What drug do they give you before an MRI?

October 5, 2025 •

4 min read

While most people undergo an MRI without any medication, millions of patients receive specific drugs to ensure the procedure is successful. Understanding what drug do they give you before an MRI depends on whether the goal is to manage anxiety or to enhance the diagnostic images.

Quick Summary

Depending on patient needs, a physician may administer a sedative like a benzodiazepine to help with anxiety or claustrophobia during an MRI, or an intravenous contrast agent such as gadolinium to improve image clarity. Medication is used to ensure patient comfort and high-quality diagnostic results, with options ranging from oral anxiolytics to IV conscious sedation.

Key Points

Sedatives for Anxiety: Medications like benzodiazepines (e.g., Xanax, Ativan) are used to relax anxious or claustrophobic patients.
IV Conscious Sedation: For severe cases, an IV drip may deliver a combination of sedatives and analgesics (e.g., Midazolam, Fentanyl) to ensure stillness.
Contrast Agents: Gadolinium-based agents (GBCAs) are injected intravenously to enhance image visibility, helping to diagnose conditions like tumors or inflammation.
Kidney Function Check: Kidney function is assessed before giving a gadolinium contrast agent, as it is eliminated by the kidneys.
Fast Acting Sedatives: Short-acting agents like Propofol or Midazolam are preferred for IV sedation to ensure a fast recovery.
Preparation is Key: Patients receiving sedatives must fast before the exam and arrange for transportation home afterward.
Specific Indications: Sedation is not routine and is reserved for patients who cannot remain still, such as young children or those with severe anxiety.
Allergic Reactions: Severe allergic reactions to gadolinium are extremely rare, but radiology departments are prepared to handle them.

A magnetic resonance imaging (MRI) scan is a safe and painless procedure, but it can be challenging for some patients due to the need to lie still in a narrow, enclosed space for an extended period. For this reason, and to enhance the diagnostic quality of the images, certain medications may be administered before or during the exam. These can be broadly categorized into sedatives for patient comfort and contrast agents for improved image visualization.

Sedatives for anxiety and claustrophobia

Sedation is often used for patients who experience severe anxiety, claustrophobia, or have difficulty remaining still duee to pain or involuntary movements. Medications are chosen based on the patient's anxiety level, health history, and the MRI facility's protocols.

Oral benzodiazepines

For moderate anxiety or mild claustrophobia, a doctor might prescribe an oral benzodiazepine to be taken prior to the exam. These drugs work by enhancing the effects of a neurotransmitter called GABA, which suppresses nerve activity and induces a calming effect.

Common oral benzodiazepines include:

Alprazolam (Xanax): A short-acting benzodiazepine used to treat anxiety and panic disorders.
Lorazepam (Ativan): Another benzodiazepine that can relieve anxiety and relax muscles.
Diazepam (Valium): A longer-acting option that can provide a calming effect throughout the duration of the scan.

Intravenous (IV) conscious sedation

In cases of severe claustrophobia, extreme anxiety, or for young children and patients unable to cooperate, IV conscious sedation may be necessary. This type of sedation is administered in a hospital or specialized facility with a board-certified anesthesiologist present to monitor the patient's vital signs throughout the procedure.

IV conscious sedation often involves a combination of medications, such as:

Midazolam (Versed): A fast-acting benzodiazepine that causes drowsiness, relaxation, and anterograde amnesia, which means the patient may not remember much of the procedure.
Fentanyl: A potent opioid medication used for its analgesic and sedative properties, often used in conjunction with a benzodiazepine.
Propofol: A powerful sedative and anesthetic agent with a rapid onset and quick recovery time, making it ideal for procedures requiring deep sedation.

Contrast agents for enhanced imaging

In many cases, an MRI requires a contrast agent, often referred to as 'contrast dye,' to enhance the clarity of the images. This allows radiologists to see blood vessels, tumors, inflammation, and other abnormalities more distinctly.

Gadolinium-based contrast agents (GBCAs)

The most common type of contrast agent used in MRI contains gadolinium, a rare-earth metal. To make it safe for intravenous injection, the gadolinium is chelated, or bonded, to a carrier molecule. These agents work by altering the magnetic properties of water molecules in the body, which improves image quality.

