Carbidopa and levodopa: uses, appearance and warnings

DHIVY is indicated for the treatment of Parkinson’s disease, post-encephalitic parkinsonism, and symptomatic parkinsonism that may follow carbon monoxide intoxication or manganese intoxication. DHIVY is a combination of carbidopa (an aromatic amino acid decarboxylation inhibitor) and levodopa (an aromatic amino acid) indicated for the treatment of Parkinson’s disease, post-encephalitic parkinsonism, and symptomatic parkinsonism that may follow carbon monoxide intoxication or manganese intoxication ( 1 )

DHIVY tablets are white to off-white tablets containing 25 mg of carbidopa and 100 mg of levodopa. Each DHIVY tablet has 3 functional scores with each segment containing 6.25 mg of carbidopa and 25 mg of levodopa. Tablets: Carbidopa and levodopa 25 mg/100 mg, functionally scored. Each DHIVY tablet has 3 functional scores with each segment containing 6.25 mg of carbidopa and 25 mg of levodopa.( 3 )

16.1 How Supplied DHIVY (carbidopa and levodopa) tablets are white to off-white tablets with functional scoring containing 25 mg of carbidopa and 100 mg of levodopa. One side of each DHIVY tablet has 3 scores, with each segment containing 6.25 mg of carbidopa and 25 mg of levodopa (1:4 ratio). The unscored side of the tablet is debossed with logo “AV70l”. DHIVY is supplied as follows: NDC 75854-701-01 bottles of 100. Four copies of the Instructions for Use are included with the bottle, and additional copies, as needed, can be printed. 16.2 Storage and Handling Store at 20°C to 25°C (68°F to 77°F); excursions permitted between 15°C to 30°C (59°F to 86°F) [see USP Controlled Room Temperature]. Store in a tightly closed container, protected from light and moisture. Dispense in a light-resistant container.

DHIVY is contraindicated in patients Currently taking a nonselective monoamine oxidase (MAO) inhibitor (e.g., phenelzine, linezolid, and tranylcypromine) or have recently (within 2 weeks) taken a nonselective MAO inhibitor. Hypertension can occur if these drugs are used concurrently [see Drug Interactions ( 7.1 )] . With known hypersensitivity to any component of DHIVY [see Adverse Reactions (6 )]. Nonselective MAO inhibitors ( 4 ) With known hypersensitivity to any component of DHIVY ( 4 )

