Reserpine Levodopa

Amines, prescribed or proprietary Amphetamine and congeners Ephedrine and congeners Levodopa Reserpine T ryptophan... 

Levodopa interacts with many different drugs. When levodopa is used with phenytoin, reserpine, and papaverine, there is a decrease in response to levodopa The risk of a hypertensive crisis increases when levodopa is used with the monoamine oxidase inhibitors (see Chap. 31). Foods high in pyridoxine (vitamin B6) or vitamin B6 preparations reverse the effect of levodopa However, when carbidopa is used with levodopa, pyridoxine has no effect on the action of levodopa hi fact, when levodopa and carbidopa are given together, pyridoxine may be prescribed to decrease the adverse effects associated with levodopa... 

As in AD, knowdedge of the neurotransmitter deficiency underlying PD, in this case dopamine, has been the basis for the development of therapy. Early studies show ed that cerebral dopamine was concentrated in the shiatum and that levodopa, the precursor to dopamine, could reverse the akinetic effects of the dopamine-depleting agent reserpine in experimental animals (Carlsson et al., 1957, 1958). Eventually, the identification of shiatal dopamine depletion as a key neurochemical finding in parkinsonian brains lead to heatment wdth levodopa in humans and to the subsequent advent of compounds that mimic the effects of dopamine or prolong its action (Table 39.2). 

Clinically important, potentially hazardous interactions with antipsychotics, cyclic antidepressants, levodopa, MAO inhibitors, reserpine... 

Segovia G, Mora F, Crossman AR, Brotchie JM (2003) Effects of CBl cannabinoid receptor modulating compounds on the hyperkinesia induced by high-dose levodopa in the reserpine-treated rat model of Parkinson s disease. Mov Disord 18 138-149... 

Furthermore, both methyldopa and reserpine, that essentially interfere with the catecholamine synthesis as well as its storage, exacerbate the Parkinson syndrome and, therefore, antagonize the activity of levodopa. The pharmacological profile of levodopa actually synergized by antimuscarinics. 

The effects of levodopa are opposed by rauwolfia alkaloids such as reserpine. 

Reserpine and other rauwolfia alkaloids deplete the brain of monoamines, including dopamine, thereby reducing their effects. This can lead to parkinsonian-like symptoms, and may oppose the actions of administered levodopa. There are not only sound pharmacological reasons for believing this to be an interaetion of elinieal importance, but a reduction in the antiparkinsonian activity of levodopa has been observed in patients given reserpine. The rauwolfia alkaloids should be avoided in patients with Parkinson s disease, whether or not they are taking levodopa. 

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