Carbidopa DI

Question 1

MoA of carbidopa

Answer 1

Noncompetitive dopa decarboxylase inhibitor → inhibits peripheral L-dopa metabolism → increases the absorption and half-life of L-dopa

Question 2

Carbidopa PK/PD

Answer 2

Doesn’t cross the BBB, mostly renally eliminated

Question 3

Does carbidopa have any pharmacologic action?

Answer 3

NO! DON’T USE IT AS MONOTHERAPY EVER! USE WITH L-DOPA!

Question 4

CIs of carbidopa

Answer 4

pregnancy and lactation

Question 5

Ratios of carbidopa:L-dopa available

Answer 5

1:10, 1:4

Question 6

Switching from CR Sinemet to IR Sinemet

Answer 6

Start with a 50% reduction in FREQUENCY and consider giving 25% MORE of CR dose due to decreased bioavailability

Question 7

Sinemet CR does what to the “off” time?

Answer 7

Decreases in the total “off” time and decreases dosing frequency too

Can supplement with Sinemet IR in the AM if patients complain of delayed onset of effect and can help with morning rigidity

Question 8

Inbrija formulation

Answer 8

Inhaled formulation of L-dopa (inhaled capsules)

Question 9

Inbrija indication

Answer 9

Used PRN in treatment of “off” episodes in PD patients treated with carbidopa/L-dopa (up to 5 doses/day)

IT IS NOT A REPLACEMENT!

Question 10

Inbrija is not recommended in patients with what comorbidities?

Answer 10

COPD, asthma, basically any underlying chronic lung disease

Question 11

Inbrija ADEs

Answer 11

somnolence, hallucinations, dyskinesia, cough, nausea, URTI, sputum discoloration

Question 12

Inbrija DDIs

Answer 12

Nonselective MAOI use within 2 weeks