Somnolence tiagabine

Tiagabine is indicated for the adjunctive treatment of partial seizures and is effective in doses ranging from 16 mg/d to 56 mg/d. Divided doses as often as four times per day are sometimes required. Some patients appear to do well with tiagabine monotherapy, which is generally well tolerated. Minor adverse events are dose-related and include nervousness, dizziness, tremor, difficulty in concentrating, and depression. Excessive confusion, somnolence, or ataxia may require discontinuation. Psychosis occurs rarely. Rash is an uncommon idiosyncratic adverse effect. Laboratory studies are usually normal. 

The effects of tiagabine have been studied in a 4-month, single-blind study in 52 children over the age of 2 years with different syndromes of refractory epilepsy (5). Adverse events, mostly mild to moderate, were reported by 39% of the children during the single-blind placebo period and by 83% of the children during tiagabine treatment. The events predominantly affected the nervous system weakness (19%), nervousness (19%), dizziness (17%), and somnolence (17%) were the most common. One child had hallucinations that responded to dosage reduction. Only three children withdrew because of adverse events. 

Of the 88 patients who entered the double-blind phase, seizure frequency was significantly reduced in 44, and there was an over 50% reduction of partial seizures in 33%. There were adverse events in 77% of the patients during the screening phase and 22% during the double-bhnd phase. The most frequent adverse events were dizziness (32%), somnolence (30%), and weakness (19%). Two patients taking tiagabine withdrew during the double-blind phase because of adverse events. 

In add-on trials, adverse events significantly more common with tiagabine than with placebo were dizziness (30 versus 13%), weakness (24 versus 12%), nervousness (12 versus 3%), tremor (9 versus 3%), depressed mood (5 versus 1%), and emotional labihty (4 versus 1%) (SEDA-19, 73) (SEDA-20, 65) (SEDA-22, 91) (7). Somnolence, amnesia, confusion, difficulty in concentrating, paresthesia, headache, and ataxia can also occur. 

TOXICITY Adverse effects include dizziness, somnolence, and tremor, which are mild to moderate in severity and appear shortly after initiation of therapy. Tiagabine-enhanced effects of synapticaUy released GABA can facilitate spike-and-wave discharges in animal models of absence seizures, suggesting that tiagabine may be contraindicated in patients with generalized absence epilepsy patients with a history of spike-and-wave discharges have been reported to have exacerbations of their EEG abnormalities. 

Side effects are more common with tiagabine than with other adjunct drugs and most often involve the CNS. They include somnolence, headache, dizziness, tremor, abnormal thinking, depression, and psychosis. Furthermore, recent reports have implicated tiagabine in the development of nonconvulsive status epilepticus (88,89). There is an increased risk of seizure in patients being treated for off-label psychiatric indications. Tiagabine may interfere with visual color perception (90). 

Tiagabine 7-9 h 30-70 mg Somnolence, confusion, agitation, dizziness, ataxia, depression, weakness, tremor, seizures. 

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