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4CPS-187 Pharmacist–clinician collaborative study for prospective identification of drug interactions in HIV patients
  1. I Beristain Aramendi,
  2. A Ros,
  3. J Boo,
  4. T González,
  5. J Landa,
  6. A Eceiza,
  7. C Bachiller,
  8. MJ Gayán,
  9. G Lizeaga
  1. Hospital Universitario Donostia, Hospital Pharmacy Service, Donostia-San Sebastián, Guipuzcoa, Basque Country, Spain


Background and importance As for the general population, HIV patients with antiretroviral treatment (ART) tend to be polymedicated. In this scenario it is crucial to verify the real-time prevalence of interactions and their clinical relevance.

Aim and objectives Review of ART and comedication in HIV patients by a hospital pharmacist in order to detect interactions and improve safety.

Material and methods Prospective study carried out in consecutive patients seen by a physician and a pharmacist between April and May 2021. Variables collected: age, sex, viral load (VL), ART and comedication (according to their Anatomical Therapeutic Chemical (ATC) classification).

Interactions between ART and comedications were reviewed in Lexicomp, Liverpool and Micromedex databases, and classified according to their level of interaction: no interaction and potential weak interaction (little relevance in clinical practice), potential interaction (monitoring is recommended) and contraindicated. Recommendations were developed based on the previously mentioned databases.

Results The study included 100 patients, mean age 48 years, 72% men. VL <50 copies/mL: 95%. Of those 100 patients, 68 used comedication that included 229 drugs, with a mean of 3.3 drugs per patient. Some type of interaction was found in 57 (24.9%) of the 229 drugs (39 (68.4%) potential interaction, 17 (29.8%) potential weak interaction and 1 (1.8%) contraindicated). The main ATC groups with high prevalence of interactions were: nervous system (54%), musculoskeletal system (15%) and cardiovascular system (12%). The remaining minority groups (19%) included alimentary tract, blood and haematopoietic organs, dermatological, anti-infectives and antineoplastic/immunosuppressants. The aforementioned 57 detected interactions affected: comedication (46), ART (9), both (1) and physiological factors (1). As a result, the following recommendations were developed: analytical control of thyroid function, separation of drug intake, drug substitution (antipsychotics, anxiolytics, analgesics), monitoring of immunosuppressant levels, control of kidney function and performance of an electrocardiogram.

Conclusion and relevance Most of the interactions were potential (68.4%), affecting mainly comedication and especially drugs for the nervous system. Even though HIV physicians are well aware of ART interactions, as polymedication increases, real-time pharmacist review is a safety need. It was gratifying to have the opportunity to intercept all these interactions in real-time with the prescriber.

Conflict of interest No conflict of interest

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