What Is a Phrenic Nerve Block for Chronic Hiccups?

A phrenic nerve block is a rare, off-label medical procedure occasionally considered for chronic hiccups (hiccups lasting more than 48 hours or weeks) when standard treatments have failed ^{[1] [2]}. The procedure involves injecting a local anesthetic (numbing medication) near the phrenic nerve in your neck ^[3]. The goal is to temporarily interrupt the signals telling your diaphragm to spasm, offering a potential break from the exhaustion of constant hiccups ^[1].

It is important to understand that a phrenic nerve block is an investigational, symptom-management approach—not a guaranteed cure ^[1]. Because it intentionally weakens the muscle that controls your breathing, it is only considered by specialists in exceptional cases after careful evaluation ^[4].

Evaluating the Root Cause First

Chronic hiccups are a symptom, not a disease themselves. The hiccup reflex involves a complex pathway in the body, and persistent hiccups can be triggered by medication side effects, severe acid reflux, metabolic or electrolyte imbalances, gastrointestinal diseases, or neurological issues ^{[1] [2]}.

Before considering a nerve block, your medical team should thoroughly investigate and treat these potential underlying causes. Because living with chronic hiccups can cause severe sleep deprivation, dangerous weight loss, and severe depression, addressing hydration, nutrition, and mental health is just as urgent as stopping the spasms. If the physical and emotional toll of chronic hiccups leads to thoughts of self-harm, please seek emergency mental health support immediately.

How the Procedure Works

The phrenic nerve carries motor signals from your neck down to your diaphragm (the main breathing muscle under your lungs). By injecting a local anesthetic around this nerve, doctors aim to temporarily block those signals, which stops or reduces the diaphragm contractions ^{[3] [5]}.

The block does not “reset” the nerve or cure the underlying trigger of the hiccup reflex ^[1]. While some patients experience relief that outlasts the numbing medication, the exact reason for this prolonged relief is uncertain, and it cannot be relied upon ^[1].

Reported Outcomes

There are no large clinical trials for this procedure in hiccup treatment. The evidence comes almost entirely from isolated case reports and very small series, meaning reliable success rates are unknown ^{[1] [6]}. Based on these reports, outcomes are highly unpredictable:

• Prolonged relief: A few reported cases describe relief lasting weeks after a single injection ^{[5] [6]}.
• Brief relief: Other patients only experience relief for a few hours until the anesthetic wears off ^[7].
• No benefit or worsening: Some patients experience no relief at all, and in rare cases, the procedure can temporarily worsen the spasms ^[1].

If the block fails, your doctor may suggest other specialist options, such as pulsed radiofrequency (using energy to modify nerve signaling), though this is an even less established experimental option with its own uncertain risks ^[6].

What to Expect on the Day

A phrenic nerve block is usually performed in a specialized pain clinic or hospital setting where your breathing can be monitored.

1. Preparation: You will likely remain awake, though a mild sedative may be offered for anxiety. A local anesthetic is used to numb the skin on your neck.
2. The Injection: The specialist will use an ultrasound machine to identify the tiny phrenic nerve (usually around the lower neck) ^[3]. Ultrasound allows them to see the needle in real time, avoiding blood vessels and the lungs ^{[8] [9]}. They will inject the anesthetic, sometimes mixed with a corticosteroid, on one side of your neck ^{[3] [5]}. Treating both sides simultaneously is generally avoided due to the severe risk of paralyzing both sides of the diaphragm at once ^[10].
3. Observation: You will be monitored for a period of time to ensure your breathing remains stable and your oxygen levels are safe ^[4]. You will need a designated driver to take you home.

Risks and Respiratory Assessment

Because a phrenic nerve block temporarily paralyzes or weakens one side of your diaphragm, breathing impairment is the most significant risk ^[4].

Before agreeing to this procedure, your doctor must assess your individual respiratory reserve ^{[11] [12]}. Patients with chronic obstructive pulmonary disease (COPD), sleep apnea, obesity, heart disease, or pre-existing weakness in the opposite diaphragm are at a much higher risk for dangerous breathing complications ^{[12] [11]}. Your doctor may use tests like point-of-care ultrasound or pulmonary function tests to evaluate your diaphragm function beforehand ^[11].

While ultrasound guidance lowers the chances of technical complications, it does not eliminate them ^{[9] [13]}. Other potential risks include:

• Accidental puncture of the lung (pneumothorax) ^[8].
• Bleeding or accidental injection into a blood vessel ^[8].
• Nerve injury resulting in prolonged or permanent diaphragm dysfunction ^[13].
• Local anesthetic toxicity or allergic reaction ^[13].
• Unintended numbing of nearby nerves, temporarily causing hoarseness, difficulty swallowing, or weakness in nearby muscles.

When to Seek Urgent Care

Because breathing complications can arise after you leave the clinic, you must have a plan in place. Seek emergency medical care immediately if you experience any of the following after a phrenic nerve block:

• New or worsening shortness of breath
• Blue tint to your lips or fingertips
• Chest pain
• Fainting or severe dizziness
• Markedly low oxygen readings (if using a home monitor)
• Severe neck swelling or uncontrolled bleeding at the injection site
• New difficulty speaking normally or swallowing