May cause falling asleep during activities of daily living ( 5.1 ) Avoid sudden discontinuation or rapid dose reduction to reduce the risk of withdrawal-emergent hyperpyrexia and confusion ( 5.2 ) Cardiovascular Ischemic Events: Monitor patients with a history of cardiovascular disease ( 5.3 ) Hallucinations/Psychosis may occur ( 5.4 ) Impulse Control/Compulsive Behaviors: Consider dose reduction or stopping DHIVY if impulse control disorders occur ( 5.5 ) May cause or exacerbate dyskinesia: Consider dose reduction ( 5.6 ) 5.1 Falling Asleep During Activities of Daily Living and Somnolence Patients taking carbidopa/levodopa alone or with other dopaminergic drugs have reported suddenly falling asleep without prior warning of sleepiness while engaged in activities of daily living, including the operation of motor vehicles which have resulted in accidents. Although many patients reported somnolence while on dopaminergic medications, some perceived that they had no warning signs (sleep attack), such as excessive drowsiness, and believed that they were alert immediately prior to the event. Sudden onset of sleep has been reported to occur more than one year after the initiation of treatment. It has been reported that falling asleep while engaged in activities of daily living usually occurs in a setting of pre-existing somnolence, although some patients may not give such a history. For this reason, prescribers should reassess patients for drowsiness or sleepiness in DHIVY-treated patients, especially since some of the events occur well after the start of treatment. Prescribers should be aware that patients may not acknowledge drowsiness or sleepiness until directly questioned about drowsiness or sleepiness during specific activities. Before initiating treatment with DHIVY, advise patients about the potential to develop drowsiness and ask specifically about factors that may increase the risk for somnolence with DHIVY such as the use of concomitant sedating medications and the presence of sleep disorders. Consider discontinuing DHIVY in patients who report significant daytime sleepiness or episodes of falling asleep during activities that require active participation (e.g., conversations, eating, etc.). If treatment with DHIVY continues, advise patients not to drive and to avoid other potentially dangerous activities that might result in harm if the patients become somnolent. There is insufficient information to establish that dose reduction will eliminate episodes of falling asleep while engaged in activities of daily living. 5.2 Withdrawal-Emergent Hyperpyrexia and Confusion A symptom complex that resembles neuroleptic malignant syndrome (characterized by elevated temperature, muscular rigidity, altered consciousness, and autonomic instability), with no other obvious etiology, has been reported in association with rapid dose reduction, withdrawal of, or changes in dopaminergic therapy. Avoid sudden discontinuation or rapid dose reduction in patients taking DHIVY. If the decision is made to discontinue DHIVY, the dose should be tapered to reduce the risk of hyperpyrexia and confusion [see Dosage and Administration ( 2.3 ) ] . 5.3 Cardiovascular Ischemic Events In patients with a history of myocardial infarction who have residual atrial, nodal, or ventricular arrhythmias, cardiac function should be monitored in an intensive cardiac care facility during the period of initial dosage adjustment. 5.4 Hallucinations/Psychotic-Like Behavior Hallucinations and psychotic-like behavior have been reported with dopaminergic medications. In general, hallucinations present shortly after the initiation of therapy and may be responsive to dose reduction in levodopa. Hallucinations may be accompanied by confusion, sleep disorder (insomnia), and excessive dreaming. Abnormal thinking and behavior may present with one or more symptoms, including paranoid ideation, delusions, hallucinations, confusion, psychotic-like behavior, disorientation, aggressive behavior, agitation, and delirium. Patients with a major psychotic disorder should not be treated with DHIVY, because of the risk of exacerbating psychosis. In addition, medications that antagonize the effects of dopamine used to treat psychosis may exacerbate the symptoms of Parkinson’s disease and may decrease the effectiveness of DHIVY [see Drug Interactions ( 7.2 ) ] . 5.5 Impulse Control/Compulsive Behaviors Case reports suggest that patients can experience an intense urge to gamble, increased sexual urges, intense urges to spend money, binge eating, and/or other intense urges, and the inability to control these urges while taking one or more of the medications, including DHIVY, that increase central dopaminergic tone and that are generally used for the treatment of Parkinson’s disease. In some cases, although not all, these urges were reported to have stopped when the dosage was reduced or the medication was discontinued. Because patients may not recognize these behaviors as abnormal, it is important for prescribers to specifically ask patients or the caregivers about the development of new or increased gambling urges, sexual urges, uncontrolled spending, or other urges while being treated with DHIVY. Consider dosage reduction or stopping the medication if a patient develops such urges while taking DHIVY. 5.6 Dyskinesia DHIVY can cause dyskinesias that may require a dosage reduction of DHIVY or other medications used for the treatment of Parkinson’s disease. 5.7 Vitamin B6 Deficiency and Seizures Treatment with carbidopa-levodopa, including DHIVY, contribute to reduced Vitamin B6 levels. Higher doses of carbidopa/levodopa may increase the risk of vitamin B6 deficiency. Seizures associated with vitamin B6 deficiency have been reported in the postmarketing setting in patients taking carbidopa-levodopa. In these reported cases, seizures were refractory to traditional antiseizure medications and only resolved after vitamin B6 administration. …

The following serious adverse reactions are discussed below and elsewhere in the labeling: Falling Asleep During Activities of Daily Living and Somnolence [see Warnings and Precautions (5.1 )] Withdrawal-Emergent Hyperpyrexia and Confusion [see Warnings and Precautions ( 5.2) ] Cardiovascular Ischemic Events [see Warnings and Precautions ( 5.3) ] Hallucinations/Psychotic-Like Behavior [see Warnings and Precautions ( 5.4) ] Impulse Control/Compulsive Behaviors [see Warnings and Precautions ( 5.5 )] Dyskinesia [see Warnings and Precautions ( 5.6 )] Vitamin B6 Deficiency and Seizures [see Warnings and Precautions ( 5.7 )] Peptic Ulcer Disease [see Warnings and Precautions ( 5.8 )] Glaucoma [see Warnings and Precautions ( 5.9 )] Depression/Suicidality [see Warnings and Precautions ( 5.11 )] The most common adverse reactions reported with carbidopa/levodopa tablets have included dyskinesias, …

Iron salts and dopamine D2 antagonists including metoclopramide: May reduce the effectiveness of DHIVY ( 7.2 , 7.3 ) 7.1 Monoamine Oxidase (MAO) Inhibitors The use of nonselective MAO inhibitors with DHIVY is contraindicated [see Contraindications ( 4 ) ] . Discontinue use of any nonselective MAO inhibitors at least two weeks prior to initiating DHIVY. DHIVY may be administered concomitantly with the manufacturer's recommended dose of selective MAO-B inhibitors (e.g., rasagiline or selegiline HCl). Concomitant therapy with selegiline and carbidopa/levodopa may be associated with severe orthostatic hypotension not attributable to carbidopa/levodopa alone. 7.2 Dopamine D 2 Receptor Antagonists and Isoniazid Dopamine D 2 receptor antagonists (e.g., phenothiazines, butyrophenones, risperidone) and isoniazid may reduce the effectiveness of levodopa. …