Cialis vs Viagra: What’s the Difference?

Cialis and Viagra are the same class of medication, and for most men, they work about as well as each other. What separates them is time. Viagra is effective for a window of roughly four to six hours, while Cialis can still be working a day and a half after you take it.

That timing difference is what influences choice most. If you’d rather take a tablet on Friday evening and not think about it again until Sunday, Cialis might be the best choice. If you have sex occasionally and would rather the drug be out of your system by morning, Viagra could be the better fit.

Despite that simple explanation, we know most men will still have some questions about Cialis vs Viagra in Canada. So in this article, we cover what each drug is, how the medications differ, and who each one might suit best. We also look at side effects, what Viagra and Cialis cost in Canada, and how to get a prescription from an online doctor.

What Is Cialis?

Cialis is a prescription medication that treats symptoms of erectile dysfunction in adult males. Cialis belongs to a class of drugs known as phosphodiesterase type 5 inhibitors (PDE5 inhibitors for short), which work by increasing blood flow to the penis during sexual stimulation. The active ingredient in Cialis is tadalafil, which comes as a tablet.

Health Canada lists four strengths of Cialis: 2.5 mg, 5 mg, 10 mg and 20 mg. The 10 mg and 20 mg tablets are recommended for on-demand dosing, taken before sex, while the 2.5 mg and 5 mg tablets are typically for once-a-day use.

Eli Lilly has sold Cialis in Canada since 2003, but most Canadians filling a prescription today are handed a generic instead. Generic tadalafil reached the Canadian market in July 2016, and around twenty manufacturers now hold approvals here. Branded and generic tablets contain the same active ingredient at the same strength. For more details on Cialis dosing, cost and side effects, see our tadalafil article.

What Is Viagra?

Viagra is a well-known prescription drug that revolutionized the treatment of erectile dysfunction. Health Canada authorised Viagra in March 1999, almost five years before Cialis reached the Canadian market. The active ingredient in Viagra is sildenafil, which works by inhibiting phosphodiesterase-5.

Viagra comes in three strengths in Canada: 25 mg, 50 mg and 100 mg. Most men start on 50 mg, taken 30 to 60 minutes before sex, and a doctor can move the dose up or down from there. Sildenafil is taken on demand, and there’s no once-a-day version of Viagra approved for erectile dysfunction in Canada.

Pfizer had the Canadian market to itself until November 2012, when the Supreme Court of Canada voided its patent and generic sildenafil went on sale the same day. Brand Viagra is still sold here, but as with Cialis, most prescriptions are now filled with a generic.

What Is the Difference between Viagra and Cialis?

Viagra (sildenafil) and Cialis (tadalafil) are both prescription medications used to treat erectile dysfunction (ED). Both drugs belong to a class of medications known as phosphodiesterase type 5 inhibitors, which work by increasing blood flow to the penis during sexual arousal.

Shared Mechanisms and Differences

Sildenafil and tadalafil block the same enzyme in the same tissue, and response rates across the class are broadly similar. What differs is how long each drug stays in your body. Sildenafil has a half-life of about four hours; tadalafil’s is closer to 17.5 hours. Almost every practical difference between Viagra and Cialis follows from that one number.

Key variations between the medications include:

• How long each lasts — Viagra’s effects last about four to six hours. Cialis can still be working up to 36 hours after a dose. Neither is a hard cut-off; both describe a window where each drug is likely to help, tailing off rather than switching off.
• How quickly each starts — both take effect in roughly 30 to 60 minutes. Cialis peaks in the blood later, at about two hours, but it doesn’t take longer to begin working.
• The daily option — Cialis is available in a daily formulation for men who engage in sexual activity frequently. Viagra has no equivalent in Canada.
• Food — a heavy, fatty meal delays the onset of Viagra by about an hour, and lowers its peak level by roughly 29%. Cialis is absorbed the same way with or without food.
• Cost — both are sold as Canadian generics at a fraction of the brand price. Tablet for tablet, generic sildenafil (Viagra) is usually the cheaper of the two.

Both Viagra and Cialis do not cause an erection on their own, and require sexual arousal to work. Neither should be taken without consulting a doctor, as both can have side effects and interact with other medications.

Which Is Better: Cialis vs Viagra?

Neither one is better. Both are treatments for erectile dysfunction, and how well each works will depend on the person’s response and needs. What makes the choice manageable is that Cialis and Viagra suit different habits rather than different men.

Cialis might be the best fit if:

• You’d rather not plan — one tablet on a Friday evening covers most of the weekend.
• You have sex more than about twice a week — the daily 2.5 mg or 5 mg tablet is simpler, and often cheaper, than buying on-demand tablets.
• You often eat before sex — food doesn’t change how Cialis is absorbed.

Viagra could be ideal if:

• You have sex occasionally — generic sildenafil is usually the cheaper tablet, and you only buy what you use.
• You’d rather the drug cleared quickly — sildenafil is largely gone within about a day, while tadalafil takes closer to two.
• Cialis has given you back or muscle aches — a small number of men get these 12 to 24 hours after a dose, and sildenafil doesn’t tend to cause them.

On safety, there’s little difference between Viagra vs Cialis. The serious side effects and risks belong to the drug class itself rather than to either brand, and a doctor screens for the same things before prescribing either one.

Comparing Cialis vs Viagra Side Effects

It’s worth noting that most men get no side effects at all from Cialis or Viagra, or mild ones that settle by themselves.

In the Canadian Cialis trials, the most common side effects were:

• Headache (11%)
• Indigestion (7%)
• Back pain (4%)
• Muscle aches (4%)
• Nasal congestion (4%)
• Flushing (4%)

Viagra’s list is much the same: headache, flushing, indigestion, nasal congestion and dizziness. Not everyone who uses Viagra or Cialis will experience side effects, and they can be dose-dependent. Headache and flushing are short-lived with either drug.

