Carbidopa and Levodopa CR Tablets

Drug Name: (Xining) Carzobidopa Sustained Release Tablets

Common Name: Carzobidopa Sustained Release Tablets

Brand Name: Xining

Dosage Form: Tablet

Functions and indications:

Primary Parkinson's disease. Postencephalitic parkinsonism, symptomatic parkinsonism, Parkinson's disease or parkinsonism in patients taking vitamin preparations containing pyridoxine.

Usage and dosage:

The ratio of carbidopa to levodopa in this product is 1:4. Each 50 mg/200 mg tablet contains 50 mg carbidopa and 200 mg levodopa. This product is a half-dose dosage form of 25 mg/100 mg. Each tablet contains 25 mg of carbidopa and 100 mg of levodopa. The daily dose of this product must be carefully adjusted and determined. Patients should be closely monitored during dose adjustment, with particular attention to the emergence or worsening of nausea or abnormal involuntary movements including dyskinesia, chorea, and dystonia.

This product 50 mg/200 mg can be taken as a whole tablet or half a tablet, and this product 25 mg/100 mg can only be taken as a whole tablet. This method of taking can maintain the controlled-release properties of the tablets, and the tablets cannot be chewed or crushed. While taking this product, other standard anti-Parkinson's disease medications may be continued in addition to levodopa, but dosage adjustments are required.

Because carbidopa can prevent the reversal of the effects of levodopa caused by pyridoxine, this product can be used in patients receiving supplementary therapy with pyridoxine.

Starting dose

Patients who have not received levodopa treatment:

This product 25 mg/100 mg is specially designed for early-stage patients who have never received levodopa treatment. It can also be used to assist patients taking this product 50 mg/200 mg for dose adjustment. The recommended starting dose of this product is 25 mg/100 mg, one tablet twice daily. For patients who need more levodopa, 25 mg/100 mg of this product can be taken 1-4 tablets per day in two divided doses, which is generally well tolerated.

50 mg/200 mg of this product can also be used as initial treatment when appropriate. The recommended starting dose of 50 mg/200 mg is 1 tablet 2 to 3 times daily. The starting dose of levodopa should not be higher than 600 mg per day or the interval between doses should not be shorter than 6 hours.

Patients being treated with traditional levodopa/decarboxylase inhibitor combinations

The dose of 50 mg/200 mg of this product should first be adjusted to provide approximately 10% more levodopa than the original daily supply, although depending on clinical efficacy, the levodopa dose may need to be increased by 30%. (See Dosage and Administration, Dose Adjustment). Dosing intervals of 50 mg/200 mg during the day should be 4 to 8 hours. (See Clinical Pharmacology, Pharmacokinetics).

The medication guide for replacing the traditional levodopa/decarboxylase inhibitor compound preparation with 50 mg/200 mg of this product is shown in the table below:

The medication switching guide from the traditional levodopa/decarboxylase inhibitor compound preparation to 50 mg/200 mg of this product

L-dopa/decarboxylase inhibitor This product is 50 mg/200 mg

Total daily dose of levodopa (mg)* Recommended dose range

300-400 2 times a day, 1 tablet each time

500-600 2 times a day, 1.5 tablets each time or 3 times a day, 1 tablet each time

700-800 Take 4 tablets daily divided into 3 or more times (for example, 1.5 tablets in the morning, 1.5 tablets in the afternoon and 1 tablet in the evening)

900-1000 Take 5 tablets in three or more times a day (for example, 2 tablets in the morning, 2 tablets in the afternoon and 1 tablet in the evening)

*Starting dose - Dosage range is not listed in the table. See usage and dosage

When the gradient required for dose adjustment is 100 mg, you can take 25 mg/100 mg of this product. At the same time, this specification can also replace half a tablet of 50 mg/200 mg of this product.

Patients being treated with levodopa alone

Before starting to take this product 50 mg/200 mg, levodopa must have been stopped for 8 hours or more. For patients with mild to moderate disease, the recommended starting dose of this product 50 mg/200 mg is one tablet 2 or 3 times a day.

Dose adjustment

When starting treatment, the dose and medication interval can be adjusted according to the therapeutic effect. The appropriate dosage for most patients is 12-8 tablets of 50 mg/200 mg per day, taken in divided doses, with a dosage interval of 4 to 12 hours during the day. Larger doses (up to 12 tablets) and shorter dosing intervals (less than 4 hours) have been used, but this is generally not recommended.

When the dosing interval of 50 mg/200 mg of this product is less than 4 hours or the divided doses are unequal, it is recommended to give a smaller dose in the last dose of each day. For some patients, the onset of action after taking the first dose of this product in the morning is one hour later than usual.

It is recommended that the interval between each dosage adjustment should be no less than 3 days.

Maintenance dose

Since Parkinson's disease is progressive, it is recommended to conduct regular clinical evaluation and adjust the medication regimen of this product as needed.

Adding other anti-Parkinson's disease drugs

Anticholinergic agents, dopamine agonists and amantadine can be taken simultaneously with this product. When these drugs are used concomitantly to intensify the treatment regimen, dose adjustments may be required.

For some patients with progressive disease, if they need to increase the amount of levodopa in a short period of time during the day, levodopa tablets 10 mg/100 mg or 25 mg/100 mg (half tablet or half) can be added to the dosage regimen of levodopa controlled-release tablets.