Examples of GBCAs include:

Gadobutrol (Gadavist): A macrocyclic agent known for its stability.
Gadoterate meglumine (Dotarem): Another stable macrocyclic agent commonly used.
Gadoxetate disodium (Eovist): Primarily used for liver imaging.

GBCAs are mostly eliminated from the body via the kidneys within 24 hours in patients with normal renal function. However, small amounts can be retained in the body long-term. For patients with severe kidney disease, there is a risk of a rare condition called nephrogenic systemic fibrosis (NSF). Therefore, kidney function is always checked before a GBCA is administered.

Comparison of medication types


Feature	Sedatives (Benzodiazepines/IV)	Contrast Agents (GBCAs)
Primary Purpose	To calm the patient, reduce anxiety, and ensure they remain still for a clear scan.	To improve the visibility and detail of internal body structures on the MRI images.
Administration	Oral tablet taken beforehand or IV injection administered by an anesthesiologist or nurse.	Intravenous injection into a vein in the arm, typically during the scan.
Primary Target	The central nervous system to induce relaxation and sleepiness.	Tissues and blood vessels to enhance the magnetic signals captured by the MRI.
Patient Preparation	May require fasting for a period before the exam and arranging for a ride home.	Requires a check of kidney function (creatinine level) to ensure safe elimination.
Side Effects	Drowsiness, dizziness, memory impairment. IV sedation requires careful monitoring.	Cool sensation at injection site, nausea, headache. Severe allergic reactions are rare.
Key Risk	Dependence with prolonged use, respiratory depression with IV sedation.	Rare risk of NSF in patients with severe kidney disease; small amounts of gadolinium retention.

Conclusion

An MRI is a powerful diagnostic tool, and the use of specific medications can be a crucial part of a successful scan. For patients struggling with anxiety or claustrophobia, oral or intravenous sedatives can provide the necessary comfort to complete the procedure. Meanwhile, gadolinium-based contrast agents are vital for improving the clarity of images, enabling a more accurate diagnosis. The decision to use any medication is always made on a case-by-case basis, with the medical team weighing the benefits against potential risks, ensuring the safest and most effective outcome for the patient. Communicating any anxieties or medical conditions to your doctor beforehand is the most important step in preparing for an MRI with medication.

Other medications and considerations

Beyond sedatives and contrast agents, other medications and patient-specific factors are considered. For example, some facilities use wide-bore MRI machines or offer distraction techniques, such as music or mirrors, to help patients cope with confinement. Additionally, in very rare cases of severe allergies to contrast media, a steroid premedication regimen may be given, though this is uncommon. The specific needs of children, patients with neurodevelopmental disorders like autism, and those with sleep apnea also require careful consideration and specialized sedation protocols. In all cases, a thorough medical history and evaluation are essential to determine the best approach for each individual.

Frequently Asked Questions

The most common drugs for MRI anxiety are oral benzodiazepines such as lorazepam (Ativan), alprazolam (Xanax), or diazepam (Valium). These are prescribed by your doctor beforehand and are not kept on hand at the imaging facility.

No, gadolinium contrast and sedation are different types of medication. Gadolinium is a contrast agent injected intravenously to enhance the visibility of internal structures on the MRI image. Sedatives are used to help patients relax or fall asleep for the procedure.

In most cases, no. Mild to moderate sedation with oral medication or IV conscious sedation is used to make you drowsy and relaxed. Complete general anesthesia is typically reserved for young children, patients with severe medical issues, or those requiring deep sedation, and is administered by an anesthesiologist.

If you are receiving IV sedation, yes, you will typically need to fast for a set period (usually 6 to 8 hours) before the scan to reduce the risk of complications. Specific instructions will be provided by your medical team.

Common side effects are usually mild and may include a cold sensation at the injection site, nausea, or a headache. Severe allergic reactions are extremely rare, but facilities are equipped to manage them.

The duration depends on the medication used. Fast-acting IV sedatives like midazolam have a rapid recovery time, with most patients alert within 30-45 minutes after the scan. Oral medications may have longer-lasting effects.

No. If you receive any sedative medication, you must arrange for a responsible adult to drive you home. You should not operate a vehicle or heavy machinery for the remainder of the day.

Kidney function is crucial when using gadolinium contrast agents because the kidneys are responsible for flushing the medication out of the body. In patients with severe kidney disease, a rare complication called nephrogenic systemic fibrosis (NSF) can occur, so kidney function is always screened before administration.