Interaction between COVID-19 Vaccine and Paracetamol, Chlorpheniramine and Prednisolone

Interaction between COVID-19 Vaccine and:	Paracetamol	Chlorpheniramine	Prednisolone
Lexicomp Interaction Category	D: Consider therapy modification	D: Consider therapy modification	C: Monitor therapy
Summary	Paracetamol may diminish the therapeutic effect of vaccines. This interaction only applies to prophylactic use of acetaminophen before or during vaccine administration.	Antihistamines may enhance the adverse / toxic effect of COVID-19 Vaccine.  Specifically, the prophylactic use of antihistamines may mask symptoms and delay diagnosis and management of anaphylaxis.	Immunosuppressants may diminish the therapeutic effect of COVID-19 Vaccine
Patient Management	Consider avoiding routine prophylactic use of paracetamol before or during vaccine administration when possible. Paracetamol is still recommended to treat fevers and/or pain that occur after vaccination.	Do not administer antihistamines to COVID-19 vaccine recipients prior to vaccination to prevent allergic reactions. Antihistamines do not prevent anaphylaxis, and their use may mask cutaneous symptoms, which could lead to a delay in the diagnosis and management of anaphylaxis.	·   The COVID-19 vaccine (mRNA) has not been systematically studied in individuals receiving immunosuppressant therapy. While this combination is expected to be safe, reduced efficacy of the vaccine (eg, reduced immune response) may occur if administered to patients on immunosuppressant therapy. ·   If possible, based on recommendations for the timing of inactivated vaccines, administer the COVID-19 (mRNA) vaccine series at least 2 weeks prior to initiation of immunosuppressant therapy. ·   Decisions to delay immunosuppressive therapy to complete COVID-19 vaccination should consider the person’s risks related to their underlying condition. ·   Patients vaccinated less than 14 days before starting immunosuppressant therapy or while receiving immunosuppressant therapy may get less than full protection from the vaccine; hence advised to continue to carefully adhere to current public health recommendations regarding social distancing, wearing a mask, avoiding large gatherings, and other guidance regarding minimizing possible exposure to the virus.
Proposed Mechanisms	Paracetamol suppression of the inflammatory response, which is an important component of the host response to vaccine administration.		Likely decreased immune response to inactivated vaccines due to immunosuppression.
Remark(s)		Only found for mRNA and adenovirus vector.

 *COVID-19 vaccines placed in the search include mRNA, inactivated virus and adenovirus vector.

However, pre-med may be suggested by physician / allergist / immunologist in specific individual cases.

Reference:   Lexicomp Drug Interaction: Online [Accessed on 28 March 2021]     by J. Ho