5.1 Potentiation of Vascular Insufficiency

Brimonidine topical gel should be used with caution in patients with depression, cerebral or coronary insufficiency, Raynaud’s phenomenon, orthostatic hypotension, thrombangiitis obliterans, scleroderma, or Sjögren’s syndrome.

5.2 Severe Cardiovascular Disease

Alpha-2 adrenergic agonists can lower blood pressure. Brimonidine topical gel should be used with caution in patients with severe or unstable or uncontrolled cardiovascular disease.

5.3 Serious Adverse Reactions Following Ingestion of Brimonidine Topical Gel

Two young children of a subject in a clinical trial experienced serious adverse reactions following accidental ingestion of brimonidine topical gel. Adverse reactions experienced by one or both children included lethargy, respiratory distress with apneic episodes (requiring intubation), sinus bradycardia, confusion, psychomotor hyperactivity, and diaphoresis. Both children were hospitalized overnight and discharged the following day without sequelae.

Keep brimonidine topical gel out of the reach of children.

5.4 Systemic Adverse Reactions of Alpha 2-adrenergic agonists

Postmarketing cases of bradycardia, hypotension (including orthostatic hypotension) and dizziness have been reported. Some cases required hospitalization. Some cases involved application of brimonidine topical gel in unapproved dosing regimens and for unapproved indications, including the application of brimonidine topical gel following laser procedures.

Avoid applying brimonidine topical gel to irritated skin or open wounds.

5.5 Local Vasomotor Adverse Reactions

Erythema

Some subjects in the clinical trials discontinued use of brimonidine topical gel because of erythema. Some subjects in the clinical trials reported a rebound phenomenon, where erythema was reported to return worse compared to the severity at baseline. Erythema appeared to resolve after discontinuation of brimonidine topical gel [see Adverse Reactions (6.1)].

The treatment effect of brimonidine topical gel may begin to diminish hours after application.

From postmarketing reports, some patients have experienced erythema involving areas of the face that were previously not affected by erythema and in areas (e.g., neck and chest) outside of the treatment sites.

Flushing

Some subjects in the clinical trials discontinued use of brimonidine topical gel because of flushing.

Intermittent flushing occurred in some subjects treated with brimonidine topical gel in the clinical trials. The onset of flushing relative to application of brimonidine topical gel varied, ranging from approximately 30 minutes to several hours [see Adverse Reactions (6.1)]. Flushing appeared to resolve after discontinuation of brimonidine topical gel.

From postmarketing reports, some patients have experienced increased frequency of flushing and/or increased depth of erythema with the flushing. Additionally, some patients reported new onset of flushing.

Pallor and Excessive Whitening

From postmarketing reports, some patients have experienced pallor or excessive whitening at or outside the application site following treatment with brimonidine topical gel.

5.6 Hypersensitivity

Allergic contact dermatitis was reported in the clinical trials for brimonidine topical gel [see Adverse Reactions (6.1)].

Events reported post marketing with the use of brimonidine topical gel include angioedema, throat tightening, tongue swelling, and urticarial [see Adverse Reactions (6.2)]. Institute appropriate therapy and discontinue brimonidine topical gel, if clinically significant hypersensitivity reaction occurs.

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.

During clinical trials, 1210 subjects were exposed to brimonidine topical gel. A total of 833 subjects were treated for persistent (nontransient) erythema associated with rosacea, and 330 of those were treated once daily for 29 days in vehicle-controlled trials.

Adverse reactions that occurred in at least 1% of subjects treated with brimonidine topical gel once daily for 29 days and for which the rate for brimonidine topical gel exceeded the rate for vehicle are presented in Table 1.

Table 1 - Adverse Reactions Reported in Clinical Trials by at Least 1% of Subjects Treated for 29 Days

Open-label, Long-term Study

An open-label study of brimonidine topical gel when applied once daily for up to one year was conducted in subjects with persistent (nontransient) facial erythema of rosacea. Subjects were allowed to use other rosacea therapies. A total of 276 subjects applied brimonidine topical gel for at least one year. The most common adverse events (≥ 4% of subjects) for the entire study were flushing (10%), erythema (8%), rosacea (5%), nasopharyngitis (5%), skin burning sensation (4%), increased intraocular pressure (4%), and headache (4%).

Allergic contact dermatitis

Allergic contact dermatitis to brimonidine topical gel was reported in approximately 1% of subjects across the clinical development program. Two subjects underwent patch testing with individual product ingredients. One subject was found to be sensitive to brimonidine tartrate, and one subject was sensitive to phenoxyethanol (a preservative).

6.2 Postmarketing Experience

The following adverse reactions have been identified during post-approval use of brimonidine topical gel. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to estimate their frequency or establish a causal relationship to drug exposure.

