When TG levels increased by 200 to 249 mg/dL after gemfibrozil or niacin discontinuation, patients were evaluated for possible underlying causes, which occurred for 4 gemfibrozil and 1 niacin patient. One patient started a β-blocker after gemfibrozil was initiated, and 3 patients were taking gemfibrozil prior to establishing care at the VA. The TG levels of the patient taking niacin correlated with an increased hemoglobin A1c. The TG level for only 1 patient taking gemfibrozil increased above the 500 mg/dL threshold. The patient had several comorbidities known to increase TG levels, but the comorbidities were previously well controlled. No additional medication changes were made at that time, and the TG levels on the next fasting lipid panel decreased to goal. The patient did not experience any negative clinical sequelae from the elevated TG levels.
Thirty-five patients (36%) who were referred to the PACT Pharmacy Clinic required only either gemfibrozil or niacin discontinuation. These patients were evaluated to identify whether adjustments to the protocols would have allowed for pharmacist discontinuation without referral to the PACT Pharmacy Clinic. Twenty-four of these patients (69%) had repeated TG levels ≥ 400 mg/dL prior to referral to the PACT Pharmacy Clinic. Additionally, there was no correlation between the gemfibrozil or niacin doses and the change in TG levels following discontinuation. These data indicate the protocols appropriately identified patients who did not have an indication for gemfibrozil or niacin.
In addition to drug interactions identified on the STOP report, the PACT CPS resolved 12 additional interactions involving simvastatin and gemfibrozil. Additionally, unnecessary lipid medications were deprescribed. The PACT CPS identified 13 patients who experienced myalgias, an ADR attributed to the gemfibrozil- statin interaction. Of those, 9 patients’ ADRs resolved after discontinuing gemfibrozil alone. For the remaining 4 patients, additional interventions to convert the patient to another statin were required to resolve the ADR.
Using pharmacists to address the drug interactions shifted workload from the prescribers and other primary care team members. The mean time spent to resolve both gemfibrozil and niacin interactions by protocol was 15.5 minutes. One hundred fortytwo patients (35.8%) had drug interactions resolved by protocol, saving the PACT CPS’ expertise for patients requiring individualized interventions. Drug interactions were resolved within 4 PACT CPS encounters for 93.8% of the patients taking gemfibrozil and within 3 PACT CPS encounters for 93.8% of the patients taking niacin.
The protocols allowed 12 additional pharmacists who did not have an ambulatory care scope of practice to assist the PACT CPS in mitigating the STOP drug interactions. These pharmacists otherwise would have been limited to making consultative recommendations. Simultaneously, the design allowed for the PACT pharmacists’ expertise to be allocated for patients most likely to require interventions beyond the protocols. This type of intraprofessional referral process is not well described in the medical literature. To the authors’ knowledge, the only studies described referrals from hospital pharmacists to community pharmacists during transitions of care on hospital discharge. 20,21
Limitations
The results of this study are derived from a retrospective chart review at a single VA facility. The autonomous nature of PACT CPS interventions may be difficult to replicate in other settings that do not permit pharmacists the same prescriptive authority. This analysis was designed to demonstrate the impact of the pharmacist in resolving major drug interactions. Patients referred to the PACT Pharmacy Clinic who also had their lipid medications adjusted by a nonpharmacist provider were excluded. However, this may have minimized the impact of the PACT CPS on the patient care provided. As postintervention laboratory results were not available for all patients, some patients’ TG levels could have increased above the 500 mg/dL threshold but were not identified. The time investment was extensive and likely underestimates the true cost of implementing the interventions.