Source: Medicines & Healthcare Products Regulatory Agency (GB) Revision Year: 2019 Publisher: Generics [UK] Ltd t/a Mylan, Station Close, Potters Bar, Herts, EN6 1TL
Hypersensitivity to the active substance or to any of the excipients listed in section 6.1.
Peptic ulceration.
Porphyria, history of alcoholism, hypertension, psychotic disorders, schizophrenia, depressive or manic disorders, confusional states or Parkinson’s disease may be exacerbated by treatment with baclofen. Patients suffering from these conditions should therefore be treated cautiously and kept under close surveillance.
Suicide and suicide-related events have been reported in patients treated with baclofen. In most cases, the patients had additional risk factors associated with an increased risk of suicide including alcohol use disorder, depression and/or a history of previous suicide attempts. Close supervision of patients with additional risk factors for suicide should accompany drug therapy. Patients (and caregivers of patients) should be alerted about the need to monitor for clinical worsening, suicidal behaviour or thoughts or unusual changes in behaviour and to seek medical advice immediately if these symptoms present.
Cases of misuse, abuse and dependence have been reported with baclofen. Caution should be exercised in patients with a history of substance abuse and the patient should be monitored for symptoms of baclofen misuse, abuse or dependence e.g. dose escalation, drug-seeking behaviour, development of tolerance.
Baclofen may also exacerbate epileptic manifestations but can be employed provided appropriate supervision and adequate anticonvulsive therapy are maintained.
Baclofen should be used with extreme care in patients already receiving antihypertensive therapy (see section 4.5).
Baclofen should be used with caution in patients suffering from cerebrovascular accidents or from respiratory or hepatic impairment.
Signs of overdose have been observed in patients with renal impairment taking baclofen at doses of more than 5 mg per day. Baclofen should be used with caution in patients with renal insufficiency and should only be administered to patients with end-stage renal failure (CKD stage 5, GFR < 15 ml/min) only if the expected benefit outweighs the potential risk (see section 4.2 Posology and method of administration). Neurological signs and symptoms of overdose including clinical manifestations of toxic encephalopathy (e.g. confusion, disorientation, somnolence and depressed level of consciousness) have been observed in patients with renal impairment taking oral baclofen at doses of more than 5mg per day. Patients with impaired renal function should be closely monitored for prompt diagnosis of early symptoms of toxicity.
Cases of baclofen toxicity have been reported in patients with acute renal failure (see section 4.9).
Particular caution is required when combining baclofen with drugs or medicinal products that can significantly affect renal function. Renal function should be closely monitored and baclofen daily dosage adjusted accordingly to prevent baclofen toxicity.
Besides discontinuing treatment, unscheduled haemodialysis might be considered as a treatment alternative in patients with severe baclofen toxicity. Haemodialysis effectively removes baclofen from the body, alleviates clinical symptoms of overdose and shortens the recovery time in these patients.
Under treatment with baclofen, neurogenic disturbances affecting emptying of the bladder may show an improvement. In patients with pre-existing sphincter hypertonia, acute retention of urine may occur; the drug should be used with caution in such patients.
Treatment should always, (unless serious adverse effects occur), be gradually discontinued by successively reducing the dosage over a period of about 1-2 weeks. Anxiety and confusional state, delirium, hallucination, psychotic disorder, mania or paranoia, convulsion (status epilepticus), dyskinesia, tachycardia, hyperthermia, rhabdomyolysis and temporary aggravation of spasticity as a rebound phenomenon have been reportedwith abrupt withdrawal of baclofen, especially after long term medication.
Neonatal convulsions have been reported after intrauterine exposure to oral baclofen (see section 4.6).
Treatment should always (unless serious adverse effects occur) therefore be gradually discontinued by successively reducing the dosage over a period of about 1-2 weeks.
In rare instances, elevated aspartate aminotransferase, alkaline phosphatase and glucose levels in serum have been recorded. Appropriate laboratory tests should be performed in patients with liver diseases or diabetes mellitus in order to ensure that no drug induced changes in these underlying diseases have occurred.
Baclofen should be used with caution when spasticity is needed to sustain upright posture and balance in locomotion (see section 4.2).
There is very limited clinical data on the use of baclofen in children under the age of one year. Use in this patient population should be based on the physician’s consideration of individual benefit and risk of therapy.
Baclofen Tablets contain lactose. Patients with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption should not take this medicine.
This medicinal product contains less than 1 mmol sodium (23 mg) per tablet, that is to say essentially ‘sodium-free’.