Cardiovascular disorders: bradycardia, hypotension (including orthostatic hypotension)

Immune system disorders: angioedema, hypersensitivity, lip swelling, swollen tongue, throat tightness, urticaria

Nervous system disorders: dizziness

Skin and subcutaneous disorders: pallor

7.1 Anti-hypertensives/Cardiac Glycosides

Alpha-2 agonists, as a class, may reduce blood pressure. Caution in using drugs such as beta-blockers, anti-hypertensives and/or cardiac glycosides is advised.

7.2 CNS Depressants

Although specific drug-drug interactions studies have not been conducted with brimonidine topical gel, the possibility of an additive or potentiating effect with CNS depressants (alcohol, barbiturates, opiates, sedatives, or anaesthetics) should be considered.

7.3 Monoamine Oxidase Inhibitors

Monoamine oxidase (MAO) inhibitors may theoretically interfere with the metabolism of brimonidine and potentially result in an increased systemic side-effect such as hypotension. Caution is advised in patients taking MAO inhibitors which can affect the metabolism and uptake of circulating amines.

8.1 Pregnancy

Pregnancy Category B.

There are no adequate and well-controlled studies of brimonidine topical gel in pregnant women. In animal studies, brimonidine crossed the placenta and entered into the fetal circulation to a limited extent. Brimonidine topical gel should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Brimonidine tartrate was not teratogenic when given at oral doses up to 2.5 mg/kg/day in pregnant rats during gestation days 6 through 15 and 5 mg/kg/day in pregnant rabbits during gestation days 6 through 18.

8.3 Nursing Mothers

It is not known whether brimonidine tartrate is excreted in human milk, although in animal studies, brimonidine tartrate has been shown to be excreted in breast milk. Because of the potential for serious adverse reactions from brimonidine topical gel in nursing infants, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.

8.4 Pediatric Use

Keep brimonidine topical gel out of reach of children. Serious adverse reactions were experienced by two children of a subject in a clinical trial who accidentally ingested brimonidine topical gel [see Warnings and Precautions (5.3)].

Safety and effectiveness in pediatric patients have not been established.

8.5 Geriatric Use

One hundred and five subjects aged 65 and older were included in clinical trials with brimonidine topical gel. No overall differences in safety or effectiveness were observed between subjects ≥ 65 years of age and younger adult subjects. Clinical studies of brimonidine topical gel 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

Brimonidine is a relatively selective alpha-2 adrenergic agonist. Topical application of brimonidine topical gel may reduce erythema through direct vasoconstriction.

12.3 Pharmacokinetics

Absorption

The absorption of brimonidine from brimonidine topical gel was evaluated in a clinical trial in 24 adult subjects with facial erythema associated with rosacea. All enrolled subjects received once daily topical application of brimonidine topical gel 1 gram to the entire face for 29 days. Pharmacokinetic assessments were performed on Day 1, Day 15, and Day 29. The mean plasma maximum concentration (Cmax) and area under the concentration-time curve (AUC) were highest on Day 15, with Cmax and AUC values (± standard deviation) of 46 ± 62 pg/mL and 417 ± 264 pg.hr/mL, respectively. The systemic drug exposure was slightly lower on Day 29 indicating no further drug accumulation.

Metabolism

Brimonidine is extensively metabolized by the liver.

Excretion

Urinary excretion is the major route of elimination of brimonidine and its metabolites.

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

Carcinogenesis

In a 21-month oral (diet) mouse carcinogenicity study and a 24-month oral (diet) rat carcinogenicity study, no drug-related neoplasms were observed in mice at oral doses of brimonidine tartrate up to 2.5 mg/kg/day or in rats at oral doses of brimonidine tartrate up to 1 mg/kg/day.

In a dermal rat carcinogenicity study with brimonidine topical gel, brimonidine tartrate was administered to Wistar rats at topical doses of 0.9 (0.03% gel), 1.8 (0.06% gel), and 5.4 mg/kg/day (0.18% gel) in males and 5.4 (0.18% gel), 30 (1% gel) during Days 1-343/10.8 (0.36% gel) thereafter, and 60 (2% gel) during Days 1-343/21.6 mg/kg/day (0.72% gel) thereafter in females once daily for 24 months. No drug-related neoplasms were observed in this study.

In a 12-month dermal photo-carcinogenicity study, topical doses of 0% (brimonidine topical gel vehicle), 0.18%, 1% and 2% brimonidine tartrate gel were administered to hairless albino mice once daily, five days per week, with concurrent exposure to simulated sunlight. No drug-related adverse effects were observed in this study. The results of this study suggest that topical treatment with brimonidine topical gel would not enhance photo-carcinogenesis.

Mutagenesis

Brimonidine tartrate was not mutagenic or clastogenic in a series of in vitro and in vivo studies, including the Ames test, a chromosomal aberration assay in Chinese Hamster Ovary (CHO) cells, and three studies in CD1 mice (a host-mediated assay, a cytogenetic study, and a dominant lethal assay).

Impairment of Fertility

Reproduction and fertility studies in rats with brimonidine tartrate demonstrated no adverse effects on male or female fertility at oral doses up to 1 mg/kg/day.