate and pyridoxine hydrochloride, with or without dicyclomine hydrochloride. A second meta-analysis of 12 cohort and 5 case-control studies published between 1963 and 1985 reported no statistically significant relationships between fetal abnormalities and the first trimester use of the combination doxylamine succinate and pyridoxine hydrochloride with or without dicyclomine hydrochloride.