1.1 Bacterial Vaginosis

SOLOSEC is indicated for the treatment of bacterial vaginosis in female patients 12 years of age and older [see Use in Specific Populations (8.1) and Clinical Studies (14)].

1.2 Trichomoniasis

SOLOSEC is indicated for the treatment of trichomoniasis caused by Trichomonas vaginalis in patients 12 years of age and older. Because trichomoniasis is a sexually transmitted disease with potentially serious sequelae, treat partners of infected patients simultaneously in order to prevent reinfection [see Dosage and Administration (2.2) and Clinical Studies (14.2)].

1.3 Usage

To reduce the development of drug-resistant bacteria and maintain the effectiveness of SOLOSEC and other antibacterial drugs, SOLOSEC should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.

2.1 Recommended Dosage for Bacterial Vaginosis

The recommended dosage of SOLOSEC for the treatment of bacterial vaginosis in female patients 12 years of age and older is a single 2-gram packet of granules taken once orally, without regard to the timing of meals [see Clinical Pharmacology (12.3)].

2.2 Recommended Dosage for Trichomoniasis

The recommended dosage of SOLOSEC for the treatment of trichomoniasis in patients 12 years of age and older is a single 2-gram packet of granules taken once orally, without regard to the timing of meals [see Clinical Pharmacology (12.3)]. Since trichomoniasis is a sexually transmitted disease, treat sexual partners with the same dose and at the same time [see Indications and Usage (1.2)].

2.3 Instructions for the Preparation and Administration of SOLOSEC

• Open the SOLOSEC packet by folding over the corner (marked by an arrow) and tearing across the top.
• Sprinkle the entire contents of the SOLOSEC packet onto applesauce, yogurt or pudding [see Clinical Pharmacology (12.3)]. The granules will not dissolve. Consume all of the mixture within 30 minutes without chewing or crunching the granules. A glass of water may be taken after the administration of SOLOSEC to aid in swallowing.
• The granules are not intended to be dissolved in any liquid.
• Avoid consumption of alcoholic beverages and preparations containing ethanol or propylene glycol during treatment with SOLOSEC and for at least 2 days after completing therapy [see Adverse Reactions (6.2), Drug Interactions (7.2), and Clinical Pharmacology (12.3)].

5.1 Vulvovaginal Candidiasis

The use of SOLOSEC may result in vulvovaginal candidiasis. In controlled clinical trials of non-pregnant women with bacterial vaginosis, vulvovaginal candidiasis developed in 19/197 (9.6%) of patients who received 2 g SOLOSEC and 4/136 (2.9%) subjects who received placebo. In a controlled clinical trial of non-pregnant female patients with trichomoniasis, vulvovaginal candidiasis developed in 2/74 (2.7%) of patients who received 2 g SOLOSEC and 0/73 (0%) subjects who received placebo [see Adverse Reactions (6.1)]. Symptomatic vulvovaginal candidiasis may require treatment with an antifungal agent.

5.2 Potential Risk for Carcinogenicity

Carcinogenicity has been seen in mice and rats treated chronically with nitroimidazole derivatives which are structurally related to secnidazole. It is unclear if the positive tumor findings in lifetime rodent studies of these nitroimidazoles indicate a risk to patients taking a single dose of SOLOSEC to treat bacterial vaginosis. Avoid chronic use of SOLOSEC [see Nonclinical Toxicology (13.1)]

5.3 Risk of Development of Drug Resistance

Prescribing SOLOSEC in the absence of proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and increases the risk of the development of drug-resistant bacteria.

6.1 Clinical Trials 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 practice.

6.2 Postmarketing Experience

The following adverse reactions have been reported during use of SOLOSEC and other 2 g formulations of secnidazole outside of the United States. 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.

7.1 Oral Contraceptives

There was no clinically significant drug interaction between secnidazole and the combination oral contraceptive, ethinyl estradiol plus norethindrone [see Clinical Pharmacology (12.3)]. SOLOSEC can be co-administered with combination oral contraceptives (e.g., ethinyl estradiol plus norethindrone).

7.2 Alcohol

Alcoholic beverages and preparations containing ethanol or propylene glycol should be avoided during SOLOSEC therapy and for 2 days after treatment is stopped.

