Occurrence of hemodynamic changes following administration of rocuronium in a dog presenting for an ophthalmic procedure.

A 10-year-old, neutered male, Golden Retriever dog presented for surgical correction of a descemetocele. Acepromazine (0.02 mg/kg) and methadone (0.5 mg/kg) were administered intramuscularly for sedation, propofol (2 mg/kg) and midazolam (0.2 mg/kg) were administered intravenously for anaesthetic induction and isoflurane in oxygen was utilised for anaesthetic maintenance. Rocuronium (0.5 mg/kg), a neuromuscular blocking agent, was administered intravenously to facilitate central positioning of the eye for surgery. Within 10 min of rocuronium administration, the dog became tachycardic and hypotensive. Hemodynamic aberrations did not resolve with initial interventions but were successfully mitigated with the administration of diphenhydramine (0.8 mg/kg) intravenously. The dog remained stable throughout the remainder of the procedure and experienced a smooth and uneventful recovery. While it is difficult to confirm that the hemodynamic changes observed in this clinical case resulted solely from administration of rocuronium, the observance of the cardiovascular changes, timing of events and response to therapy suggest that rocuronium elicited a histamine response that was successfully treated with diphenhydramine.

Diphenhydramine and Migraine Treatment Failure in Pediatric Patients Receiving Prochlorperazine.

OBJECTIVES: The objectives are to determine whether diphenhydramine coadministered with prochlorperazine versus prochlorperazine only is associated with a difference in the risk of migraine treatment failure, as measured by the need for additional therapy, hospitalization rates, and 72-hour return rates, and to compare extrapyramidal adverse effects between groups. METHODS: Retrospective cohort of patients aged 7 to 18 years treated in the emergency department for migraines using prochlorperazine with or without diphenhydramine between 2013 and 2019. Patients were included if they had International Classification of Diseases, Ninth or Tenth Revision, codes for migraine or unspecified headache and were treated with prochlorperazine as part of their initial migraine therapy. Data collected included demographics, medications administered, pain scores, neuroimaging, disposition, return visits, and documentation of extrapyramidal adverse effects. Multivariable logistic regression was used to estimate the association between diphenhydramine coadministration and each of the outcomes. RESULTS: A total of 1683 patients were included. Overall, 13% required additional therapy with a 16.7% admission rate and a 72-hour return rate of 5.3%. There was no association between initial treatment with diphenhydramine and the odds of additional therapy (adjusted odds ratio [aOR], 0.74 [95% confidence interval {CI}, 0.53-1.03]), admission rates (aOR, 1.22 [95% CI, 0.89-1.67]), or return visit rates (aOR, 0.91 [95% CI, 0.55-1.51]). Extrapyramidal adverse effects occurred in 2.4% of patients in the prochlorperazine group and 0% in the prochlorperazine with diphenhydramine group. CONCLUSIONS: There was no association between diphenhydramine coadministration and the need for additional therapy, 72-hour return visit rates or admission rates. Extrapyramidal effects did not occur in patients treated with diphenhydramine.

Comparing the Risk of Infusion-Related Reactions and Tolerability in Patients Given Cetirizine or Diphenhydramine Prior to Ocrelizumab Infusion (PRECEPT).

Background: Ocrelizumab is an effective medication for multiple sclerosis. However, infusion-related reactions (IRRs) are a concern for patients and may lead to discontinuation of ocrelizumab. To minimize IRRs, pre-medications are administered. However, from our experience, these medications, especially diphenhydramine, can cause marked drowsiness. The primary objective of this study was to evaluate whether cetirizine is non-inferior to diphenhydramine in limiting the proportion and severity of reactions from ocrelizumab infusions. Methods: Twenty participants were serially randomized in a 1:1 ratio to receive 10 mg of cetirizine or 25 mg of diphenhydramine orally prior to their first three ocrelizumab infusions. Results: The rate of IRRs in this study was similar across both treatment groups with no increase in the risk of severity, and no grade 3 IRRs. Further, patients receiving cetirizine experienced a reduction in fatigue. While there was not a significant difference in global satisfaction, this score increased over time in the cetirizine arm while it remained unchanged in the diphenhydramine arm. Conclusions: Overall, our results suggest that cetirizine does not increase the risk of infusion-related reactions compared to diphenhydramine.

Beneficial effects of diphenhydramine in dystonia

The objective of this paper was to evaluate the efficacy of diphenhydramine hidrochloride (DPH) in dystonic patients. In 1995, Truong et al reported encouraging results in five patients with idiopathic torsion dystonia (ITD) treated with DPH, an H1 antagonist with sedative and anticholinergic properties. Five patients with generalized ITD, one with secondary generalized dystonia and one with idiopathic segmental dystonia were included in the prospective study, initialy the response to intravenous administration of DPH versus placebo in two sessions a week apart was evaluated. Two weeks later all patients started oral DPH in increasing doses (range 100-300 mg, mean 164 mg). The degree of dystonia was determined by a modified University of Columbia Scale evaluating the baseline score, after placebo and DPH I.V. administration then at one and six months after starting oral treatment. The results were analyzed by Friedman's test for repated measurements. On comparing scores for baseline severity, I.V. placebo and I.V. DPH presented a highly significant correlation (12.09; p = 0.00) as well as comparing baseline score with oral DPH at one and 6 months, treatment (12.78; p = 0.00). Functional score results were 9.5 p = 0.01 and 8.4 p = 8.4 p = 0.02 at one and 6 months respectively. The most common side effects were sommolence and dizziness. It can be concluded that DPH proved effective in our patients with mild to moderate adverse effects not requiring drug withdrawal in any case. However, I.V. challenge was unable to predict the long-term response to oral medication perhaps due to the limited number of cases.