Baclofen

Dosage and Administration ( 2.3 ) 4/2024

1 INDICATIONS AND USAGE Baclofen oral suspension is indicated for the treatment of spasticity resulting from multiple sclerosis, particularly for the relief of flexor spasms and concomitant pain, clonus, and muscular rigidity. Baclofen oral suspension may also be of some value in patients with spinal cord injuries and other spinal cord diseases. Limitations of Use Baclofen oral suspension is not indicated in the treatment of skeletal muscle spasm resulting from rheumatic disorders. • Baclofen oral suspension is a gamma-aminobutyric acid (GABA-ergic) agonist indicated for the treatment of spasticity resulting from multiple sclerosis, particularly for the relief of flexor spasms and concomitant pain, clonus, and muscular rigidity. ( 1 ) • Baclofen oral suspension may also be of some value in patients with spinal cord injuries and other spinal cord diseases. ( 1 ) Limitations of Use Baclofen oral suspension is not indicated in the treatment of skeletal muscle spasm resulting from rheumatic disorders. ( 1 )

2 DOSAGE AND ADMINISTRATION Baclofen is a concentrated formulation. Verify the dose of the product prior to dispensing. ( 2.1 ) Initiate baclofen with a low dosage, preferably in divided doses, administered orally. Increase gradually based on clinical response and tolerability. ( 2.2 ) The maximum dosage is 80 mg daily (20 mg four times a day). ( 2.2 ) When discontinuing, reduce the dosage slowly. ( 2.3 ) 2.1 Important Information Baclofen is a concentrated formulation. Verify the strength and the dose of the product prior to prescribing, dispensing, and administering. 2.2 Recommended Dosage Initiate baclofen with a low dosage, preferably in divided doses, administered orally. The following gradually increasing dosage regimen is suggested, but should be adjusted based on clinical response and tolerability: 1 mL (5 mg) three times a day for three days 2 mL (10 mg) three times a day for three days 3 mL (15 mg) three times a day for three days 4 mL (20 mg) three times a day for three days Additional increases may be necessary up to the maximum recommended dosage of 80 mg daily [4 mL (20 mg) four times a day]. 2.3 Administration Instructions Shake well baclofen oral suspension before administration. Discard unused portion 2 months after first opening. A calibrated measuring device is recommended to measure and deliver the prescribed dose accurately. A household teaspoon or tablespoon is not an adequate measuring device. Nasogastric Tube Administration Baclofen oral suspension can be administered via a nasogastric (NG) tube at sizes 8 French or larger using the following steps: Ensure the NG feeding tube is flushed with appropriate amount of purified water (15 to 30 mL) prior to administration of baclofen oral suspension. Draw the required dose of baclofen oral suspension in the appropriate oral or enteral syringe and administer the dose via the feeding tube. The medication may remain in the dosing syringe for up to 4 hours prior to administration. If residual drug remains in the dosing syringe, draw up purified water into the syringe, shake gently, and administer through the feeding tube. Flush the feeding tube with at least 25 mL of purified water. 2.4 Discontinuation of Baclofen When discontinuing baclofen, reduce the dosage slowly and avoid abrupt withdrawn from the drug to help minimize the risk of adverse reactions [see Warnings and Precautions ( 5.1 )] .

3 DOSAGE FORMS AND STRENGTHS Oral Suspension: 25 mg per 5 mL (5 mg/mL) baclofen as a concentrated orange to yellow- colored, grape-flavored suspension. Oral Suspension: 25 mg per 5 mL (5 mg/mL) ( 3 )

4 CONTRAINDICATIONS Baclofen oral suspension is contraindicated in patients with hypersensitivity to baclofen. • Hypersensitivity to baclofen ( 4 )

