Hiccups, known medically as singultus, are involuntary spasms of the diaphragm, the dome-shaped muscle located beneath the lungs that controls breathing. The spasm is followed immediately by the rapid closure of the vocal cords, which produces the characteristic “hic” sound. While a brief episode of hiccups is common, for people undergoing cancer treatment, these spasms can become persistent and highly distressing. When hiccups are a side effect of chemotherapy or related supportive medications, they can interfere with eating, sleeping, and talking, significantly impacting a patient’s overall quality of life. Managing them requires a partnership with the oncology care team.
Immediate Self-Care Techniques
Initial attempts to stop hiccups should focus on non-pharmacological methods that can be performed at home, which aim to interrupt the reflex arc controlling the spasm. The hiccup reflex involves the vagus and phrenic nerves, and simple physical maneuvers can stimulate these pathways to reset normal diaphragm function. These low-risk interventions are worth trying immediately.
One common method involves manipulating the respiratory cycle to increase the carbon dioxide level in the blood, which can help relax the diaphragm. This can be achieved by taking a deep breath and holding it for as long as comfortable, repeating this process several times. Similarly, the Valsalva maneuver involves exhaling forcefully against closed airways, such as pinching the nose and closing the mouth, which exerts pressure on the vagus nerve.
Stimulating the vagus nerve directly can also disrupt the hiccup reflex and is the principle behind many traditional remedies. Swallowing a spoonful of granulated sugar or gargling with ice-cold water irritates the back of the throat, which sends signals through the vagus nerve. Another technique involves drinking water quickly, sometimes from the far side of a glass while bending over, which requires a change in posture and pressure that can also stimulate the nerve.
Pharmacological Management
When self-care techniques fail to resolve hiccups that have become prolonged or severe, prescription medications are often necessary to provide definitive relief. These drugs target the nerve pathways responsible for the hiccup reflex arc and must only be started under the guidance of a physician. The choice of medication depends on the patient’s overall health status and potential interactions with their chemotherapy regimen.
Muscle relaxants are a common class of drugs utilized, with baclofen often prescribed to calm the involuntary spasm of the diaphragm. Baclofen works centrally to inhibit nerve signals, which helps to suppress the erratic contractions. Another effective option is the anti-convulsant drug gabapentin, which has shown promise in treating persistent hiccups by affecting nerve transmission in the central nervous system.
Anti-dopaminergic agents, such as metoclopramide or chlorpromazine, are also frequently used to manage severe cases. Chlorpromazine is the only medication approved by the U.S. Food and Drug Administration specifically for intractable hiccups. If gastric reflux is suspected as a contributing factor, proton pump inhibitors may be added to the treatment plan to reduce stomach acid irritation.
Understanding the Underlying Causes
Understanding why hiccups occur frequently during cancer treatment can help inform the most effective treatment approach. The hiccup is triggered by irritation to the nerve pathways, primarily the phrenic nerve controlling the diaphragm and the vagus nerve. In the context of chemotherapy, the causes are often medication-related, rather than the cancer itself.
The most common culprit is a class of supportive care medications called corticosteroids, particularly dexamethasone, which is widely used to prevent nausea and vomiting associated with chemotherapy. Dexamethasone is strongly linked to hiccups, likely because of its ability to cross the blood-brain barrier and potentially affect the nerve center that controls the hiccup reflex. In some cases, simply withholding or changing the antiemetic steroid can resolve the hiccups entirely.
Certain chemotherapy drugs, such as cisplatin and oxaliplatin, are also known to cause hiccups. Furthermore, a tumor pressing on the diaphragm, phrenic nerve, or vagus nerve in the chest or abdomen can directly trigger the persistent spasms. Other factors, like electrolyte imbalances or gastric distension, can also contribute to the irritation of these nerves.
When to Contact Your Oncology Team
While brief hiccups are generally harmless, persistent episodes in a patient undergoing chemotherapy must be reported to the oncology team without delay. The threshold for concern is reached when hiccups last longer than 48 hours, at which point they are classified as persistent and are less likely to resolve on their own. This duration signals a need for medical evaluation to determine the underlying cause and initiate prescription treatment.
A prompt call to the care team is also warranted if the hiccups begin to interfere significantly with essential daily functions. This includes difficulty eating, which can lead to malnutrition and dehydration, or interference with sleep, which causes profound fatigue and exhaustion. These issues are serious concerns for cancer patients whose bodies are already under strain from treatment.
Additional symptoms accompanying the hiccups also necessitate immediate medical attention. These symptoms can include chest pain, fever, trouble breathing, or persistent vomiting, which may suggest a more serious underlying issue or complication. Ignoring persistent hiccups can lead to complications such as aspiration, so the oncology team must be informed quickly.