Meds and you

27 September 2013

Levodopa

Levodopa is an antiparkinsonism agent. Antiparkinsonism agents are drugs that relieve the symptoms of Parkinsonism.

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(Also known as L-dopa)

Levodopa is not available as a product on its own.

General information
Levodopa is an antiparkinsonism agent. Antiparkinsonism agents are drugs that relieve the symptoms of Parkinsonism and are effective in countering the involuntary muscle movement often associated with the disease.

In South Africa levodopa is registered for the treatment of Parkinson's disease.

Levodopa is rarely used on its own, and is usually combined with either carbidopa or bensarezide to increase the effect of levodopa in the brain and to reduce the drugs side-effects.

For this medication to be effective it has to be taken regularly, even if you do not notice an immediate effect. The decision to stop using this medication should only be made by your doctor as a sudden discontinuation of treatment may worsen the symptoms of Parkinson's disease.

Levodopa may cause your urine to appear dark or slightly reddish. This is normal and is no cause for concern.

It should be noted that because this drug may cause dizziness, light-headedness and/or sedation, driving and any hazardous tasks should be avoided until you know how this medication affects you.

How does levodopa work?
Levodopa increases dopamine levels in the brain, a chemical messenger in the brain of which a shortage causes Parkinson's disease.

Fast facts

Drug schedule: schedule 4
What does it do? Levodopa reduces the symptoms of Parkinson’s disease.
Overdose risk: medium
Dependence risk: low
Is levodopa available on prescription only? yes

User information

Onset of effect: it may take several months for the full therapeutic response to be seen.
Duration of action: 6-12 hours
Dietary advice: levodopa should be taken shortly after a meal to reduce gastrointestinal side effects. High protein diets may however reduce the effect of this drug.
Stopping this medicine: do not stop taking this drug without consulting your doctor. A sudden discontinuation of treatment may cause worsening of Parkinson's disease.
Prolonged use: a decline in effect may be seen with prolonged use, warranting an increase in dose. This may cause an increase in side-effects to the extent that treatment with the drug may eventually have to be discontinued.

Special precautions
Consult your doctor before using this drug if:

  • you are currently being, or in the last 14 days have been, treated with monoamine oxidase inhibitor antidepressants
  • you have liver or kidney disease
  • you have glaucoma
  • you have skin cancer
  • you have heart disease
  • you have high blood pressure
  • you have a stomach or duodenal ulcer
  • you have depression
  • you have a history of mental health problems
  • you are younger than 25
  • you have a history of seizures
  • you are asthmatic or have been diagnosed with chronic obstructive pulmonary disease
  • you have diabetes

Pregnancy: avoid. It is unknown how this medication may affect your baby. Consult your doctor before using this drug, or if you are planning to fall pregnant.
Breastfeeding: avoid. It is unknown how this medication may affect your baby. Consult your doctor before use.
Porphyria: avoid. It is unknown how this medication may affect your condition. Consult your doctor before use.
Infants and children: this medication is not intended for use in children under the age of 12 years.
The elderly: caution is advised in the elderly as side effects are more likely to occur.
Driving and hazardous work: caution is advised as use of this medication may lead to dizziness, light-headedness and/or sedation. Avoid such activities until you know how this medication affects you.
Alcohol: avoid concomitant use of alcohol with this medication.

Possible side effects

Side Effect
Frequency
Consult your doctor

Common
Rare
Only if severe
In all cases
nausea/vomiting
X

X

loss of appetite
X

X

dark urine
X

X

constipation
X

X

low blood pressure
X

X

dizziness

X

X
anxiety

X

X
confusion

X

X
nightmares

X

X
visual disturbances

X

X
palpitations

X

X
abdominal pain

X

X
black stools

X

X

Interactions
Drug interactions

antacids risk of increased levodopa absorption
anticholinergic drugs risk of reduced levodopa absorption
blood pressure medication risk of enhanced drop in blood pressure
antipsychotics may inhibit the effect of levodopa. it is advised to use antipsychotics such as clozapine, olanzapine and quetiapine which exert less of an effect on dopamine
benzodiazepines may reduce the antiparkinsonian effect of levodopa
clonidine may reduce the antiparkinsonian effect of levodopa
papaverine may reduce the antiparkinsonian effect of levodopa
phenothiazines may reduce the antiparkinsonian effect of levodopa
phenytoin may reduce the antiparkinsonian effect of levodopa
iron salts binds to levodopa and may reduce the antiparkinsonian effect of levodopa. Separate doses by at least 2 hours
abacavir may reduce the antiparkinsonian effect of levodopa
pyridoxine may reduce the antiparkinsonian effect of levodopa
taccrine may reduce the antiparkinsonian effect of levodopa
tricyclic antidepressants may reduce the antiparkinsonian effect of levodopa. rare increases in blood pressure have also been reported
bupropion increased risk of side effects with levodopa
furazolidine increased risk of side effects with levodopa
linezolid increased risk of side effects with levodopa
metoclopramide increased risk of side effects with levodopa
methyldopa increased risk of side effects with levodopa
monoamine oxidase inhibitor antidepressants risk of hypertensive crisis

Disease interactions
Consult your doctor before using this drug if you have liver or kidney disease, glaucoma, skin cancer, heart disease, high blood pressure, a stomach or duodenal ulcer, depression, a history of mental health problems, a history of seizures, or if you are asthmatic or have been diagnosed with chronic obstructive pulmonary disease.

Overdose action
A small overdose is no cause for concern. In case of intentional large overdose, seek emergency medical attention.

Recommended dosage
Dose: treatment should be initiated gradually. Treatment is usually started with 300 mg/day in 3 divided doses. This dose can be increased by 100 mg/day every 3-7 days until a response is seen, or a maximum daily dose of 8000 mg is reached.

Interesting fact
Levodopa, co-administered with a peripheral DOPA decarboxylase inhibitor, has been tested as a possible treatment for restless leg syndrome.

This material is not intended to substitute medical advice, but is for informational purposes only. Please consult a physician for specific treatment and recommendations.

 
 

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