ICD-10 Specific code G25.0: Essential tremor

Primidone is an anticonvulsant. Although the precise mode of action of primidone is unknown, in common with other anticonvulsants, effects on the neuronal membrane particularly with respect to alteration of ionic fluxes are likely to play a fundamental role.

Propranolol is a competitive antagonist at both beta, and beta₂-adrenoceptor, but has membrane stabilising activity at concentrations exceeding 1-3mg/litre, though such concentrations are rarely achieved during oral therapy. Competitive beta-blockade has been demonstrated in man by a parallel shift to the right in the dose-heart rate response curve to beta-agonists such as isoprenaline.

Tetrabenazine is a synthetic derivative of benzylquinolizine that causes depletion of dopamine and other monoamines in the central nervous system. The precise mechanism by which tetrabenazine exerts its effects is unknown, but is believed to be related to its effect as a reversible depletor of monoamines (such as dopamine, serotonin, norepinephrine, and histamine) from nerve terminals. Neurotransmitter depletion by a single dose of tetrabenazine is reversible and lasts only a few hours.

Tiapride is an atypical neuroleptic which exhibits selectivity in in-vitro studies for D₂ and D₃ dopamine subtype receptors without any affinity for subtype receptors of the principal central neurotransmitters (including serotonin, noradrenaline and histamine).