Thompson, Virginia H.

Drug interactions are common and can affect patient outcomes. Drugs that undergo emergency approval have less preapproval drug testing to identify potential interactions. Tramadol is an effective pain medication prodrug with a complex mechanism of action that requires extensive metabolism. Remdesivir is an antiviral medication given emergency approval to treat hospitalized patients with COVID-19 infections. Remdesivir is also a nucleotide analogue prodrug that undergoes intracellular metabolic conversions to its active metabolite. We discuss the case of a hospitalized patient in the United States diagnosed with COVID-19 pneumonia who developed acute pain crisis secondary to a drug–drug interaction between tramadol and remdesivir, and we propose a possible mechanism of interaction.

In the absence of suitable oral or intravenous access for medication administration and when the intramuscular medications are undesirable, alternative routes for drug delivery may be considered. Antipsychotics administered via an inhaled, intranasal, rectal, or topical route have been described in the literature. Topically administered antipsychotics have been previously reported to produce negligible systemic absorption despite being used in clinical practice for nausea and behavioral symptoms associated with dementia. Additionally, the American Academy of Hospice and Palliative Medicine recommends against the use of topical medications that lack supporting literature. Three studies have assessed the systemic absorption of different antipsychotics after administration of only a single, topically applied dose. To evaluate whether the repeated administration of a topically applied antipsychotic may result in detectable serum levels in an accumulating fashion, a pharmacokinetic study was conducted. Five healthy, adult participants consented to receive extemporaneously prepared topical quetiapine in Lipoderm every 4 hours for a total of 5 doses. Blood samples were drawn at baseline and hours 2, 4, 8, 12, 16, and 24, and serum quetiapine concentrations were measured using high-performance liquid chromatography. Quetiapine was undetectable in every sample from 3 participants. Two participants had minimally detectable serum quetiapine levels no sooner than hour 12 of the study period. Extemporaneously prepared quetiapine in Lipoderm resulted in nonexistent or minimal serum level following repeated topical administration. The use of topically applied quetiapine should still be questioned.