Baclofen USP is a muscle relaxant and antispastic, available as 10 mg and 20 mg tablets for oral administration. Its chemical name is 4-amino-3-(4-chlorophenyl)-butanoic acid.

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 structural formula is represented below:

C₁₀H₁₂C_lNO₂             M.W. 213.66

Baclofen Tablets USP 10 mg and 20 mg contain the following inactive ingredients: magnesium stearate, microcrystalline cellulose, povidone and starch (corn).

Baclofen is useful for the alleviation of signs and symptoms of spasticity resulting from multiple sclerosis, particularly for the relief of flexor spasms and concomitant pain, clonus, and muscular rigidity.

Patients should have reversible spasticity so that baclofen treatment will aid in restoring residual function.

Baclofen may also be of some value in patients with spinal cord injuries and other spinal cord diseases.

Baclofen is not indicated in the treatment of skeletal muscle spasm resulting from rheumatic disorders.

The efficacy of baclofen in stroke, cerebral palsy, and Parkinson’s disease has not been established and, therefore, it is not recommended for these conditions.

The determination of optimal dosage requires individual titration. Start therapy at a low dosage and increase gradually until optimum effect is achieved (usually between 40-80 mg daily).

The following dosage titration schedule is suggested:

5 mg t.i.d. for 3 days

10 mg t.i.d. for 3 days

15 mg t.i.d. for 3 days

20 mg t.i.d. for 3 days

Thereafter additional increases may be necessary but the total daily dose should not exceed a maximum of 80 mg daily (20 mg q.i.d.).

The lowest dose compatible with an optimal response is recommended. If benefits are not evident after a reasonable trial period, patients should be slowly withdrawn from the drug (see WARNINGS, Abrupt Drug Withdrawal).

Baclofen Tablets USP 10 mg are scored, round, white tablets imprinted DAN 5730 and 10 supplied in bottles of 100 and 500.

Baclofen Tablets USP 20 mg are scored, round, white tablets imprinted DAN 5731 and 20 supplied in bottles of 100 and 500.

Dispense in a tight container with a child-resistant closure.

Store at controlled room temperature 15°-30°C (59°-86°F).

Watson Laboratories, Inc. Corona, CA 92880 USA. Revised: January 2004. FDA rev date:

The most common is transient drowsiness (10-63%). 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 are dizziness (5-15%), weakness (5-15%) and fatigue (2-4%). Others reported:

Neuropsychiatric: Confusion (1-11%), headache (4-8%), insomnia (2-7%); and, rarely, 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: Hypotension (0-9%). Rare instances of dyspnea, palpitation, chest pain, syncope.

Gastrointestinal: Nausea (4-12%), constipation (2-6%); and, rarely, dry mouth, anorexia, taste disorder, abdominal pain, vomiting, diarrhea, and positive test for occult blood in stool.

Genitourinary: Urinary frequency (2-6%); and, rarely, enuresis, urinary retention, dysuria, impotence, inability to ejaculate, nocturia, hematuria.

Other: Instances of rash, pruritus, ankle edema, excessive perspiration, weight gain, nasal congestion.

Some of the CNS and genitourinary symptoms may be related to the underlying disease rather than to drug therapy. The following laboratory tests have been found to be abnormal in a few patients receiving baclofen: increased SGOT, elevated alkaline phosphatase, and elevation of blood sugar.

No information provided.

Abrupt Drug Withdrawal: Hallucinations and seizures have occurred on abrupt withdrawal of baclofen. Therefore, except for serious adverse reactions, the dose should be reduced slowly when the drug is discontinued.

Impaired Renal Function: Because baclofen is primarily excreted unchanged through the kidneys, it should be given with caution, and it may be necessary to reduce the dosage.

Stroke: Baclofen has not significantly benefitted patients with stroke. These patients have also shown poor tolerability to the drug.

