Last updated on RxList: 4/1/2021
Syndros Side Effects Center

Medical Editor: John P. Cunha, DO, FACOEP

What Is Syndros?

Syndros (dronabinol) oral solution is a cannabinoid indicated in adults for the treatment of anorexia associated with weight loss in patients with AIDS, and nausea and vomiting associated with cancer chemotherapy in patients who have failed to respond adequately to conventional antiemetic treatments.

What Are Side Effects of Syndros?

Common side effects of Syndros include:

  • dizziness
  • euphoria
  • paranoid reaction
  • drowsiness
  • abnormal thinking
  • abdominal pain
  • nausea
  • vomiting
  • weakness
  • palpitations
  • fast heart rate
  • flushing
  • amnesia
  • anxiety or nervousness
  • problems with coordination
  • confusion, or
  • feeling detached from your thoughts or body (depersonalization)

Less common side effects of Syndros include:

Dosage for Syndros

The calibrated oral syringe measures a maximum Syndros dose of 5 mg. If the prescribed dose is greater than 5 mg, the total dose of Syndros will need to be divided and drawn up in two or more portions using the oral syringe. Take Syndros with a full glass of water (6 to 8 ounces).

What Drugs, Substances, or Supplements Interact with Syndros?

Syndros may interact with disulfiram, metronidazole, amiodarone, azole antifungals, clarithromycin, ritonavir, erythromycin, grapefruit juice, warfarin, cyclosporine, and amphotericin B. Tell your doctor all medications and supplements you use. Syndros is not recommended for use during pregnancy; it may harm a fetus. Consult your doctor before breastfeeding.

Syndros During Pregnancy and Breastfeeding

HIV infected women are advised not to breastfeed and women with nausea and vomiting associated with cancer chemotherapy are advised not to breastfeed during treatment with Syndros and for 9 days after the last dose. Withdrawal symptoms may occur if you suddenly stop taking Syndros.

Additional Information

Our Syndros (dronabinol) oral solution Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Syndros Consumer Information

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Get emergency medical help if you have signs of an allergic reaction: hives, skin rash or burning; mouth sores; warmth, redness, or tingly feeling; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

  • a seizure;
  • fast or pounding heartbeats;
  • a light-headed feeling, like you might pass out;
  • confusion, trouble sleeping, problems with memory or concentration;
  • unusual changes in mood or behavior;
  • restlessness, feeling nervous or irritable;
  • slurred speech, drowsiness;
  • severe or ongoing nausea, vomiting, or stomach pain; or
  • increased blood pressure--severe headache, blurred vision, pounding in your neck or ears.

Common side effects may include:

  • feeling "high";
  • dizziness, drowsiness, thinking problems;
  • unusual thoughts or fears;
  • feelings of extreme happiness; or
  • nausea, vomiting, stomach pain.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Read the entire detailed patient monograph for Syndros ( C-X Dronabinol Oral Solution)

Syndros Professional Information


Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

The following serious adverse reactions are described below and elsewhere in the labeling.

  • Neuropsychiatric Adverse Reactions [see WARNINGS AND PRECAUTIONS]
  • Hemodynamic Instability [see WARNINGS AND PRECAUTIONS]
  • Paradoxical Nausea, Vomiting, and Abdominal Pain [see WARNINGS AND PRECAUTIONS]
  • Toxicity in Preterm Neonates [see WARNINGS AND PRECAUTIONS]

The safety of SYNDROS has been established based on studies of dronabinol capsules. Studies of AIDS-related weight loss included 157 patients receiving dronabinol capsules and 67 receiving placebo. Studies of nausea and vomiting related to cancer chemotherapy included 317 patients receiving dronabinol capsules and 68 receiving placebo. In the tables below is a summary of the adverse reactions in 474 patients exposed to dronabinol capsules in studies.

Studies of different durations were combined by considering the first occurrence of adverse reactions during the first 28 days.