Increased sedation may occur when baclofen is taken concomitantly with other drugs causing CNS depression including other muscle relaxants (such as tizanidine), with synthetic opiates or with alcohol (see section 4.7).
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 muscles weakness.
Pre-treatment with baclofen may prolong the duration of fentanyl induced anaesthesia.
Concomitant use of oral baclofen and lithium resulted in aggravated hyperkinetic symptoms. Thus, caution should be exercised when baclofen is used concomitantly with lithium.
During concomitant treatment with tricyclic antidepressants, the effect of baclofen may be potentiated, resulting in pronounced muscular hypotonia.
Since concomitant treatment with baclofen and anti-hypertensives is likely to increase the fall in blood pressure, the dosage of anti-hypertensive medication should be adjusted accordingly.
Drugs or medicinal products that can significantly affect renal function may reduce baclofen excretion leading to toxic effects (see Section 4.4).
In patients with Parkinson’s disease receiving treatment with baclofen and levodopa (alone or in combination with DDC inhibitor, carbidopa), there have been reports of mental confusion, hallucinations, nausea and agitation. Worsening of the symptoms of Parkinsonism has also been reported. Hence, caution should be exercised during concomitant administration of baclofen and levodopa/carbidopa.
During pregnancy, especially in the first 3 months, baclofen should only be employed if its use is of vital necessity. The benefits of the treatment for the mother must be carefully weighed against the possible risks for the child. Baclofen crosses the placental barrier.
One case of suspected withdrawal reaction (generalised convulsions) has been reported in a week-old infant whose mother had taken oral baclofen 80 mg daily throughout her pregnancy. The convulsions, which were refractory to standard anticonvulsant treatment, ceased within 30 minutes of giving baclofen to the infant.
In mothers taking baclofen in therapeutic doses, the active substance passes into the breast milk, but in quantities so small that no undesirable effects on the infant are to be expected.
Baclofen may be associated with adverse effects such as dizziness, sedation, somnolence and visual impairment (see section 4.8) which may impair the patient’s reaction. Patients experiencing these adverse reactions should be advised to refrain from driving or operating machinery.
Adverse effects occur mainly at the start of treatment (e.g. sedation, somnolence and nausea), if the dosage is raised too rapidly, if large doses are employed, or in elderly patients. They are often transitory and can be attenuated or eliminated by reducing the dosage; they are seldom severe enough to necessitate withdrawal of the medication.
Should nausea persist following a reduction in dosage, it is recommended that baclofen be ingested with food or a milk beverage.
Lowering of the convulsion threshold and convulsions may occur, particularly in epileptic patients.
In patients with a history of psychiatric illness or with cerebrovascular disorders (e.g. stroke) as well as in elderly patients, adverse reactions may assume a more serious form.
Certain patients have shown increased spasticity as a paradoxical reaction to the medication.
An undesirable degree of muscular hypotonia – making it more difficult for patients to walk or fend for themselves – may occur and can usually be relieved by re-adjusting the dosage (i.e. by reducing the doses given during the day and possibly increasing the evening dose).
Adverse reactions (Table 1) are ranked under the heading of frequency, the most frequent first, using the following convention: very common (≥ 1/10), common (≥ 1/100 to < 1/10), uncommon (≥ 1/1000 to < 1/100), rare (≥ 1/10,000 to < 1/1000), very rare (< 1/10,000) and Not known (frequency cannot be estimated from the available data).
Table 1. Tabulated summary of adverse drug reactions
Very common: sedation, somnolence
Common: Dry mouth, respiratory depression, light-headedness, fatigue, confusional state, dizziness, headache, insomnia, depression, euphoric mood, myalgia, muscular weakness, ataxia, tremor, nystagmus, hallucination, nightmare,
Rare: paraesthesia, dysarthria, dysgeusia
Not known: sleep apnoea syndrome*
Common: accommodation disorder, visual impairment
Common: cardiac output decreased
Not known: bradycardia
Common: hypotension
Very common: nausea
Common: gastrointestinal disorder, retching, vomiting, constipation, diarrhoea
Rare: abdominal pain
Rare: hepatic function abnormal
Common: hyperhidrosis, rash
Not known: urticaria
Common: dysuria, pollakiuria, enuresis
Rare: urinary retention
Rare: erectile dysfunction
Very rare: hypothermia
Not known: drug withdrawal syndrome (see section 4.4)
Not known: blood glucose increased
* Cases of central sleep apnoea syndrome have been observed with baclofen at high doses (≥ 100 mg) in patients who are alcohol dependent.
Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store.
Not applicable.
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