Nausea, vomiting, diarrhea, abdominal pain, dizziness, and headache have been reported when SOLOSEC was taken concomitantly with alcohol [see Dosage and Administration (2.3), Adverse Reactions (6.2) and Clinical Pharmacology (12.3)].

8.1 Pregnancy

8.2 Lactation

8.4 Pediatric Use

The safety and effectiveness of SOLOSEC for the treatment of bacterial vaginosis have been established in pediatric patients aged 12 to 17 years old. Use of SOLOSEC in this age group is supported by evidence from a multicenter, open-label safety study in 40 pediatric female patients with bacterial vaginosis [see Adverse Reactions (6.1)] and evidence from adequate and well-controlled studies in adult women [see Clinical Studies (14.1)].

The safety and effectiveness of SOLOSEC for the treatment of trichomoniasis have been established in pediatric patients aged 12 to 17 years old. Use of SOLOSEC in this group is based on the extrapolation of clinical trial data from adult women with trichomoniasis, four open-label trials in males with trichomoniasis, and an open-label safety study in pediatric female patients with bacterial vaginosis [see Adverse Reactions (6.1) and Clinical Studies (14.2)].The safety and effectiveness of SOLOSEC in pediatric patients below the age of 12 years have not been established.

8.5 Geriatric Use

Clinical studies with secnidazole did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects.

12.1 Mechanism of Action

SOLOSEC is a nitroimidazole antimicrobial drug [see Microbiology (12.4)].

12.2 Pharmacodynamics

Secnidazole exposure-response relationships and the time course of pharmacodynamic response are unknown.

12.3 Pharmacokinetics

A single oral dose of 2 g of SOLOSEC in healthy adult female subjects, following an overnight fast and admixed with (4 oz) of applesauce, resulted in a mean (SD) secnidazole peak plasma concentration (Cmax) of 45.4 (7.64) mcg/mL and mean (SD) systemic exposure (AUC0-inf) of 1331.6 (230.16) mcg∙hr/mL. Median (range) time to peak concentration (Tmax) was 4.0 (3.0-4.0) hours. Following administration of the 2 g dose, mean secnidazole plasma concentrations decreased to 22.1 mcg/mL at 24 hours, 9.2 mcg/mL at 48 hours, 3.8 mcg/mL at 72 hours, and 1.4 mcg/mL at 96 hours.

12.4 MICROBIOLOGY

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

14.1 Bacterial Vaginosis

Two randomized placebo-controlled clinical trials (Trial 1 and Trial 2) with similar designs were conducted to evaluate the efficacy of SOLOSEC 2 gram for the treatment of bacterial vaginosis. A diagnosis of bacterial vaginosis was defined as all of (a) the presence of an off-white (milky or gray), thin, homogeneous vaginal discharge; (b) a vaginal pH ≥ 4.7; (c) the presence of Clue cells ≥ 20% of the total epithelial cells on a microscopic examination of the vaginal saline wet mount; (d) a positive "whiff" test (detection of amine odor on addition of 10% KOH solution to a sample of the vaginal discharge); and (e) a Nugent score ≥ 4.

Trial 1 enrolled 144 non-pregnant female patients aged 19 to 54 years and Trial 2 enrolled 189 non-pregnant females aged 18 to 54 years. Black or African American subjects in both trials were 54%. Efficacy was assessed by clinical outcome evaluated 21 to 30 days following a single dose of SOLOSEC. A clinical responder was defined as "normal" vaginal discharge, negative "whiff" test, and clue cells <20%. Additional endpoints included Nugent score cure (Nugent score of 0-3) and therapeutic outcome. A therapeutic responder was defined as a clinical responder with a Nugent score cure. In Trial 2, the endpoints were also assessed at Day 7-14.

In both trials, a statistically significantly greater percentage of patients experienced clinical response, Nugent score cure, and therapeutic response at 21 to 30 days following a single dose of SOLOSEC compared to placebo. Statistically significant results for the endpoints were also achieved at Day 7-14 in Trial 2.