A cannabinoid dose-related “high” (easy laughing, elation and heightened awareness) has been reported by patients receiving dronabinol capsules in both the antiemetic (24%) and the lower dose appetite stimulant clinical trials (8%). The most frequently reported adverse experiences in patients with AIDS during placebo-controlled clinical trials involved the CNS and were reported by 33% of patients receiving dronabinol capsules. About 25% of patients reported a CNS adverse reaction during the first 2 weeks and about 4% reported such a reaction each week for the next 6 weeks thereafter.

Common Adverse Reactions

The following adverse reactions were reported in clinical trials of dronabinol capsules at an incidence greater than 1%.

System Organ Class Adverse Reactions
General Asthenia
Cardiovascular Palpitations, tachycardia, vasodilation/facial flush
Gastrointestinal Abdominal pain*, nausea*, vomiting*
Central Nervous System Dizziness*, euphoria*, paranoid reaction*, somnolence*, thinking abnormal*, amnesia, anxiety/nervousness, ataxia, confusion, depersonalization, hallucination
*Actual Incidence 3% to 10%

Less Common Adverse Reactions

The following adverse reactions were reported in clinical trials of dronabinol capsules at an incidence less than or equal to 1%.

System Organ Class Adverse Reactions
General Chills, headache, malaise
Cardiovascular Hypotension, conjunctival injection [see CLINICAL PHARMACOLOGY]
Gastrointestinal Diarrhea, fecal incontinence, anorexia, hepatic enzyme elevation
Musculoskeletal Myalgias
Central Nervous System Depression, nightmares, speech difficulties, tinnitus
Respiratory Cough, rhinitis, sinusitis
Skin Flushing, sweating
Sensory Vision difficulties

Postmarketing Experience

The following adverse reactions have been identified during post-approval use of another oral formulation of dronabinol. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

General disorders and administration site conditions: fatigue.

Hypersensitivity reactions: lip swelling, hives, disseminated rash, oral lesions, skin burning, flushing, throat tightness [see CONTRAINDICATIONS].

Injury, poisoning and procedural complications: fall [see Use In Specific Populations].

Nervous system disorders: seizures [see WARNINGS AND PRECAUTIONS], disorientation, movement disorder, loss of consciousness.

Psychiatric disorders: delirium, insomnia, panic attack.

Vascular disorders: syncope [see WARNINGS AND PRECAUTIONS].


Disulfiram And Metronidazole

SYNDROS contains 50% (w/w) dehydrated alcohol and 5.5% (w/w) propylene glycol, which can produce disulfiram-like reactions when co-administered with disulfiram or other drugs that produce this reaction (e.g., metronidazole). Discontinue products containing disulfiram or metronidazole at least 14 days before starting treatment with SYNDROS and do not administer these products within 7 days of completing treatment with SYNDROS [see CONTRAINDICATIONS, WARNINGS AND PRECAUTIONS].

When administered concomitantly with propylene glycol, ethanol competitively inhibits the metabolism of propylene glycol, which may lead to elevated concentrations of propylene glycol. However, the contribution of propylene glycol, if any, to the interaction between disulfiram and SYNDROS is unknown.

Effect Of Other Drugs On Dronabinol

Dronabinol is primarily metabolized by CYP2C9 and CYP3A4 enzymes. Inhibitors of these enzymes may increase, while inducers may decrease, the systemic exposure of dronabinol and/or its active metabolite resulting in an increase in dronabinol-related adverse reactions or loss of efficacy of SYNDROS.

Monitor for increased dronabinol-related adverse reactions when SYNDROS is co-administered with inhibitors of CYP2C9 (e.g., amiodarone, fluconazole) and inhibitors of CYP3A4 enzymes (e.g., ketoconazole, itraconazole, clarithromycin, ritonavir, erythromycin, grapefruit juice).

Highly Protein-Bound Drugs

Dronabinol is highly bound to plasma proteins, and therefore, might displace and increase the free fraction of other concomitantly administered protein-bound drugs. Although this displacement has not been confirmed in vivo, monitor patients for increased adverse reactions to narrow therapeutic index drugs (e.g., warfarin, cyclosporine, amphotericin B) when initiating treatment or increasing the dosage of SYNDROS.

Read the entire FDA prescribing information for Syndros ( C-X Dronabinol Oral Solution)

© Syndros Patient Information is supplied by Cerner Multum, Inc. and Syndros Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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