Interaction with anaesthetics

Trobalt may increase the duration of anesthesia induced by some anaesthetics (for example thiopental sodium; see section 5.1).

Interaction with alcohol

Co-administration of ethanol (1.0 g/kg) with retigabine (200 mg) resulted in an increase in visual blurring in healthy volunteers. It is recommended that patients are advised about the possible effects on vision if they take Trobalt with alcohol.

Laboratory tests

Retigabine has been shown to interfere with clinical laboratory assays of both serum and urine bilirubin, which can result in falsely elevated readings.

4.6 Pregnancy and lactation

 Pregnancy

Risk related to antiepileptic drugs in general

Specialist advice should be given to women who are of childbearing potential. The need for treatment with antiepileptic drugs should be reviewed when a woman is planning to become pregnant. In women being treated for epilepsy, sudden discontinuation of antiepileptic drug therapy should be avoided as this may lead to breakthrough seizures that could have serious consequences for the woman and the unborn child.

The risk of congenital malformations is increased by a factor of 2 to 3 in the offspring of mothers treated with antiepileptic drugs compared with the expected incidence in the general population of approximately 3%. The most frequently reported defects are cleft lip, cardiovascular malformations and neural tube defects. Therapy with multiple antiepileptic drugs is associated with a higher risk of congenital malformations than monotherapy and therefore monotherapy should be used whenever possible.

Risk related to Trobalt

There are no adequate data from the use of retigabine in pregnant women. Animal studies are insufficient with respect to reproductive toxicity because the plasma levels achieved in these studies were less than those reached in humans at recommended doses (see section 5.3). In a developmental study in rats whose mothers were treated with retigabine during pregnancy, there was a delay in auditory startle response development of the offspring (see section 5.3). The clinical significance of this finding is not known.

Trobalt is not recommended during pregnancy and in women of childbearing age, not using contraception.

Breastfeeding
It is unknown whether retigabine is excreted in human breast milk. Animal studies have shown excretion of retagabine and/or its metabolites in breast milk. A decision on whether to continue/discontinue breast-feeding or to continue/discontinue therapy with Trobalt should be made taking into account the benefit of breast-feeding to the child and the benefit of Trobalt therapy to the woman.

Fertility

There were no treatment-related effects of retigabine on fertility in animal studies. However, the plasma levels achieved in these studies were less than those reached in humans at recommended doses (see section 5.3).

The effect of retigabine on human fertility has not been established.

4.7 Effects on ability to drive and use machines

 Adverse reactions such as dizziness, somnolence, diplopia and bl