An Overlooked Parkinson's Symptom: Hiccups

The most common, noticeable signs of Parkinson’s disease (PD) are motor symptoms, especially tremors. They affect about 70 percent of people with PD.¹

However, there are also many non-motor symptoms of PD. These include fatigue, loss of smell, and pain. At first glance, some of these symptoms may seem like an unrelated condition.

There is also one non-motor symptom that may be surprising: the hiccups.¹

What are hiccups?

Hiccups happen when the diaphragm – the muscle just below your lungs – uncontrollably contracts. When that happens, the vocal cords close. This causes the “hic” sound that gives hiccups their name.²

People with hiccups may also have a slight tightening feeling in their chest, abdomen, or throat.²

Carbonated drinks or large meals are the most common causes of hiccups. Other common causes include:^3,4

• Anxiety or stress
• Alcohol
• Spices
• Smoking or other irritants that bother the digestive or respiratory systems
• Drugs used to treat acid reflux

Hiccups can also be caused by damage in different parts of the brain, especially the brain stem.⁴

Are hiccups a sign of Parkinson’s disease?

Everyone has hiccups from time to time. They usually go away on their own within a few minutes. However, there are some types of hiccups that are often signs of underlying medical conditions. These types of hiccups include:³

• Persistent hiccups, or hiccups lasting longer than 2 days
• Intractable hiccups, or hiccups lasting more than 1 month

Research has found that persistent and intractable hiccups are more common in people with PD than those who do not have the disease. One study found that the rate of hiccups may be as much as 20 percent higher in people with PD than in healthy people.²

Some research shows that damage to the brain stem may be tied to an increase in hiccups in people with PD. This type of damage is common in people with PD.⁴

Some Parkinson’s treatments can cause hiccups

While hiccups can be a symptom of PD, they can also be a side effect of a type of drug that is often used to treat the disease.

Some studies have found that dopamine agonists drugs have caused hiccups in people with PD. This is a class of drugs that imitate the effect of dopamine when levels are low. Dopamine agonists are often prescribed to people with PD to help their brain think it is getting the dopamine it needs. This helps treat the motor symptoms of PD, like tremor, impaired balance, and rigidity.¹

There are many studies that show dopamine plays a large role in why hiccups occur. This may explain the tie between dopamine agonists and hiccups in people with PD.¹

How are hiccups treated in patients with Parkinson’s disease?

There is not much research about which drugs are safe to treat intractable hiccups in people with PD.

Many drugs that are often used to treat intractable hiccups are not recommended for people with PD. That is because these drugs can make motor symptoms like tremor worse. This makes treating intractable hiccups in people with PD more difficult.¹

When people with PD have intractable hiccups, there are some drugs doctors can use. These drugs treat the involuntary diaphragm spasms that cause hiccups. When intractable hiccups develop as a side effect of a dopamine agonist drug, a change in drugs often makes the hiccups stop.¹