6 ADVERSE REACTIONS The following clinically significant adverse reactions are described elsewhere in the labeling: • Adverse Reactions from Abrupt Withdrawal of baclofen oral suspension [ see Warnings and Precautions ( 5.1 ) ] • Neonatal Withdrawal Symptoms [ see Warnings and Precautions ( 5.2 ) ] • Drowsiness and Sedation [ see Warnings and Precautions ( 5.3 ) ] • Poor Tolerability in Stroke Patients [ see Warnings and Precautions ( 5.4 ) ] • Exacerbation of Psychotic Disorders, Schizophrenia, or Confusional States [ see Warnings and Precautions ( 5.5 ) ] • Exacerbation of Autonomic Dysreflexia [ see Warnings and Precautions ( 5.6 ) ] • Exacerbation of Epilepsy [ see Warnings and Precautions ( 5.7 ) ] • Posture and Balance Effects [ see Warnings and Precautions ( 5.8 ) ] • Ovarian Cysts [ see Warnings and Precautions ( 5.9 ) ] • The most common (up to 15% or more) adverse reactions in patients were drowsiness, dizziness, and weakness. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Slayback Pharma at 1-844-566-2505 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 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. The most common adverse reaction is transient drowsiness. In one controlled study of 175 patients, transient drowsiness was observed in 63% of those receiving baclofen compared to 36% of those in the placebo group. Other common adverse reactions (up to 15%) are dizziness and weakness. Adverse reactions with a frequency of ≥1% are listed in Table 1. Table 1. Common (≥1%) Adverse Reactions in Patients Treated with baclofen for Spasticity ADVERSE REACTION PERCENT Drowsiness 10-63% Dizziness 5-15% Weakness 5-15% Nausea 4-12% Confusion 1-11% Hypotension 0-9% Headache 4-8% Insomnia 2-7% Constipation 2-6% Urinary Frequency 2-6% Fatigue 2-4% The following adverse reactions not included in Table 1, classified by body system, were also reported: Neuropsychiatric: euphoria, excitement, depression, hallucinations, paresthesia, muscle pain, tinnitus, slurred speech, coordination disorder, tremor, rigidity, dystonia, ataxia, blurred vision, nystagmus, strabismus, miosis, mydriasis, diplopia, dysarthria, epileptic seizure Cardiovascular: dyspnea, palpitation, chest pain, syncope Gastrointestinal: dry mouth, anorexia, taste disorder, abdominal pain, vomiting, diarrhea, and positive test for occult blood in stool Genitourinary: enuresis, urinary retention, dysuria, impotence, inability to ejaculate, nocturia, hematuria Other: rash, pruritus, ankle edema, excessive perspiration, weight gain, nasal congestion The following laboratory tests have been found to be abnormal in patients receiving baclofen: increased SGOT, elevated alkaline phosphatase, and elevation of blood sugar.

7 DRUG INTERACTIONS 7.1 CNS Depressants and Alcohol Baclofen oral suspension can cause CNS depression, including drowsiness and sedation, which may be additive when used concomitantly with other CNS depressants or alcohol [see Warnings and Precautions ( 5.3 )].

8 USE IN SPECIFIC POPULATIONS • Pregnancy: Based on animal data, may cause fetal harm. ( 8.1 ) • Because baclofen is excreted unchanged through the kidneys it may be necessary to reduce the dosage in patients with impaired renal function. ( 8.6 ) 8.1 Pregnancy Risk Summary There are no adequate data on the risk of major birth defects, miscarriages, or other maternal adverse outcomes associated with the use of baclofen oral suspension in pregnant women. There are adverse effects on fetal outcomes associated with withdrawal from baclofen after delivery ( see Clinical Considerations ). Oral administration of baclofen to pregnant rats resulted in an increased incidence of fetal structural abnormalities at a dose that was also associated with maternal toxicity. The background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively. Clinical Considerations Fetal/Neonatal Adverse Reactions Baclofen oral suspension may increase the risk of late-onset neonatal withdrawal symptoms [ see Warnings and Precautions ( 5.2 ) ]. Data Animal Data Baclofen given orally has been shown to increase the incidence of omphaloceles (ventral hernias) in fetuses of rats given approximately 13 times on a mg/kg basis, or 3 times on a mg/m 2 basis, the maximum oral dose recommended for human use; this dose also caused reductions in food intake and weight gain in the dams. This abnormality was not seen in mice or rabbits. 8.2 Lactation Risk Summary At recommended oral doses, baclofen is present in human milk. There are no human data on the effects of baclofen on milk production. Withdrawal symptoms can occur in breastfed infants when maternal administration of baclofen oral suspension is stopped, or when breastfeeding is stopped [ see Warnings and Precautions ( 5.2 ) ]. There are no adequate data on other effects of baclofen on the breastfed infant. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for baclofen oral suspension and any potential adverse effects on the breastfed infant from baclofen oral suspension or from the underlying maternal condition. 8.4 Pediatric Use Safety and effectiveness in pediatric patients below the age of 12 have not been established. 8.5 Geriatric Use In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy. This drug is known to be substantially excreted by the kidney, and the risk of adverse reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function [ see Use in Specific Populations ( 8.6 ) ]. 8.6 Renal Impairment Because baclofen is primarily excreted unchanged through the kidneys, baclofen oral suspension should be given with caution to patients with renal impairment, and it may be necessary to reduce the dosage.

