Anesthetics: Anesthetic agents may potentiate the CNS effects of baclofen.
Antidepressants: The concomitant administration of baclofen and tricyclic antidepressants may potentiate the pharmacological effects of baclofen, resulting in pronounced muscular hypotonia. In addition, concomitant use of tricyclic antidepressants can cause sedation, drowsiness and potentiate the effects of pms-BACLOFEN resulting in pronounced muscular hypotonia.
Lithium: Concomitant use of oral baclofen and lithium resulted in aggravated hyperkinetic symptoms. Caution should be exercised when pms-BACLOFEN is used concomitantly with lithium.
MAO Inhibitors: The concurrent use of MAO inhibitors and baclofen may result in increased CNS-depressant effects; therefore, caution is advised and the dosage of one or both agents should be adjusted accordingly.
Antihypertensives: Since combined treatment with baclofen and antihypertensives is likely to increase the fall in blood pressure, the dosage of antihypertensive medication should be adjusted accordingly.
Levodopa/Dopa Decarboxylase (DDC) Inhibitor (Carbidopa): In patients with Parkinson's disease receiving treatment with baclofen and levodopa (alone or in combination with a DDC inhibitor, carbidopa), there have been several reports of mental confusion, hallucinations, headache, nausea and agitation. Worsening of the symptoms of Parkinsonism has also been reported. Hence, caution should be exercised during concomitant administration of pms-BACLOFEN and levodopa/carbidopa.
Antidiabetic Agents: Isolated cases of increased blood glucose concentrations have been reported with baclofen; dosage adjustments of antidiabetic agents (oral and insulin) may therefore be necessary with combined pms-BACLOFEN treatment.
Neuromuscular Blocking Agents: Caution should be exercised when administering pms-BACLOFEN and magnesium sulfate (or other neuromuscular blocking agents), since a synergistic effect may theoretically occur.
Agents reducing renal function: Drugs or medicinal products that can significantly impact renal function (e.g., memantine, NSAIDS) may reduce baclofen excretion leading to toxic effects (see Renal Impairment under Warnings).
Drugs Causing Central Nervous System (CNS) Depression: Increased sedation may occur when baclofen is taken concomitantly with other drugs causing CNS depression, including other muscle relaxants (such as tizanidine), synthetic opiates, hypnotics, anxiolytics or alcohol (see Neurologic: Psychomotor Impairment under Warnings). The risk of respiratory depression is also increased. In addition, hypotension has been reported with concomitant use of morphine and intrathecal baclofen. Careful monitoring of respiratory and cardiovascular functions is essential, especially in patients with cardiopulmonary disease and respiratory muscle weakness.
Lactation: Baclofen is excreted in human milk. As a general rule, nursing should not be undertaken while a patient is on a drug.
Infertility: There are no data available on the effect of baclofen on fertility in humans. Baclofen did not impair male or female fertility at non-maternally toxic doses in rats (see Pharmacology: Toxicology: Teratology and Reproduction Studies under Actions).