Side effects
Common side effects of brivaracetam include: constipation, nausea, vomiting, extreme tiredness or low energy. Serious side effects that may be caused include: swelling of the face, throat, tongue, lips, and eyes; difficulty swallowing or breathing; hoarseness, hallucinations (seeing things or hearing sounds that are not there), and delusions (strange thoughts or beliefs that have no basis in reality). An overdose may cause: drowsiness, extreme tiredness, dizziness, difficulty maintaining balance, blurred or double vision, slowed heartbeat, nausea, and feeling anxious.
Synthesis
Two enantioselective routes have been reported, one employing
an enzymatic resolution and the other utilizing (R)-
(-)-epichlorohydrin as a chiral starting material. The route involves an enzymatic resolution,
is the only kilogram-scale route disclosed in the literature to
date and reportedly permits the production of brivaracetam
within the required commercial quality specifications. However,
the authors note that the development of this route for
commercial purposes has been stopped. Commercial
dimethyl n-propylmalonate 108 was first alkylated with tertbutyl-
2-bromoacetate. The resulting product underwent
Krapcho decarboxylation to afford racemic succinate derivative
109 in 94% yield over the two steps. Optimized conditions
for the key enzymatic resolution employed protease C from
Bacillus subtilis type 2 at 30 ??C for 18 h to resolve ester 109 and
provide the acid enantiomer 110. This biocatalytic process
allowed for residual unreacted diester 109 to be washed away
with cyclohexane at pH 9 (adjusted with 0.5 M NaOH), and
the desired acid 110 could be isolated upon lowering the pH
(??1) and extracting with isopropyl acetate (42% yield, 97% ee).
The transformation of acid 110 into propyllactone 111
proceeded in nearly quantitative yield by a three-step sequence:
activation of the acid with ethyl chloroformate, reduction to the
alcohol with sodium borohydride, and cyclization upon acidic
workup with TFA. Exposure of 111 to HBr in acetic acid
followed by esterification of the resulting acid-generated
bromoester 112. Finally, TBAI-catalyzed alkylation of 112
with commercial (S)-2-aminobutanamide (113) in refluxing
isopropyl acetate introduced the n-butylamide moiety while
facilitating lactamization. Addition of MTBE followed by filtration and recrystallization from isopropyl acetate afforded
brivaracetam (IX) in 32% yield and 96% ee.
Drug interactions
Potentially hazardous interactions with other drugs
Antibacterials: concentration reduced by rifampicin.
Antidepressants: antagonism of anticonvulsant effect
(convulsive threshold lowered).
Antimalarials: mefloquine antagonises
anticonvulsant effect.
Antipsychotics: antagonism of anticonvulsant effect
(convulsive threshold lowered).
Orlistat: possibly increased risk of convulsions.
Metabolism
Brivaracetam is mainly metabolised by hydrolysis of the
amide moiety to form the corresponding carboxylic acid
(approximately 60% the elimination), and secondarily by
hydroxylation on the propyl side chain (approximately
30% the elimination). The hydrolysis of the amide moiety
leading to the carboxylic acid metabolite (34% of the
dose in urine) is supported by hepatic and extra-hepatic
amidase. The metabolites are inactive.
Greater than 95% of the dose is excreted in the urine as
brivaracetam and its metabolites.