What to Know About Marinol Side Effects Before You Start

If your doctor has prescribed Marinol (Dronabinol), you're probably wondering what side effects to expect. Like all medications, Marinol comes with potential side effects — some mild and manageable, others that need immediate medical attention.

This guide covers the most common side effects, the serious ones to watch for, and practical tips for managing them. Knowing what's normal and what's not can help you feel more confident about your treatment.

What Is Marinol?

Marinol is the brand name for Dronabinol, a synthetic form of THC (delta-9-tetrahydrocannabinol). It's FDA-approved for two conditions: appetite loss and weight loss in patients with AIDS, and nausea and vomiting caused by chemotherapy when other treatments haven't worked. For more details, see our complete guide: What Is Marinol?

Common Side Effects

Most people who take Marinol will experience at least some mild side effects, especially when starting the medication or after a dose increase. These usually improve as your body adjusts.

Dizziness

This is one of the most frequently reported side effects. You may feel lightheaded or unsteady, especially when standing up quickly. Avoid driving or operating heavy machinery until you know how Marinol affects you.

Drowsiness

Marinol can make you sleepy. This effect is stronger when combined with other medications that cause drowsiness, such as benzodiazepines, opioids, or antihistamines. Learn more about these combinations in our drug interactions guide.

Euphoria

Because Dronabinol is synthetic THC, some people experience a "high" feeling. This is more common at higher doses. If the euphoria is uncomfortable or interferes with your daily life, let your doctor know — they may lower your dose.

Nausea and Abdominal Pain

Ironically, a drug used to treat nausea can sometimes cause it. Stomach discomfort and abdominal pain are reported by some patients. Taking Marinol with food may help.

Abnormal Thinking

Some people notice changes in how they think or process information. This might include difficulty concentrating, confusion, or feeling "foggy." This effect is usually dose-related.

Serious Side Effects — When to Call Your Doctor

While most side effects are mild, some require immediate medical attention. Contact your doctor or go to the emergency room if you experience any of the following:

Psychiatric Reactions

Marinol can cause significant psychiatric effects in some people, including:

• Paranoia — feeling that others are watching or trying to harm you
• Hallucinations — seeing or hearing things that aren't there
• Panic attacks — sudden, intense fear with physical symptoms like racing heart and shortness of breath
• Psychosis — losing touch with reality

These reactions are more common in patients with a history of psychiatric illness, but they can happen to anyone. If you experience any of these, stop taking Marinol and call your doctor immediately.

Heart and Blood Pressure Changes

Marinol can affect your cardiovascular system. Watch for:

• Rapid heartbeat (tachycardia)
• Sudden drops in blood pressure when standing (orthostatic hypotension)
• Fainting or near-fainting episodes

These effects are especially concerning for people with existing heart conditions.

Seizures

Though rare, seizures have been reported with Dronabinol use. If you have a seizure or a history of seizure disorders, contact your doctor right away.

Severe Nausea or Vomiting

Paradoxical nausea and vomiting — the very symptoms Marinol is meant to treat — can sometimes get worse. If your nausea becomes severe or uncontrollable, your doctor may need to adjust your treatment.

Side Effects in Specific Populations

Older Adults

Elderly patients tend to be more sensitive to the psychoactive effects of Marinol. Dizziness, confusion, and falls are more common in this group. Doctors usually start with the lowest possible dose.

People With a History of Substance Use

Because Dronabinol is synthetic THC, there's a risk of abuse and dependence. If you have a history of substance use disorder, your doctor will monitor you more closely.

People With Psychiatric Conditions

If you have a history of depression, anxiety, bipolar disorder, or schizophrenia, Marinol may worsen your symptoms. Your doctor should weigh the benefits against the risks before prescribing.

Pregnant or Breastfeeding Women

Marinol is not recommended during pregnancy or breastfeeding. THC can pass to the baby through breast milk.

Patients With Sesame Allergy

Marinol capsules contain sesame oil. If you have a sesame allergy, this formulation is not safe for you. Talk to your doctor about the oral solution (Syndros) or other alternatives.

How to Manage Side Effects

Here are practical strategies that can help reduce the impact of Marinol's side effects:

• Start low, go slow. Most doctors begin with 2.5 mg twice daily and increase gradually. This gives your body time to adjust.
• Take it with food. Eating before or with your dose can help reduce nausea and stomach discomfort.
• Avoid alcohol. Alcohol increases drowsiness and dizziness. It can also worsen psychiatric side effects.
• Stay hydrated. Drink plenty of water throughout the day.
• Don't drive until you know how it affects you. Wait several days after starting or increasing your dose before getting behind the wheel.
• Keep a side effect journal. Write down what you experience and when. This helps your doctor make informed dosing decisions.
• Never stop suddenly. Abruptly stopping Marinol can cause withdrawal symptoms like irritability, insomnia, and restlessness. Always taper under your doctor's supervision.

Final Thoughts

Marinol can be an effective treatment for appetite loss and chemotherapy-related nausea, but it's important to go in with your eyes open about potential side effects. Most common side effects are manageable and improve over time. Serious reactions are less common but need immediate attention.

Talk to your doctor before starting Marinol, report any new or unusual symptoms promptly, and never adjust your dose on your own. If you're looking for more information about this medication, check out our guides on how Marinol works and how to find a prescribing doctor.