Contrave vs Rybelsus: how two oral prescription options compare in Canada

If you are exploring oral prescription options in Canada and have come across both Contrave and Rybelsus, you are looking at two very different medications. They work through different mechanisms, have different side effect profiles, and suit different patient profiles.

This article explains what each one is and how they differ — so you can have a more informed conversation with a licensed healthcare provider.

A note before we start: Both Contrave and Rybelsus are prescription treatments available in Canada following assessment by a licensed healthcare provider. Neither is appropriate for everyone. This article is general health information, not medical advice.

What is Contrave?

Contrave is an oral tablet that combines two existing medications — naltrexone and bupropion — in a single fixed-dose pill taken twice daily.

Bupropion is an aminoketone that acts on dopamine and norepinephrine pathways in the central nervous system. Naltrexone is an opioid antagonist. The two act on different pathways simultaneously.

What is Rybelsus?

Rybelsus is an oral tablet containing semaglutide — the same active ingredient found in injectable GLP-1 treatments such as Ozempic and Wegovy. It is the first oral GLP-1 receptor agonist approved in Canada.

Rybelsus works by binding to GLP-1 receptors. It uses an absorption-enhancing technology to allow semaglutide to pass through the gut lining and enter the bloodstream — a formulation challenge that made oral delivery of this molecule possible.

The maximum approved dose of Rybelsus in Canada is 14 mg daily. Higher-dose oral semaglutide formulations (25 mg and 50 mg) have been studied in clinical trials but are not yet approved in Canada as of mid-2026.

Key differences at a glance

How they differ in practice

Dosing and administration

Contrave is taken twice daily and follows a gradual titration schedule — starting at one tablet in the morning, building to the full dose of two tablets twice daily over four weeks. It can be taken with or without food, though a high-fat meal may increase bupropion exposure.

Rybelsus must be taken first thing in the morning, on an empty stomach, with a small amount of water (no more than 120 mL), at least 30 minutes before eating, drinking anything else, or taking other medications. This strict administration window is necessary for adequate absorption. Missing this window or taking it with food significantly reduces how much of the drug reaches the bloodstream.

For patients with busy mornings, Rybelsus's rigid dosing window can be a practical challenge. Contrave's twice-daily schedule is more flexible on timing but requires remembering a second dose each day.

Contraindications and cautions

Contrave is not appropriate for patients with a history of seizures, eating disorders (such as bulimia or anorexia), patients currently taking opioid medications or in acute opioid withdrawal, or patients on MAO inhibitors. The bupropion component carries a Health Canada boxed warning regarding suicidal thoughts and behaviours.

Rybelsus is not appropriate for patients with a personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia syndrome type 2.

A licensed healthcare provider will assess your full health history before prescribing either medication.

Side effect profiles

Contrave's most commonly reported side effects include nausea, constipation, headache, vomiting, dizziness, and insomnia. Because bupropion affects the seizure threshold, Contrave carries a seizure risk and is contraindicated in patients with seizure disorders.

Rybelsus shares the GI side effect profile common to all GLP-1 medications: nausea, diarrhea, constipation, and vomiting — predominantly in the early weeks and after dose increases.

The bottom line

Contrave and Rybelsus are two meaningfully different oral prescription options. Contrave acts on CNS pathways through a combination of two established medications. Rybelsus is an oral formulation of semaglutide — the same active ingredient as injectable GLP-1 treatments.

A licensed healthcare provider can assess your health history, current medications, and circumstances to determine which option, if any, is appropriate for you.

FAQs

Is Contrave available in Canada?

‍Yes. Contrave (naltrexone/bupropion) is available in Canada by prescription following assessment by a licensed healthcare provider.

Is Rybelsus available in Canada?

‍Yes. Rybelsus (semaglutide) is available in Canada by prescription following assessment by a licensed healthcare provider.

Which has fewer side effects — Contrave or Rybelsus?

‍Both have distinct side effect profiles. Contrave's most commonly reported effects include nausea, headache, and insomnia. Rybelsus shares the GI profile of GLP-1 medications including nausea, diarrhea, and constipation. A licensed healthcare provider can help assess which is more appropriate given your individual health history.

Can I take Contrave if I am on pain medication?

‍No. Contrave contains naltrexone, an opioid antagonist. Taking it alongside opioid-containing medications is contraindicated. Speak with your prescriber before starting Contrave if you take any opioid-containing medications.

Are there injectable alternatives to these oral options?

‍Yes. Injectable GLP-1 treatments including Ozempic and Wegovy are available in Canada by prescription following assessment by a licensed healthcare provider. A clinician can help determine whether an injectable or oral option is more appropriate for your situation.

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