Exhibit 12.1
– Certification of CEO pursuant to Section 302



CERTIFICATION



I, Albert D. Friesen, certify that:



1. I have reviewed this Annual Report on Form
20-F of Medicure Inc.;



2. Based on my knowledge, this report does
not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in
light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;



3. Based on my knowledge, the financial statements,
and other financial information included in this report, fairly present in all material respects the financial condition, results
of operations and cash flows of the company as of, and for, the periods presented in this report;



4. The company's other certifying officer(s)
and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e)
and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15(d)-(15)(f)) for
the company and have:



| | (r) | Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the company, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;                                                                                                                                                                
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| | (s) | Designed such internal control over financial reporting, or caused
                                         such internal control over financial reporting to be designed under our supervision,
                                         to provide reasonable assurance regarding the reliability of financial reporting and
                                         the preparation of financial statements for external purposes in accordance with generally
                                         accepted accounting principles;



| | (t) | Evaluated the effectiveness of the company's disclosure controls
                                         and procedures and presented in this report our conclusions about the effectiveness of
                                         the disclosure controls and procedures, as of the end of the period covered by this report
                                         based on such evaluation; and
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| | (u) | Disclosed in this report any change in the company's internal
                                         control over financial reporting that occurred during the period covered by the annual
                                         report that has materially affected, or is reasonably likely to materially affect, the
                                         company's internal control over financial reporting; and
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5. The company's other certifying officer(s)
and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the company's auditors
and the audit committee of the company's board of directors (or persons performing the equivalent functions):



| | (j) | All significant deficiencies and material weaknesses in the
                                         design or operation of internal control over financial reporting which are reasonably
                                         likely to adversely affect the company's ability to record, process, summarize and report
                                         financial information; and
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| | (k) | Any fraud, whether or not material, that involves management
                                         or other employees who have a significant role in the company's internal control over
                                         financial reporting.
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|Date April 26, 2017 | /s/ Albert Friesen           
|------------------- | -----------------------------
|                    | Chief Executive Officer      
|                    | (Principal Executive Officer)