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Crexont
carbidopa/ levodopa
Adult Dosing .
Dosage forms: ER CAP: 35 mg/140 mg, 52.5 mg/210 mg, 70 mg/280 mg, 87.5 mg/350 mg
Special Note
- [equivalency or interchangeability info]
- Info: carbidopa/levodopa ER cap not interchangeable with ER tab; do not substitute on a mg to mg basis; may interchange with other ER cap at approximately mg to mg basis
parkinsonism
- [levodopa-naive patients]
- Dose: individualize dose PO bid; Start: 35 mg/140 mg PO bid x3 days; Max: 525 mg/2100 mg per day; Info: titrate dose to optimal effect; dosing frequency may be incr. up to qid if needed; use lowest effective dose; may open cap, but do not crush/chew contents; taper dose gradually to D/C
- [conversion from IR levodopa <500 mg/day, most frequent single-dose 100 mg]
- Dose: individualize dose PO bid; Start: 70 mg/280 mg PO bid x1-3 days; Max: 525 mg/2100 mg per day; Info: titrate dose to optimal effect; dosing frequency may be incr. up to qid if needed; use lowest effective dose; may open cap, but do not crush/chew contents; taper dose gradually to D/C
- [conversion from IR levodopa <500 mg/day, most frequent single-dose 150 mg]
- Dose: individualize dose PO bid; Start: 105 mg/420 mg PO bid x1-3 days; Max: 525 mg/2100 mg per day; Info: titrate dose to optimal effect; dosing frequency may be incr. up to qid if needed; use lowest effective dose; may open cap, but do not crush/chew contents; taper dose gradually to D/C
- [conversion from IR levodopa <500 mg/day, most frequent single-dose 200 mg]
- Dose: individualize dose PO bid; Start: 140 mg/560 mg PO bid x1-3 days; Max: 525 mg/2100 mg per day; Info: titrate dose to optimal effect; dosing frequency may be incr. up to qid if needed; use lowest effective dose; may open cap, but do not crush/chew contents; taper dose gradually to D/C
- [conversion from IR levodopa >500 mg/day, most frequent single-dose 100 mg]
- Dose: individualize dose PO tid; Start: 70 mg/280 mg PO tid x1-3 days; Max: 525 mg/2100 mg per day; Info: titrate dose to optimal effect; dosing frequency may be incr. up to qid if needed; use lowest effective dose; may open cap, but do not crush/chew contents; taper dose gradually to D/C
- [conversion from IR levodopa >500 mg/day, most frequent single-dose 150 mg]
- Dose: individualize dose PO tid; Start: 105 mg/420 mg PO tid x1-3 days; Max: 525 mg/2100 mg per day; Info: titrate dose to optimal effect; dosing frequency may be incr. up to qid if needed; use lowest effective dose; may open cap, but do not crush/chew contents; taper dose gradually to D/C
- [conversion from IR levodopa >500 mg/day, most frequent single-dose 200 mg]
- Dose: individualize dose PO tid; Start: 140 mg/560 mg PO tid x1-3 days; Max: 525 mg/2100 mg per day; Info: titrate dose to optimal effect; dosing frequency may be incr. up to qid if needed; use lowest effective dose; may open cap, but do not crush/chew contents; taper dose gradually to D/C
- [conversion from IR levodopa >500 mg/day, most frequent single-dose >200 mg]
- Dose: individualize dose PO tid; Start: 175 mg/700 mg PO tid x1-3 days; Max: 525 mg/2100 mg per day; Info: titrate dose to optimal effect; dosing frequency may be incr. up to qid if needed; use lowest effective dose; may open cap, but do not crush/chew contents; taper dose gradually to D/C
renal dosing
- [not defined]
- renal impairment: not defined
- HD/PD: not defined
hepatic dosing
- [not defined]
Peds Dosing .
Peds dosing is currently unavailable or not applicable for this drug.
Contraindications / Cautions .