Pregnancy: Baclofen has been shown to increase the incidence of omphaloceles (ventral hernias) in fetuses of rats given approximately 13 times the maximum dose recommended for human use, at a dose which caused significant reductions in food intake and weight gain in dams. This abnormality was not seen in mice or rabbits. There was also an increased incidence of incomplete sternebral ossification in fetuses of rats given approximately 13 times the maximum recommended human dose, and an increased incidence of unossified phalangeal nuclei of forelimbs and hindlimbs in fetuses of rabbits given approximately 7 times the maximum recommended human dose. In mice, no teratogenic effects were observed, although reductions in mean fetal weight with consequent delays in skeletal ossification were present when dams were given 17 or 34 times the human daily dose. There are no studies in pregnant women. Baclofen should be used during pregnancy only if the benefit clearly justifies the potential risk to the fetus.

Safe use of baclofen in pediatric patients under age 12 has not been established, and it is, therefore, not recommended for use in pediatric patients.

Because of the possibility of sedation, patients should be cautioned regarding the operation of automobiles or other dangerous machinery, and activities made hazardous by decreased alertness. Patients should also be cautioned that the central nervous system effects of baclofen may be additive to those of alcohol and other CNS depressants.

Baclofen should be used with caution where spasticity is utilized to sustain upright posture and balance in locomotion or whenever spasticity is utilized to obtain increased function.

In patients with epilepsy, the clinical state and electroencephalogram should be monitored at regular intervals, since deterioration in seizure control and EEG have been reported occasionally in patients taking baclofen.

It is not known whether this drug is excreted in human milk. As a general rule, nursing should not be undertaken while a patient is on a drug since many drugs are excreted in human milk.

A dose-related increase in incidence of ovarian cysts and a less marked increase in enlarged and/or hemorrhagic adrenal glands was observed in female rats treated chronically with baclofen.

Ovarian cysts have been found by palpation in about 4% of the multiple sclerosis patients that were treated with baclofen for up to one year. In most cases these cysts disappeared spontaneously while patients continued to receive the drug. Ovarian cysts are estimated to occur spontaneously in approximately 1% to 5% of the normal female population.

Signs and symptoms: Vomiting, muscular hypotonia, drowsiness, accommodation disorders, coma, respiratory depression, and seizures.

Treatment: In the alert patient, empty the stomach promptly by induced emesis followed by lavage. In the obtunded patient, secure the airway with a cuffed endotracheal tube before beginning lavage (do not induce emesis). Maintain adequate respiratory exchange, do not use respiratory stimulants.

Hypersensitivity to baclofen.

ACTIONS

The precise mechanism of action of baclofen is not fully known. Baclofen is capable of inhibiting both monosynaptic and polysynaptic reflexes at the spinal level, possibly by hyperpolarization of afferent terminals, although actions at supraspinal sites may also occur and contribute to its clinical effect. Although baclofen is an analog of the putative inhibitory neurotransmitter gamma-aminobutyric acid (GABA), there is no conclusive evidence that actions on GABA systems are involved in the production of its clinical effects. In studies with animals, baclofen has been shown to have general CNS depressant properties as indicated by the production of sedation with tolerance, somnolence, ataxia, and respiratory and cardiovascular depression. Baclofen is rapidly and extensively absorbed and eliminated. Absorption may be dose-dependent, being reduced with increasing doses. Baclofen is excreted primarily by the kidney in unchanged form and there is relatively large intersubject variation in absorption and/or elimination.

No information provided. Please refer to the WARNINGS and PRECAUTIONS sections.

IMPORTANT NOTE: This is a summary and does not contain all possible information about this product. For complete information about this product or your specific health needs, ask your health care professional. Always seek the advice of your health care professional if you have any questions about this product or your medical condition. This information is not intended as individual medical advice and does not substitute for the knowledge and judgment of your health care professional. This information does not contain any assurances that this product is safe, effective, or appropriate for you.

BACLOFEN - ORAL

(BACK-low-fen)

COMMON BRAND NAME(S): Lioresal

USES: Baclofen is used to treat muscle tightness and cramping (spasms) caused by certain conditions such as multiple sclerosis and spinal cord injury/disease. It works by relaxing the muscles. Decreasing spasms helps reduce pain and stiffness, improves your ability to move around, and lets you do more of your daily activities.

HOW TO USE: Take this medication by mouth, usually 3 times a day or as directed by your doctor. In general, your doctor may slowly increase your dose to lower your chance of side effects until the right dose for you is determined.

