The administration of an intravenous injection is an entirely different procedure than the administration of an intramuscular (IM) injection. These injections are administered deep into the body of a muscle, such as the deltoid or the gluteus. After the syringe is inserted, the plunger is pulled back to determine if a vein has been punctured before the medication is injected to ensure that the medication is administered intramuscularly and not intravenously. Intravenous administration causes a much faster drug action time than does intramuscular administration. While some medications can be administered both IV or IM, some are restricted to one route or dangerous side effects can occur.
Zhou and co-workers (2015) discussed existing and emerging therapeutic options, and examined studies focusing on palonosetron with regards to efficacy, pharmacology, tolerability, safety, and patient-derived outcomes. These investigators performed a literature search using Ovid MEDLINE and EMBASE to identify relevant studies using palonosetron alone or in combination with other anti-emetics. Studies were extracted if they included complete response (CR), complete control (CC), no nausea, no vomiting, and no rescue medications as an end-point. Studies were also included if safety end-points were examined. Palonosetron alone has been shown to improve CR and CC rates for patients receiving low, moderate, or high emetogenic chemotherapy. Rates were further improved with the addition of dexamethasone. Furthermore, the addition of neurokinin-1 receptor antagonists, such as netupitant markedly improved efficacy profiles compared to palonosetron alone. Aprepitant is an anti-emetic that has exhibited positive results in combination with palonosetron. Recently, a new drug consisting of netupitant and palonosetron (NEPA) has demonstrated significantly more effective prevention of CINV. Regardless of the combination, palonosetron has been well-tolerated. The most common adverse events were constipation, headache, fatigue, and dizziness, with the majority of patients describing them as only mild or moderate. The authors concluded that palonosetron, alone or with other anti-emetics, has improved CINV treatment due to its ability to significantly reduce delayed phases of CINV, compared to similar 5-HT3RAs. They stated that palonosetron is both more effective than first generation 5-HT3RAs and safer, as it results in a smaller prolongation of the QTc interval, compared to other 5-HT3RAs.