NancyMays,
The honest answer is maybe—but not everyone with Parkinson’s needs carbidopa-levodopa at night. That decision should be made with your neurologist or movement-disorder specialist based on what happens between bedtime and morning.

A nighttime dose may be considered when medication wears off overnight and symptoms interfere with sleep or safety. Examples include stiffness or tremor, painful cramping or dystonia, difficulty turning in bed, being unable to get up safely for the bathroom, or waking very slow and stiff before the first morning dose works. Carbidopa-levodopa treats Parkinson’s motor symptoms; it is not simply a sleeping pill.

If you sleep comfortably, move safely at night, and do reasonably well when you awaken, an extra dose may offer little benefit and could add side effects.  Doctors judge from your symptoms, examination, medication schedule, how long each dose works, overnight “off” periods, and response to levodopa.

The formulation matters. Immediate-release carbidopa-levodopa acts for a shorter time. Some people use controlled- or extended-release medication at bedtime for longer coverage, although its absorption and benefit can vary. Others may need the timing of their last daytime dose changed rather than an additional dose. Only the prescriber should decide the dose and formulation.

Nighttime problems are not always caused by low dopamine or medication wearing off. Insomnia, sleep apnea, restless legs, REM sleep behavior disorder, nocturia, pain, anxiety, medication effects, and blood-pressure changes may require different treatment. More carbidopa-levodopa will not necessarily correct them.

Keep a diary for several nights. Record the time of your last dose, bedtime, awakenings, stiffness, tremor, cramps, trouble turning, bathroom trips, falls or near-falls, morning symptoms, and vivid dreams or confusion. Also record when your morning dose begins working. This can help your neurologist decide whether nighttime coverage is needed.

Possible side effects include nausea, dizziness or low blood pressure when standing, involuntary movements, sleep disturbance, vivid dreams, confusion, and hallucinations. At night, dizziness or confusion can increase the risk of falling.

Do not add a bedtime dose, double a dose, change formulations, or stop carbidopa-levodopa suddenly on your own. Ask your neurologist: “Are my nighttime symptoms caused by wearing off, and would changing the timing or formulation of my carbidopa-levodopa help?” If you develop hallucinations, severe confusion, fainting, or major involuntary movements, contact your medical team promptly.

Disease progression can be part of the answer, but the real question is whether you have troublesome overnight symptoms that respond to carbidopa-levodopa and whether the likely benefit outweighs the risks for you. Best to you