12.1 Mechanism of Action The precise mechanism of action of baclofen is not fully understood. Baclofen inhibits both monosynaptic and polysynaptic reflexes at the spinal level, possibly by decreasing excitatory neurotransmitter release from afferent terminals, although actions at supraspinal sites may also occur and contribute to its clinical effect. Baclofen is a structural analog of the inhibitory neurotransmitter gamma- aminobutyric acid (GABA) and may exert its effects by stimulation of the GABA B receptor subtype.

11 DESCRIPTION Baclofen oral suspension is a gamma-aminobutyric acid (GABA-ergic) agonist available as 25 mg per 5 mL (5 mg/mL) suspension for oral administration. Its chemical name is 4-amino-3-(4-chlorophenyl)-butanoic acid, and its structural formula is: Molecular formula is C 10 H 12 C1NO 2 . Molecular Weight is 213.66 g/mol. Baclofen USP is a white to off-white, odorless or practically odorless crystalline powder. It is slightly soluble in water, very slightly soluble in methanol, and insoluble in chloroform. The baclofen oral suspension inactive ingredients are: artificial grape flavor, citric acid anhydrous, D&C yellow No. 10, FD&C red No. 40, hydroxyethyl cellulose, propylene glycol, purified water, simethicone emulsion, sodium benzoate, and sucralose. Structural Formula

10 OVERDOSAGE 10.1 Symptoms of baclofen Overdose With overdose of baclofen, patients may present in coma or with progressive drowsiness, lightheadedness, dizziness, somnolence, accommodation disorders, respiratory depression, seizures, or hypotonia progressing to loss of consciousness. 10.2 Treatment for Overdose The treatment of baclofen overdose includes gastric decontamination, maintaining an adequate airway and respirations.

16 HOW SUPPLIED/STORAGE AND HANDLING 16.1 How Supplied Baclofen oral suspension contains 25 mg per 5 mL (5 mg/mL) baclofen. It is a concentrated orange to yellow-colored, grape-flavored suspension and is supplied in high-density polyethylene (HDPE) bottles with white, polypropylene, child-resistant closures with a foam liner and heat induction layered inner seal. 120 mL, NDC 52536-600-11 300 mL, NDC 52536-600-12 16.2 Storage and Handling Store at 20°C to 25°C (68°F to 77°F); excursions permitted between 15° and 30° (59° and 86° F) (see USP Controlled Room Temperature). Discard unused portion 2 months after first opening.

16.1 How Supplied Baclofen oral suspension contains 25 mg per 5 mL (5 mg/mL) baclofen. It is a concentrated orange to yellow-colored, grape-flavored suspension and is supplied in high-density polyethylene (HDPE) bottles with white, polypropylene, child-resistant closures with a foam liner and heat induction layered inner seal. 120 mL, NDC 52536-600-11 300 mL, NDC 52536-600-12