The percentage of patients with clinical response was also consistently higher in both trials in the SOLOSEC arm compared to placebo among all subsets of patients: number of prior episodes of bacterial vaginosis (≤ 3 episodes and ≥ 4 episodes) in past 12 months, baseline Nugent score (score 4-6 and score 7-10), and race (Black/African American and White). Tables 3 and 4 describe the efficacy of SOLOSEC in the treatment of bacterial vaginosis.

14.2 Trichomoniasis

The efficacy of a single 2-gram oral dose of SOLOSEC for the treatment of trichomoniasis was evaluated in a multi-center, prospective, randomized, placebo-controlled, delayed treatment, double-blind, trial (Trial 5, NCT03935217). A total of 147 female patients from the United States aged 15 to 65 years were enrolled and randomized 1:1 to receive either SOLOSEC or placebo. The modified intent-to-treat (mITT) population included all randomized patients who were culture positive for T. vaginalis and negative for other sexually transmitted infections. Of the 131 female patients in the mITT population, the median age was 36 years, and 90.8% were African American. Baseline clinical symptoms of vaginal itching, discharge, or odor were reported in 111 (84.7%) patients. Following initial dosing, the test of cure (TOC) visit occurred 6 to 12 days later. At the TOC visit, patients received the opposite treatment (placebo patients received SOLOSEC and vice versa) with a return visit 7 to 12 days later.

Results for microbiological cure, defined as testing negative for T. vaginalis, for the mITT population are presented in Table 5. The microbiological cure rate at the TOC visit was significantly higher in the SOLOSEC treatment group compared to the placebo group.

The single oral 2 g secnidazole dose was also assessed in four open-label trials in males (one comparative study with metronidazole and ornidazole in males only1 and three single-arm studies in males and females2,3,4). Parasitological evaluation was performed both pre- and post-treatment and reported cure rates ranged from 91.7% (165/180) to 100% (30/30) at time points ranging from 2 to 20 days (n=437, 211 males and 226 females). In addition, the natural history of trichomoniasis in men was evaluated in one study.5 The spontaneous resolution during a mean follow-up of 16 ± 12 days was noted in 36% (5/14) (95% CI: 12.8%, 64.9%) of untreated men.

Store at 20°C to 25°C (68°F to 77°F); excursions permitted to 15°C to 30°C (59°F to 86°F) [See USP Controlled Room temperature].

Administration Instructions

Instruct the patient:

• To sprinkle the entire contents of the packet of SOLOSEC onto applesauce, yogurt or pudding and take all the mixture within 30 minutes without chewing or crunching the granules.
• That after consuming the mixture, they may take a glass of water to aid in swallowing.
• That SOLOSEC is not intended to be dissolved in any liquid.

Advise the patient that SOLOSEC may be taken without regard to the timing of meals.

Vulvovaginal Candidiasis

Advise the patient that use of SOLOSEC may result in vulvovaginal candidiasis that may require treatment with an antifungal agent. [see Warnings and Precautions (5.1)]

Alcohol

Advise patients to avoid consumption of alcoholic beverages and preparations containing ethanol or propylene glycol during SOLOSEC therapy and for 2 days afterward because nausea, vomiting, diarrhea, abdominal pain, dizziness, and headache may occur [see Dosage and Administration (2.3), Adverse Reactions (6.2), Drug Interactions (7.2), and Clinical Pharmacology (12.3)].

Lactation

Advise women not to breastfeed during treatment with SOLOSEC and to discontinue breastfeeding for 96 hours following the administration of SOLOSEC. Also, advise a nursing mother that she may choose to pump and discard her milk for 96 hours after administration of SOLOSEC and feed her infant stored human milk or formula [see Use in Specific Populations (8.2)].

Drug Resistance

Patients should be counseled that antibacterial drugs including SOLOSEC should only be used to treat bacterial infections. They do not treat viral infections (e.g., the common cold). When SOLOSEC is prescribed to treat a bacterial infection, patients should be told that although it is common to feel better early in the course of therapy, the medication should be taken exactly as directed. Skipping doses or not completing the full course of therapy may (1) decrease the effectiveness of the immediate treatment and (2) increase the likelihood that bacteria will develop resistance and will not be treatable by SOLOSEC or other antibacterial drugs in the future.