Do not increase your dose or take it more often than prescribed. Do not suddenly stop taking this drug without your doctor's approval. If you suddenly stop taking this drug, withdrawal reactions may occur. Such reactions can include seizures or hearing/seeing things that are not there (hallucinations). Report any such reactions to your doctor immediately. When stopping extended, regular treatment with this drug, gradually reducing the dosage as directed will help prevent withdrawal reactions. Consult your doctor or pharmacist for more details.

Use this medication regularly in order to get the most benefit from it. Remember to take it at the same times each day. Dosage is based on your medical condition and response to therapy.

It may take 1-2 months or longer to get the full benefit from this medication. Inform your doctor if your condition does not improve or if it worsens.

SIDE EFFECTS: Drowsiness, dizziness, weakness, tiredness, headache, trouble sleeping, nausea, or constipation may occur. If any of these effects persist or worsen, notify your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor immediately if any of these unlikely but serious side effects occur: mental/mood changes (e.g., confusion, depression, hallucinations), hearing/vision changes, seizures, fast/pounding heartbeat, fainting, black/bloody stools.

Seek immediate medical attention if any of these rare but very serious side effects occur: chest pain, shortness of breath.

A very serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction may include: rash, itching, swelling, severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

Contact your doctor for medical advice about side effects. The following numbers do not provide medical advice, but in the US you may report side effects to the Food and Drug Administration (FDA) at 1-800-FDA-1088. In Canada, you may call Health Canada at 1-866-234-2345.

PRECAUTIONS: Before taking baclofen, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney problems, seizure disorder, mental/mood disorders, brain disorders (e.g., stroke).

Before having surgery, tell your doctor or dentist that you are using this medication.

This drug may make you dizzy or drowsy; use caution engaging in activities requiring alertness such as driving or using machinery. Limit alcoholic beverages.

Kidney function declines as you grow older. This medication is removed by the kidneys. Therefore, the elderly may be more sensitive to the side effects of this drug, especially mental/mood changes.

This medication should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor.

This drug passes into breast milk. Consult your doctor before breast-feeding.

DRUG INTERACTIONS: Your healthcare professionals (e.g., doctor or pharmacist) may already be aware of any possible drug interactions and may be monitoring you for it. Do not start, stop or change the dosage of any medicine before checking with them first.

Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use.

Tell your doctor or pharmacist if you also take drugs that cause drowsiness such as: certain antihistamines (e.g., diphenhydramine), anti-seizure drugs (e.g., carbamazepine), medicine for sleep or anxiety (e.g., alprazolam, diazepam, zolpidem), other muscle relaxants, narcotic pain relievers (e.g., codeine), psychiatric medicines (e.g., chlorpromazine, risperidone, trazodone).

Check the labels on all your medicines (e.g., cough-and-cold products) because they may contain drowsiness-causing ingredients. Ask your pharmacist about the safe use of those products.

Also report the use of drugs which might increase seizure risk (decrease seizure threshold) when combined with baclofen such as isoniazid (INH), phenothiazines (e.g., thioridazine), theophylline, or tricyclic antidepressants (e.g., amitriptyline), among others. Consult your doctor or pharmacist for details.

This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist.

OVERDOSE: If overdose is suspected, contact your local poison control center or emergency room immediately. US residents can call the US national poison hotline at 1-800-222-1222. Canadian residents should call their local poison control center directly. Symptoms of overdose may include severe muscle weakness, vomiting, severe drowsiness, seizures, slowed breathing, loss of consciousness.

NOTES: Do not share this medication with others.

MISSED DOSE: If you miss a dose, take it as soon as you remember if it is within about 1 hour of that scheduled dose. If you do not remember until later, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.

STORAGE: Store at room temperature between 59-86 degrees F (15-30 degrees C) away from light and moisture. Do not store in the bathroom. Keep all medicines away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.

MEDICAL ALERT: Your condition can cause complications in a medical emergency. For enrollment information call MedicAlert at 1-800-854-1166 (USA) or 1-800-668-1507 (Canada).

Information last revised July 2008 Copyright(c) 2008 First DataBank, Inc.