New Evidence

In this trial, Ruberto et al randomized 13 patients to intravenous haloperidol (either 0.05 or 0.1 mg/kg) and 17 patients to 8 mg of intravenous ondansetron.⁵ Haloperidol outperformed ondansetron at two hours after treatment, reducing pain and nausea 2.3 points more than ondansetron on a 0–10 scale (difference 2.3 cm; 95% CI, 0.6–4.0). The authors sliced and diced the data, looking at multiple outcomes (various pain and nausea measurements, administration of rescue medications, and length of stay). Essentially, all of the secondary outcomes favored haloperidol, although these results are not conclusive given the small size and design of the trial. 

While the study was too small to demonstrate the superiority of one dose of haloperidol over the other in a statistical manner, when the researchers looked at trends in pain scores, the high-dose haloperidol group did not seem to trend to faster or better reduction of pain and nausea. Importantly, there were three occurrences of akathisia or dystonia in patients in the haloperidol group—all of whom received the high-dose haloperidol regimen. Although the study is small, these results are conclusive enough to state the following: Forget the idiom that says, “go big or go home.” In fact, the low-dose haloperidol group was something of a misnomer; subjects in the “low-dose” group received what many of us would consider to be a normal, if not hefty, dose of haloperidol. Most subjects in the “low-dose” arm of the study received more than the 2.5 mg IV dose that many practitioners use for nausea and vomiting today. The “high-dose” group meanwhile, might have better been called the “very high-dose” group—a 70-kg patient would have received 7 mg of haloperidol. 

Turning Up the Heat

In addition to haloperidol and droperidol, capsaicin has been touted as a treatment for CHS in numerous case reports.^6-9 Similar to hot showers, this topical treatment activates receptors responsible for the sensation of heat and has been used as an analgesic. In Academic Emergency Medicine, Dean et al report results from a pilot randomized trial of 30 patients with CHS.¹⁰ In this blinded trial, 17 patients were randomized to 0.1% topical capsaicin and 13 to a moisturizing lotion placebo. At 30 minutes, nausea fell by about 2 points on a 10-point scale in both groups. But at 60 minutes, nausea was reduced by another full point in the capsaicin group, while those in the placebo group reported no change. Fewer patients in the capsaicin group received antiemetics both before randomization and as a rescue medication. 

Although these randomized studies are small, they confirm the treatment of CHS that many have adopted on the grounds of anecdotes, retrospective data, and clinical practice. It appears that the butyrophenones (haloperidol and droperidol) are effective antiemetics and capsacin may also have a role.