What is the prevalence of hiccups after a subcutaneous (SC) or intramuscular (IM) injection?

Prevalence of Hiccups After Subcutaneous or Intramuscular Injection

There is no established prevalence rate of hiccups following subcutaneous (SC) or intramuscular (IM) injections in the medical literature, as this appears to be a rare and underreported adverse effect.

Mechanism and Pathophysiology

Hiccups (singultus) result from a reflex arc involving:

• Peripheral phrenic, vagal, and sympathetic nerve pathways
• Central midbrain modulation
• Sudden diaphragmatic and intercostal muscle contraction followed by laryngeal closure 1

While hiccups following injections are not well documented in guidelines, understanding the potential mechanisms is important:

1. Medication-induced hiccups: Certain medications administered via injection can trigger hiccups, though this is more commonly reported with:

   • Corticosteroids (particularly systemic administration) 2
   • Anesthetic agents 1
   • Some antibiotics 3

2. Procedural factors: The physical act of injection may occasionally:

   • Irritate nerve pathways involved in the hiccup reflex arc
   • Cause transient diaphragmatic stimulation
   • Create localized inflammation that affects nearby neural structures

Documented Cases of Injection-Related Hiccups

The available evidence suggests injection-related hiccups are rare but documented in specific contexts:

• Corticosteroid injections: Case reports exist of hiccups following intra-articular corticosteroid injections 2
• Epidural injections: Persistent hiccups have been reported after cervical epidural steroid injections 4
• Antibiotic injections: Rare cases of antibiotic-induced hiccups have been documented 3

However, there are no specific reports in the reviewed literature about hiccups following routine subcutaneous injections like insulin administration or standard intramuscular injections.

Clinical Implications

For healthcare providers administering SC or IM injections:

• Recognition: Hiccups following injection should be recognized as a potential, albeit rare, adverse effect
• Documentation: Cases should be documented to better establish prevalence
• Management: Most hiccup episodes are self-limiting, but persistent cases may require treatment with:
  • Proton pump inhibitors (first-line therapy, especially if GERD is suspected) 5
  • Other medications like chlorpromazine, gabapentin, or baclofen for persistent cases 1

Prevention and Considerations

When administering SC or IM injections:

• Follow proper injection techniques as outlined in guidelines 6
• For patients with a history of injection-related hiccups, consider:
  • Alternative administration routes if possible
  • Pre-medication if repeated injections are necessary
  • Not repeating injections with the same medication that previously caused hiccups 2

While hiccups following SC or IM injections appear to be rare, healthcare providers should be aware of this potential adverse effect, especially when administering medications known to occasionally trigger hiccups, such as corticosteroids.