Levodopa + Carbidopa

Aldopa tablet is indicated for the treatment of Parkinson's disease and syndrome. It is useful in relieving many of the symptoms of parkinsonism, particularly rigidity and bradykinesia. This tablet is frequently helpful in the management of tremor, dysphagia, sialorrhea and postural instability associated with Parkinson's disease and syndrome. Levodopa plus carbidopa before physiotherapy increases motor recovery after stroke.

Dosage & Administration

100/10 mg tablet
: Dosage may be initiated with one tablet three or four times a day. Titration upward may be required in some patients to achieve optimum dosage of carbidopa. The dosage may be increased by one tablet every day or every other day until a total of eight tablets (two tablets q.d.s.) is reached.
250/25 mg tablet
: The initial dose is one half taken once or twice daily. However, this may not provide the optimal amount of Carbidopa needed by many patients. If necessary, add one-half every day or every other day until optimal response is reached. The suggested starting dosage for most patients taking more than 1500 mg of Levodopa a day is one tablet of 250/25 mg three or four times a day.
100/25 mg tablet
: When Levodopa 100 mg & Carbidopa 25 mg tablet is used, dosage is initiated with 1 tablet of Levodopa 100 mg & Carbidopa 25 mg tablet, 3 times a day. This dosage schedule provides 75 mg of carbidopa per day. Dosage may be increased by 1 tablet every day or every other day, as necessary, until a dosage of 8 tablets of Levodopa 100 mg &
Carbidopa 25 mg a day is reached.
50/12.5 mg tablet
: One tablet three or four times a day
Maintenance dose
: Therapy should be individualized and adjusted according to the desired therapeutic response. When more levodopa is requried, 250/25 mg tablet should be substituted at a dosage of one tablet three or four times a day. If necessary, the dosage of 250/25 mg tablet may be increased by half to one tablet every other day to a maximum of eight tablets a day. Experience with a total daily dosage greater than 200 mg Carbidopa is limited.

Adverse effects that occur frequently in patients receiving Carbidopa-Levodopa are those due to the central neuropharmacologic activity of dopamine. These reactions usually can be diminished by dosage reduction. The most common adverse effects are dyskinesias including choreiform, dystonic, and other involuntary movements and nausea.
Body as a whole
: syncope, chest pain, anorexia.
Cardiovascular
: palpitation, orthostatic effects including hypotensive episodes, hypertension, phlebitis.
Gastrointestinal
: vomiting, gastrointestinal bleeding, development of duodenal ulcer, diarrhoea, dark saliva.
Haemotologic
: leukopenia, haemolytic and non-haemolytic anaemia, thrombocytopenia, agranulocytosis.
Hypersensitivity
: angioedema, urticaria, pruritus, Henoch-Schonlein purpura.
Nervous System
: dizziness, somnolence, paresthesia, delusions, hallucinations and paranoid ideation, depression with or without development of suicidal tendencies, dementia, dream abnormalities, agitation, confusion, increased libido.
Respiratory
: dyspnea.
Skin
: alopecia, rash, dark sweat.
Urogenital
: dark urine.

Levodopa, the metabolic precursor of dopamine, crosses the blood-brain barrier and is converted to dopamine in the brain. Carbidopa is a dopa decarboxylase (DDC) inhibitor which reduces the peripheral metabolism of Levodopa to dopamine, and thus, more Levodopa becomes available to the brain.
Levodopa
: Levodopa is the metabolic precursor of dopamine, does cross the blood-brain barrier, and presumably is converted to dopamine in the brain. This is thought to be the mechanism whereby levodopa relieves symptoms of Parkinson's disease.
Carbidopa
: When levodopa is administered orally, it is rapidly decarboxylated to dopamine in extracerebral tissues so that only a small portion of a given dose is transported unchanged to the central nervous system. Carbidopa inhibits the decarboxylation of peripheral levodopa, making more levodopa available for delivery to the brain.