Levodopa Clonidine

Uses Endogenous depression Action TCA T synaptic CNS levels of serotonin /or norepinephrine Dose Adults. 25 mg PO tid-qid >150 mg/d not OK Elderly. 10-25 mg hs Peds. 6-7 y 10 mg/d 8-11 y 10-20 mg/d >11 y 25-35 mg/d, 4- w/ hepatic insuff Caution [D, +/-] NAG, CV Dz Contra TCA allergy, use w/ MAOI Disp Caps, soln SE Anticholinergic (blurred vision, retention, xerostomia) Interactions T Effects W/ antihistamines, CNS depressants, cimetidine, fluoxetine, OCP, phenothiazine, quinidine, EtOH T effects OF anticoagulants T risk of HTN W/clonidine, levodopa, sympathomimetics T effects W/barbiturates, carbamazepine, rifampin EMS Concurrent use w/ MAOIs have resulted in HTN,... 

Opioids, benzodiazepines, barbiturates, corticosteroids, dopamine agonists (e.g., amantadine, bromocriptine, levodopa, pergolide, pramipexole, ropinirole), H2-receptor antagonists, anticholinergics (e.g., diphenhydramine, trihexylphenidyl), P-adrenergic blockers, clonidine, methyldopa, carbamazepine, phenytoin, baclofen, cyclobenzaprine, lithium, antidepressants (e.g., tricyclic antidepressants, selective serotonin reuptake inhibitors), and interleukin-2... 

Drugs that may be affected by tricyclic compounds include anticholinergics, carbamazepine, clonidine, dicumarol, grepafloxacin, guanethidine, levodopa, quinolones, sparfloxacin, and sympathomimetics. 

L-deprenyl (selegiline), a monoamine oxidase B inhibitor, clonidine and guanfacine, a2-adreno-receptor agonists, and levodopa (L-dopa) have been reported to improve cognitive function in some subjects. Zimeldine, citaloprani, and alaproclate — selective serotonin uptake blockers — have no beneficial effects. 

Levodopa Levodopa degraded in gut prior to reaching sites of absorption. Agents that alter gastrointestinal motility may alter degree of intraluminal degradation. Antiparkinsonism effect of levodopa susceptible to inhibition by other drugs. Clonidine [NE] Inhibits antiparkinsonism effect. 

Restless legs syndrome was a feature of opioid withdrawal on days 3-4 in two heroin-dependent individuals (55). They were treated with levodopa and clonidine. 

CENTRALLY ACTING ANTI HYPERTENSIVES LEVODOPA 1. Clonidine may oppose the effect of levodopa/ carbidopa 2. Methyldopa may 1 levodopa requirements, although there are case reports of deteriorating dyskinesias in some patients 1. Uncertain at present 2. Uncertain at present 1. Watch for deterioration in control of symptoms of Parkinson s disease 2. Levodopa needs may 1 in cases of worsening Parkinson s control, use an alternative antihypertensive... 

Clinically important, potentially hazardous interactions with alcohol, amiodarone, amphotericin B, cisapride, clonidine, digitalis, diltiazem, disopyramide, erythromycin, glucocorticoids, halofantrine, haloperidol, hypokalemic diruretics, imipramine antidepressants, levodopa, lithium, pentamidine, pimozide, quinidine, sotalol, stimulant laxatives, tetracosactides, thioridazine... 

These observations form the basis for provocative tests to assess the ability of the pituitary to secrete GH. Provocative stimuli include Arg, glucagon, insuhn-induced hypoglycemia, clonidine, and the dopamine precursor levodopa each can increase circulating GH levels in normal subjects within 45-90 minutes. 

Limited evidence suggests that clonidine may oppose the effects of levodopa. Be aware that, as with all antihypertensives, additive hypotensive effects may occur. 

A study in 2 patients taking levodopa with carbidopa found that concurrent treatment with clonidine (up to 1.5 mg daily for 10 to 24 days) caused a worsening of the parkinsonism (an exacerbation of rigidity and akinesia). The eoncurrent use of antimuscarinic drugs reduced the effects of this interaction. ... 

Another report on 10 hypertensive and 3 normotensive patients with Parkinson s disease, 9 of them taking levodopa and 4 of them not, claimed that concurrent treatment with clonidine did not affect the control of the parkinsonism. However, 2 patients stopped taking the clonidine because of an increase in tremor and gait disturbance. ... 

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