Levodopa


Generic Medicine Info
Indications and Dosage
Inhalation/Respiratory
Parkinson's disease
Adult: For intermittent treatment of episodic motor fluctuations (OFF episodes) in patients treated with levodopa/dopa-decarboxylase inhibitor (e.g. carbidopa): 84 mg via oral inhalation, up to 5 times daily as needed when symptoms of an OFF period return. Max: 84 mg/dose; 420 mg/day.
Administration
Should be taken with food. May be taken w/ meals to reduce GI discomfort. Keep a consistent diet.
Contraindications
Concomitant use or within 14 days of MAOIs use.
Special Precautions
Patient with history of psychotic disorder; major psychotic disorder, glaucoma, severe CV disease, respiratory disease. Avoid abrupt withdrawal or rapid dose reduction. Elderly. Pregnancy and lactation.
Adverse Reactions
Significant: Abnormal thinking and behavioural changes (e.g. agitation, aggressive behaviour, confusion, paranoid ideation, delirium, delusions, disorientation, and psychotic-like behaviour), impulse control or compulsive disorders (e.g. increased sexual urges, intense urges to spend money, pathological gambling, binge or compulsive eating), hallucinations that may be accompanied by confusion, insomnia and excessive dreaming; somnolence and falling asleep while engaged in activities of daily living; dyskinesia; withdrawal-emergent hyperpyrexia and confusion; bronchospasm, increased intraocular pressure.
Cardiac disorders: Chest discomfort.
Gastrointestinal disorders: Nausea, vomiting.
Injury, poisoning and procedural complications: Fall, laceration, skin abrasion.
Investigations: Increased bilirubin, decreased red blood cell count, positive direct Coomb's test.
Musculoskeletal and connective tissue disorders: Limb pain.
Nervous system disorders: Headache.
Psychiatric disorders: Insomnia.
Respiratory, thoracic and mediastinal disorders: Cough, upper respiratory tract infection, nasopharyngitis, pneumonia, bronchitis, sputum and nasal discharge discolouration, oropharyngeal pain, choking sensation.
Vascular disorders: Orthostatic hypotension.
Gastroenteral/PO: C (FDA pregnancy category C if used in combination therapy w/ carbidopa.)
Patient Counseling Information
This drug may cause drowsiness, somnolence or reduced alertness, if affected, do not drive or operate machinery.
Monitoring Parameters
Monitor LFT, BUN, CBC, direct antiglobulin, and intraocular pressure (in patients with glaucoma) as clinically indicated. Monitor for signs of CNS related side effects.
Overdosage
Symptoms: CNS disturbance, more severe psychiatric problems, risk of CV disturbance (e.g. tachycardia, hypotension), rhabdomyolysis and transient renal insufficiency. Management: Supportive treatment. For the development of arrhythmias, monitor ECG and antiarrhythmic therapy may be given as needed.
Drug Interactions
May enhance the orthostatic hypotensive effect of MAOI Type B (e.g. rasagiline, selegiline, safinamide). Diminished therapeutic effect with isoniazid and dopamine D2 receptor antagonists (e.g. metoclopramide, phenothiazines, butyrophenones, risperidone). Reduced bioavailability with iron salts or multivitamins/minerals (with A, D, E, K, folate). May enhance the hypotensive effect of antihypertensives.
Potentially Fatal: May enhance the adverse effect of MAOIs (e.g. phenelzine, tranylcypromine) particularly on the development of hypertensive reactions.
Lab Interference
False diagnosis for pheochromocytoma based on plasma and urine levels of catecholamines. False-positive reaction for urinary ketone bodies when a test tape is used for determination of ketonuria. False-negative tests may result with use of glucose-oxidase methods of testing for glucosuria.
Action
Description: Levodopa, a precursor of dopamine, crosses the blood-brain barrier and is converted to dopamine by striatal enzymes, thereby relieving the symptoms of Parkinson's disease.
Pharmacokinetics:
Absorption: Rapidly absorbed from the gastrointestinal tract. Bioavailability: Approx 70% (relative to availability from immediate-release formulation). Time to peak plasma concentration: Median: 0.5 hour (0.17-2 hours).
Distribution: Crosses the placenta and blood-brain barrier; enters breast milk. Apparent volume of distribution: 168 L. Plasma protein binding: Approx 10-30%.
Metabolism: Extensively metabolised via decarboxylation by L-aromatic amino acid decarboxylase to dihydrophenylacetic acid (DOPAC) and homovanillic acid (HVA) and O-methylation by catechol-O methyltransferase (COMT).
Excretion: Mainly via urine (80% as dihydroxyphenylacetic acid and homovanillic acid); faeces (as unchanged drug). Elimination half-life: 2.3 hours.
Chemical Structure

Chemical Structure Image
Levodopa

Source: National Center for Biotechnology Information. PubChem Database. Levodopa, CID=6047, https://pubchem.ncbi.nlm.nih.gov/compound/Levodopa (accessed on Jan. 21, 2020)

Storage
Store between 20-25°C. Protect from moisture. Store cap in original package and only remove immediately before use.
MIMS Class
Antiparkinsonian Drugs
ATC Classification
N04BA01 - levodopa ; Belongs to the class of dopa and dopa derivative dopaminergic agents. Used in the management of Parkinson's disease.
References
Buckingham R (ed). Levodopa. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 18/08/2021.

Inbrija (Acorda Therapeutics, Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 04/08/2021.

Inbrija 33 mg Inhalation Powder, Hard Capsules (Acorda Therapeutics Ireland Limited). European Medicines Agency [online]. Accessed 04/08/2021.

Levodopa (Oral Inhalation). Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 04/08/2021.

Levodopa. Gold Standard Drug Database in ClinicalKey [online]. Elsevier Inc. https://www.clinicalkey.com. Accessed 04/08/2021.

Disclaimer: This information is independently developed by MIMS based on Levodopa from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2021 MIMS. All rights reserved. Powered by MIMS.com
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