- hypersensitivity to drug or ingredient
- non-selective MAO inhibitor use within 14 days
- psychotic disorder, major
- glaucoma, angle-closure
- abrupt withdrawal
- avoid: alcohol use
- caution: CNS depressant use, concurrent
- caution: diet, high-protein
- caution: hepatic impairment
- caution: renal impairment
- caution: sleep disorder
- caution: dyskinesia
- caution: cardiovascular disease, severe
- caution: arrhythmia with MI history
- caution: pulmonary disease, severe
- caution: asthma
- caution: endocrine disease
- caution: PUD
- caution: GI bleeding history
- caution: glaucoma, open-angle
- caution: vitamin B6 deficiency
Drug Interactions .
Overview
carbidopa
dopa-decarboxylase inhibitor
- binds to polyvalent cations
- dopa-decarboxylase inhibitor
- potential for modified drug release
- avoid combo with beverages or products containing ethanol and Crexont; combo may incr. carbidopa release rate, levels, risk of adverse effects, decr. duration of efficacy
levodopa
dopamine precursor
- affected by altered gastrointestinal motility
- affects growth hormone diagnostic test results
- binds to polyvalent cations
- CNS depression
- dopamine agonist
- gastric pH sensitive
- hypotensive effects
- potential for modified drug release
- add MAO inhibitor to Interaction Check if recent (14 days) use
- avoid combo with beverages or products containing ethanol and Crexont; combo may incr. levodopa release rate, levels, risk of adverse effects, decr. duration of efficacy
Contraindicated
Avoid/Use Alternative
Monitor/Modify Tx
Caution Advised
Adverse Reactions .
Serious Reactions
- dyskinesia
- bradykinesia
- hypotension, orthostatic
- syncope
- MI
- arrhythmia
- sudden sleep episodes
- depression
- suicidal ideation
- suicide attempt
- hallucinations
- psychosis
- GI bleeding
- blood dyscrasia
- hypersensitivity reaction
- NMS-like symptoms if abrupt D/C
- seizures, vitamin B6 deficiency-associated
Common Reactions
- nausea
- dizziness
- headache
- dyskinesia
- insomnia
- abnormal dreams
- xerostomia
- anxiety
- constipation
- vomiting
- hypotension, orthostatic
- hallucinations
- confusion
- UTI
- depression
- body fluid discoloration, dark
- mood changes
- compulsive behaviors
Safety/Monitoring .
Monitoring Parameters
vitamin B6 level at baseline, then periodically; BUN/Cr, CBC, LFTs if extended tx; IOP if glaucoma; cardiac function if extended tx or during initial inpatient dose adjustment then periodically thereafter if arrhythmias with MI history
Look/Sound-Alike Drug Names
levodopa/carbidopa confused with: carbidopa
Pregnancy/Lactation .
Pregnancy
Clinical Summary
weigh risk/benefit during pregnancy; risk of teratogenicity not expected based on limited human data; possible risk of teratogenicity based on conflicting animal data at greater than MRHD
Lactation
Clinical Summary
carbidopa: weigh risk/benefit while breastfeeding; inadequate human data available to assess risk of infant harm; no human data available to assess effects on milk production
levodopa: weigh risk/benefit while breastfeeding; no known risk of infant harm based on limited human data; inadequate human data available, though theoretical decr. milk production based on decr. prolactin levels
Pharmacology .
Metabolism: for carbidopa: unknown; CYP450: unknown; for levodopa: decarboxylation, O-methylation; CYP450: unknown; Info: active metabolite (dopamine)
Excretion: for carbidopa: urine primarily (30% unchanged); Half-life: 2h; for levodopa: urine; Half-life: 2h; Info: half-life may be prolonged due to continuous absorption
Subclass: Dystonias/Parkinson Disease
Mechanism of Action
for carbidopa: inhibits peripheral levodopa decarboxylation; for levodopa: crosses blood-brain barrier and serves as dopamine precursor
Formulary .
No Formulary Selected
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