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Syndros Side Effects

Generic name: dronabinol

Medically reviewed by Last updated on Sep 26, 2022.

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

Applies to dronabinol: oral capsule liquid filled, oral solution.

Serious side effects of Syndros

Along with its needed effects, dronabinol (the active ingredient contained in Syndros) 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 dronabinol:

Less common

  • Changes in mood
  • confusion
  • delusions
  • fast or pounding heartbeat
  • feelings of unreality
  • loss of memory
  • mental depression
  • nervousness or anxiety
  • problems with memory
  • seeing, hearing, or feeling things that are not there


  • Blurred vision
  • chills
  • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  • sweating
  • unusual tiredness or weakness

Incidence not known

  • Fainting
  • feeling of warmth
  • hives or rash
  • redness of the face, neck, arms, and occasionally, upper chest
  • seizures
  • sores in the mouth
  • swelling of the lips
  • tightness in the throat
  • trouble sleeping

Get emergency help immediately if any of the following symptoms of overdose occur while taking dronabinol:

Symptoms of overdose

  • Being forgetful
  • change in how fast you think time is passing
  • change in your sense of smell, taste, sight, sound, or touch
  • constipation
  • decrease in motor coordination
  • drowsiness (severe)
  • dryness of the mouth (severe)
  • false sense of well-being
  • feeling sluggish
  • panic reaction
  • problems in urinating
  • redness of the eyes
  • seizures
  • slurred speech
  • unusual drowsiness or dullness

Other side effects of Syndros

Some side effects of dronabinol 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:

More common

  • Clumsiness or unsteadiness
  • dizziness
  • drowsiness
  • false sense of well-being
  • nausea
  • trouble with thinking
  • vomiting

Less common or rare

  • Abdominal or stomach pain
  • flushing of the face
  • lack or loss of strength
  • restlessness


  • Burning, dry, or itching eyes
  • continuing ringing or buzzing or other unexplained noise in the ears
  • cough
  • diarrhea
  • discharge, excessive tearing
  • headache
  • hearing loss
  • redness, pain, swelling of the eye, eyelid, or inner lining of the eyelid
  • runny nose
  • sneezing
  • stuffy nose

For Healthcare Professionals

Applies to dronabinol: oral capsule, oral solution.


Very common (10% or more): Elation (up to 24%), feeling high/easy laughing (up to 24%), heightened awareness (up to 24%)

Common (1% to 10%): Abnormal thinking, euphoria, paranoid reaction

Frequency not reported: Anxiety/nervousness, confusion, depersonalization, depression, hallucinations, nightmares

Postmarketing reports: Delirium, disorientation, insomnia, panic attack[Ref]


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

Frequency not reported: Diarrhea, fecal incontinence

Postmarketing reports: Lip swelling, oral lesions[Ref]

Nervous system

Common (1% to 10%): Dizziness, somnolence

Frequency not reported: Amnesia, ataxia, headache, speech difficulties

Postmarketing reports: Fatigue, loss of consciousness, movement disorder, seizure/seizure-like activity, syncope[Ref]


Frequency not reported: Flushing, hypotension, palpitations, tachycardia, vasodilation/facial flush[Ref]


Frequency not reported: Asthenia, chills, malaise, tinnitus

Postmarketing reports: Fall, fatigue[Ref]


Frequency not reported: Cough, rhinitis, sinusitis

Postmarketing reports: Throat tightness[Ref]


Frequency not reported: Conjunctival injection, vision difficulties[Ref]


Frequency not reported: Sweating

Postmarketing reports: Disseminated rash, hives, skin burning[Ref]


Frequency not reported: Hepatic enzyme elevation[Ref]


Frequency not reported: Myalgia[Ref]


Frequency not reported: Anorexia[Ref]

Frequently asked questions


1. "Product Information. Marinol (dronabinol)." Roxane Laboratories Inc (2001):

2. "Product Information. Syndros (dronabinol)." Insys Therapeutics Inc (2017):

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.