Nuedexta Side Effects

Generic name: dextromethorphan / quinidine

Medically reviewed by Drugs.com. Last updated on Oct 20, 2023.

Note: This document contains side effect information about dextromethorphan / quinidine. Some dosage forms listed on this page may not apply to the brand name Nuedexta.

Applies to dextromethorphan / quinidine: oral capsule.

Serious side effects of Nuedexta

Along with its needed effects, dextromethorphan/quinidine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking dextromethorphan / quinidine:

Less common

Bladder pain
bloating or swelling of the face, arms, hands, lower legs, or feet
bloody or cloudy urine
chills
cough
diarrhea
difficult, burning, or painful urination
fever
frequent urge to urinate
general feeling of discomfort or illness
headache
joint pain
loss of appetite
lower back or side pain
muscle aches and pains
nausea
rapid weight gain
runny nose
shivering
sore throat
sweating
tingling of the hands or feet
trouble sleeping
unusual tiredness or weakness
unusual weight gain or loss
vomiting

Get emergency help immediately if any of the following symptoms of overdose occur while taking dextromethorphan / quinidine:

Symptoms of overdose

Aggressive and violent behavior
agitation
blurred vision
change in color vision
change in consciousness
chest pain or discomfort
confusion
confusion as to time, place, or person
continuing ringing or buzzing or other unexplained noise in the ears
decreased awareness or responsiveness
depression
difficulty seeing at night
dizziness or lightheadedness
dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
double vision
excitement
fainting
fast, pounding, or irregular heartbeat or pulse
feeling of constant movement of self or surroundings
hallucinations
hearing loss
holding false beliefs that cannot be changed by fact
inability to move the eyes
increased blinking or spasms of the eyelid
increased sensitivity of the eyes to sunlight
irregular or slow heart rate
loss of consciousness
overactive reflexes
poor coordination
restlessness
seeing double
seizures
sensation of spinning
severe sleepiness
shakiness and unsteady walk
shivering
shortness of breath
sticking out of tongue
sweating
talking or acting with excitement you cannot control
trembling or shaking
trouble with breathing, speaking, or swallowing
twitching
uncontrolled eye movements
uncontrolled twisting movements of the neck, trunk, arms, or legs
unsteadiness, trembling, or other problems with muscle control or coordination
unusual excitement, nervousness, or restlessness
unusual facial expressions

Other side effects of Nuedexta

Some side effects of dextromethorphan / quinidine may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common

Bloated
excess air or gas in the stomach or intestines
full feeling
lack or loss of strength
passing gas

For Healthcare Professionals

Applies to dextromethorphan / quinidine: oral capsule.

General

The most commonly reported adverse reactions (2% or greater incidence and greater than placebo) that led to treatment discontinuation were muscle spasticity, abdominal pain, asthenia, dizziness, muscle spasms, respiratory failure, and fall.^[Ref]

Gastrointestinal

Very common (10% or more): Diarrhea (13%)

Common (1% to 10%): Abdominal pain, vomiting, flatulence

Dextromethorphan:

Postmarketing reports: Nausea, vomiting, stomach pain^[Ref]

Nervous system

Very common (10% or more): Dizziness (10%)

Dextromethorphan:

Postmarketing reports: Drowsiness, dizziness, nervousness, restlessness

Quinidine:

Postmarketing reports: Convulsions, apprehension, ataxia, acute psychotic reactions (rare)^[Ref]

Cardiovascular

Frequency not reported: QTc prolongation^[Ref]

Musculoskeletal

Common (1% to 10%): Muscle spasticity, muscle spasms^[Ref]

Hepatic

Common (1% to 10%): Increased gamma-glutamyltransferase^[Ref]

Respiratory

Common (1% to 10%): Respiratory failure, cough^[Ref]

Other

Common (1% to 10%): Asthenia, fall, peripheral edema

Quinidine:

Postmarketing reports: Cinchonism^[Ref]

Cinchonism is usually a sign of chronic quinidine toxicity, but it may appear in sensitive patients after a single moderate dose of several hundred milligrams. It is characterized by nausea, vomiting, diarrhea, tinnitus headache, hearing loss, vertigo, blurred vision, diplopia, photophobia, confusion, and delirium.^[Ref]

Immunologic

Common (1% to 10%): Influenza^[Ref]

Genitourinary

Common (1% to 10%): Urinary tract infection^[Ref]

Ocular

Quinidine:

Postmarketing reports: Mydriasis, disturbed color perception, night blindness, scotomata, optic neuritis, visual field loss, photosensitivity, keratopathy^[Ref]