How to Get a Paxlovid Prescription in Canada

Paxlovid is an oral antiviral medication that is intended for individuals who have tested positive for COVID-19, and are considered to be at high risk for the development of severe symptoms.

Paxlovid consists of two different different medications that work in synchronicity to aid the immune system in stopping the COVID virus from replicating.

Nirmatrelvir is the main active ingredient in Paxlovid. It is a protease inhibitor that is responsible for stopping the replication and spread of the COVID-19 infection within the body.

Protease inhibitors interfere with a certain type of enzyme in a way that prevents them from carrying out their normal function.

In the case of a Paxlovid treatment, nirmatrelvir interferes with a key enzyme that is involved in the replication of the COVID-19 virus, effectively stopping the spread of the infection.

Ritonavir does not act directly on the COVID-19 virus itself but instead helps to bolster the effect of nirmatrelvir in the body.

Ritonavir is responsible for the temporary shut down of the body’s ability to metabolize nirmatrelvir.

This helps to increase the concentration of nirmatrelvir in the body for a prolonged period of time, interrupt virus replication, and ultimately put a stop to the continued spread of infection. 

The Paxlovid antiviral drug can be described from a more technical standpoint as ritonavir boosted nirmatrelvir.

The FDA has authorized the use of Paxlovid for individuals aged 12 and older who meet the weight requirements (88 pounds – 40 kilograms). It was approved for distribution in Canada on the 22nd of January 2022.

Paxlovid was granted emergency use authorization in December of last year, around the same time that infection rates skyrocketed as a result of the newly discovered Omicron variant.

In order to qualify for a prescription, patients must have had a positive COVID-19 test and still be within the first 5 days of initial symptom onset for Paxlovid to be effective.

Paxlovid is intended for people who are at higher risk for developing severe illness as a result of COVID-19.

Risk of serious illness is based on health, age and vaccination status.

Higher risk patients include:

• Immunocompromised (immune system that is weakened by underlying conditions and/or medications)

• 18 years of age or older with less than three vaccine doses and at least one risk condition (heart disease, hypertension, kidney disease, lung disease, diabetes etc..)

High risk also refers to individuals who are 65 years of age or older, as more than 80 percent of COVID-19 deaths occur in this age group.

Patients who are pregnant or breastfeeding should speak with their health care provider before moving forward with a Paxlovid treatment.

Patients with a history of renal impairment (kidney problems) may need to have their dosage adjusted, depending on the severity of the impairment.

Your health care provider will be able to evaluate your medical history and current health status in order to determine if you are considered at high-risk of developing serious illness from COVID-19 infection.

Treatment with Paxlovid has been proven to significantly reduce the number of hospitalizations in patients who have tested positive for COVID-19.

Analysis of data from a Pfizer study that included a cohort consisting of over 1200 adults was outlined in a press release.

It was found that individuals who were treated with Paxlovid within three days of symptom onset were 89 percent less likely than patients who were untreated to experience symptom progression to the point of hospitalization.

Paxlovid is classified as an investigational medicine, which means that there are still some aspects of risk that are yet to be studied and reported.

Paxlovid is known to be well-tolerated amongst most individuals who have received treatment.

However, possible side-effects may include:

• Increased blood pressure
• Muscle aches
• Nausea
• Abdominal pain
• Altered or impaired sense of taste (dysgeusia)
• Diarrhea or indigestion
• Malaise (feeling generally unwell)

Paxlovid can be used in eligible patients with mild to moderate kidney problems, defined as having a glomerular filtration rate (eGFR) below 60 milliliters per minute. In these cases, a dosage reduction may be necessary in order to ensure safety.

Patients with severe renal impairment, defined by an eGFR below 30 milliliters per minute, should not take Paxlovid. The appropriate dosage reduction for these individuals has not yet been determined.

• You are allergic to nirmatrelvir, ritonavir or to any of the other ingredients in PAXLOVID (see What are the ingredients in PAXLOVID? below).
• You are taking any of the following medicines:
  1. alfuzosin, used to treat high blood pressure
  2. amiodarone, bepridil, dronedarone, flecainide, propafenone, quinidine, used to treat irregular heart beats
  3. apalutamide, used for prostate cancer
  4. astemizole* or terfenadine*, used to relieve allergy symptoms
  5. cisapride*, used to relieve certain stomach problems
  6. colchicine, when used in patients with kidney and/or liver problems, used to treat gout
  7. ergotamine*, dihydroergotamine (used to treat headaches), ergonovine, methylergonovine* (used afterlabour and delivery)
  8. fusidic acid, used as an antibiotic
  9. lovastatin, lomitapide or simvastatin, used to lower cholesterol
  10. lurasidone, pimozide, used to treat mental health problems
  11. neratinib, used to treat breast cancer
  12. ranolazine, used to treat chronic angina (chest pain)
  13. rifampin and saquinavir, used to treat tuberculosis, should not be used together with ritonavir
  14. rivaroxaban, used as an anticoagulant
  15. salmeterol, used for asthma and chronic obstructive pulmonary disease
  16. St. John’s Wort (Hypericum perforatum), an herbal product used to treat depression
  17. Triazolam and midazolam*(oral or injected), used to relieve anxiety and/or trouble sleeping
  18. PDE5 inhibitors vardenafil, used to treat erectile dysfunction, or sildenafil, used for the treatment of pulmonary arterial hypertension
  19. voriconazole, used as an antifungal
  20. venetoclax during the dose initiation and during the ramp-up phase, used to treat leukemia
  21. carbamazepine, phenobarbital, phenytoin used to treat seizures (epilepsy)
• To help avoid side effects and ensure proper use, talk to your healthcare professional before you take PAXLOVID. Talk about any health conditions or problems you may have, including if you:
  1. Have kidney problems
  2. Have liver problems including hepatitis
  3. Have human immunodeficiency virus (HIV) infection
  4. Are pregnant or breastfeeding