"By Kathleen Doheny
WebMD Health News
Reviewed by Michael W. Smith, MD
Dec. 30, 2013 -- The FDA has rejected the new multiple sclerosis drug Lemtrada, saying the drugmaker didn't show the drug's benefits outweigh some s"...
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 by the kidneys, it should be given with caution and it may be necessary to reduce the dosage in patients with impaired renal function.
Baclofen has not significantly benefited patients with stroke. These patients have also shown poor tolerability to the drug.
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.
Carcinogenesis, Mutagenesis, Impairment of Fertility
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.
Pregnancy Category C. 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 adequate and well-controlled studies in pregnant women. KEMSTRO™ (baclofen) should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when KEMSTRO™ (baclofen) is administered to a nursing woman.
Safety and effectiveness in pediatric patients below the age of 12 have not been established.
Clinical studies of baclofen did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. 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 toxic 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.
Sedating drugs may cause confusion and over-sedation in the elderly; elderly patients generally should be started on low doses of KEMSTRO™ (baclofen) and observed closely.
Last reviewed on RxList: 11/20/2007
This monograph has been modified to include the generic and brand name in many instances.
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