Discontinue treatment

If it is necessary to suddenly reduce or interrupt the use of this product, the patient should be closely observed, especially those taking antipsychotic drugs (see Precautions).

If the patient requires general anesthesia, this product can be continued as long as the patient is allowed to take oral medications. If treatment is temporarily interrupted, the usual dose should be administered as soon as the patient is able to take the drug orally.

Adverse reactions:

In controlled clinical trials in patients with moderate to severe movement disorders, this product did not produce any adverse reactions unique to controlled-release preparations.

The most common adverse reaction is dyskinesia (an abnormal involuntary movement). Because the "on" time (sometimes accompanied by dyskinesia) replaces the "off" time (which can be reduced by this product), the incidence of dyskinesia is slightly higher with this product than with regular tablets.

Other common adverse reactions (more than 2%) include: nausea, hallucinations, confusion, dizziness, chorea and dry mouth.

Rarely occurring adverse reactions (1-2%) include: abnormal dreams, dystonia, drowsiness, insomnia, depression, weakness, vomiting and anorexia.

Other adverse reactions reported in clinical studies and post-marketing include:

Systemic: chest pain, syncope

Cardiovascular: palpitations, orthostatic effects including episodes of hypotension

Gastrointestinal: constipation, diarrhea, dyspepsia, gastrointestinal pain, dark saliva

Hypersensitivity: angioedema, rubella, pruritus< /p>

Metabolism: Weight loss

Nervous/psychiatric system: Neuroleptic malignant syndrome (see Precautions), agitation, anxiety, decreased brain reactivity, paresthesia, disorientation, fatigue, headache, extrapyramidal and movement disorders, falls, gait abnormalities, muscle spasms, on-off phenomenon, increased libido, psychotic episodes including delusions and paranoid-like ideation effects.

In drug marketing applications, it has been rare for patients to develop pathological or compulsive gambling due to the use of levodopa and/or dopamine receptor agonists.

Respiratory system: dyspnea

Skin: facial flushing, hair loss, rash, dark sweat

Special sensations: blurred vision

Urinogenital system: dark urine

Other reported or potential adverse reactions of levodopa or compound levodopa/carbidopa preparations and this product:

Cardiovascular system: arrhythmia, hypertension, phlebitis.

Gastrointestinal tract: bitter mouth, salivation, difficulty swallowing, bruxism, hiccups, gastrointestinal bleeding, abdominal distension, burning tongue, development of duodenal ulcer.

Hematological system: leukopenia, hemolytic and non-hemolytic anemia, thrombocytopenia, agranulocytosis.

Nervous/psychiatric system: ataxia, numbness, increased hand tremor, muscle twitching, blepharospasm, trismus, induction of latent Homer's syndrome, euphoria and dementia, depression with suicidal tendencies.

Skin: excessive sweating

Special sensations: diplopia, pupil dilation, eye movement crisis.

Genitourinary system: urinary retention, urinary incontinence, priapism.

Others: Weight gain, edema, weakness, weakness, hoarseness, general malaise, heat reflex, irritation, abnormal breathing patterns, neuroleptic malignant syndrome, malignant melanoma (see contraindications), Henoch-Schonlein purpura.

Convulsions have occurred, but their relationship to levodopa or carbidopa/levodopa has not been determined.

Laboratory tests: Abnormal laboratory tests that have been reported are: creatinine, uric acid, alkaline phosphatase, SGOT (AST), SGPT (ALT), lactate dehydrogenase, bilirubin, blood urea nitrogen, and Coombs test.

Reduced hemoglobin and hematocrit, increased blood sugar and white blood cells, bacteriuria and hematuria have also been reported. Carbidopa/levodopa combination preparations can cause false positive reactions in urine ketone dipstick tests to measure ketonuria, and this reaction will still occur even if the urine specimen is boiled. False negatives may occur when measuring urine glucose using the glucose oxidase method.

Contraindications:

Those who are using monoamine oxidase inhibitors must stop taking them for at least 2 weeks before using this medicine. It is contraindicated in patients who are allergic to any component of this medicine, suffer from narrow-angle glaucoma, suspected skin cancer, or have a history of melanoma.

Note:

If you have been treated with levodopa alone, you must stop taking levodopa for at least 8 hours before using Xining controlled-release tablets (if it is sustained-release levodopa, you need to stop taking it for at least 12 hours).

Use with caution in patients who have suffered from or have mental illness, severe cardiovascular or pulmonary disease, bronchial asthma, liver/kidney or endocrine system diseases, a history of gastric ulcer or convulsions, atrial, nodal or ventricular arrhythmias, a recent history of myocardial infarction, and chronic open-angle glaucoma.

Not recommended for the treatment of drug-induced extrapyramidal reactions.

During long-term treatment, regular examinations of liver, hematopoietic system, cardiovascular system and renal function should be carried out.

Laboratory tests: Abnormal results include liver function tests such as alkaline phospholipase, SGOT, SGPT, lactate dehydrogenase, bilirubin, blood urea nitrogen, and a positive Coombs' test. May cause false positive reaction of urinary ketones. False negatives may also occur when measuring glycosuria using the glucose oxidase method.

Drug interactions:

Used together with certain antihypertensive drugs, it can produce orthostatic hypotension. Hypertension and movement disorders are rare when used together with tricyclic antidepressants. Phenothiazines and butyrophenones may reduce the efficacy of levodopa. Phenytoin and papaverine can also reverse the effects of levodopa in Parkinson's disease.