Levodopa

Inhalation/Respiratory
Parkinson's disease

Should be taken with food. May be taken w/ meals to reduce GI discomfort. Keep a consistent diet.

Concomitant use or within 14 days of MAOIs use.

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.

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.)

This drug may cause drowsiness, somnolence or reduced alertness, if affected, do not drive or operate machinery.

Monitor LFT, BUN, CBC, direct antiglobulin, and intraocular pressure (in patients with glaucoma) as clinically indicated. Monitor for signs of CNS related side effects.

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.

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.

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.

Description:
Mechanism of Action: 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.

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

Store between 20-25°C. Protect from moisture. Store cap in original package and only remove immediately before use.

Antiparkinsonian Drugs

N04BA01 - levodopa ; Belongs to the class of dopa and dopa derivative dopaminergic agents. Used in the management of Parkinson's disease.

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.