Important Considerations

Two differences related to side effects and risk are worth knowing about before you choose:

1. Some men experience back and muscle aches while taking tadalafil (Cialis), which tend to arrive 12 to 24 hours after a dose and settle within a couple of days.
2. Sildenafil (Viagra) can cause a blue tinge to vision, sensitivity to light, or mild blurring. The effect seems to be dose-related, more commonly occurring on a 100 mg tablet than a 25 mg one. Canadian trials reported it in 2.7% of men, and the changes are described as mild and temporary rather than lasting. The advice is simply not to drive until your vision is back to normal.

Serious Reactions

Severe side effects from Viagra and Cialis are rare. The ones to look out for are:

• An erection lasting more than four hours
• Sudden loss of vision
• Sudden hearing loss

If any of the above occur, stop taking the drug and get medical attention immediately.

Neither Cialis nor Viagra can be taken with nitrate medication (including recreational “poppers”). If taken together, they can drop blood pressure to a dangerous level. The safe gap between taking nitrate medication and Cialis or Viagra differs between the drugs. 

The Canadian information for Cialis specifies at least 48 hours after the last dose, while sildenafil clears considerably faster. Either way, this is a question for the doctor treating you rather than one to work out yourself.

Cialis vs Viagra Price in Canada

Most Canadians pay for erectile dysfunction medication out of pocket, so the cost of Viagra and Cialis is an important consideration. 

Using Ontario’s public formulary as a guide to Canadian generic pricing:

• A pack of four on-demand tablets — costs roughly $30 to $40 for generic sildenafil, and around $45 to $55 for generic tadalafil at 20 mg.
• A month of daily tadalafil — priced around $100 to $115 a month for a 2.5 mg or 5 mg tablet every day.
• Brand Cialis and brand Viagra — no listed public price at all, and both cost substantially more than the generics.

The figures above are formulary prices rather than what you’ll pay at the counter. Retail prices vary between pharmacies and dispensing fees are extra, so confirm current pricing with your pharmacy.

Erectile dysfunction medication is one of the more common exclusions from public drug plans across Canada. In BC, for example, PharmaCare covers tadalafil and sildenafil only for pulmonary arterial hypertension, not for erectile dysfunction. Private and workplace plans vary: some cover ED medication, many exclude it, and some cap how many tablets you can claim in a year.

Viagra vs Cialis vs Levitra: Where the Third ED Pill Fits

Canada has a third erectile dysfunction tablet called Levitra. Levitra is the brand name for vardenafil, and it behaves much like Viagra — effective for around four to five hours, slowed by a heavy meal, taken soon before sex. Bayer discontinued branded Levitra in Canada in December 2022, but generic vardenafil is still sold here in 5 mg, 10 mg, and 20 mg tablets.

Do You Need a Prescription for Cialis in Canada?

Cialis is a prescription medication in Canada, and it can only be obtained with a valid prescription from a healthcare professional. The main reason is that Cialis lowers blood pressure slightly, so a doctor needs to check your health history and other medications first. 

Erectile dysfunction can also be an early sign of heart or circulation problems, which is one of the things a doctor looks at during the appointment.

Do You Need a Prescription for Viagra?

Viagra has been prescription-only in Canada since Health Canada authorised it in 1999, and generic sildenafil is prescription-only as well. No Canadian pharmacy can dispense Viagra without a prescription.

Is Cialis Over the Counter in Canada?

Nothing sold over the counter in Canada contains licensed tadalafil or sildenafil. What you may find on shelves and online are “natural” male enhancement supplements. Health Canada has recalled these repeatedly after testing found undeclared prescription drugs inside them. Counterfeit Cialis and Viagra tablets have also been seized from Canadian retailers.

Getting a Prescription for Cialis or Viagra Online

Erectile dysfunction is diagnosed mainly from your history rather than from a physical examination, which is what makes it well suited to an online doctor’s appointment.

The appointment covers what you’ve been experiencing and for how long, your general health history, and the other medicines you take. If Cialis or Viagra is a suitable option, the doctor can issue a prescription.

In British Columbia, an appointment with a Walk In doctor is covered by MSP, so the consultation itself costs nothing out of pocket, and you can usually book the same day.

Frequently Asked Questions About Cialis and Viagra

Can you take Cialis and Viagra together?

No, and it wouldn’t double the effect anyway. Both drugs act on the same enzyme and both lower blood pressure a little, so taking them together mainly increases the chance of side effects and a blood pressure drop. If one isn’t working well, the answer is a conversation with your doctor about the dose or a switch, not taking both at once.

What if the first tablet doesn’t seem to work?

That happens often enough that Canadian urology guidance addresses it directly. Before deciding that Viagra or Cialis has failed, it’s worth checking how it was taken, whether there was enough time between the tablet and sex, whether there was arousal, and whether a heavy meal got in the way (if it was Viagra). The guidance suggests several attempts and often a dose or timing adjustment before concluding a medication doesn’t suit you.

Are generic tadalafil and sildenafil as good as Cialis and Viagra?

Health Canada requires a generic to contain the same medicinal ingredient at the same strength as the brand version. The only practical difference between brand and generic Viagra or Cialis is price.

Which is safer, Cialis or Viagra?

Neither Viagra nor Cialis is safer than the other. The serious risks belong to the drug class rather than to either medication, and the same checks apply before either is prescribed. The one practical difference is timing: because tadalafil stays in your body far longer, anything it does, welcome or not, lasts longer.

Choosing Between Cialis and Viagra

Cialis and Viagra both treat erectile dysfunction in a similar way, and for most men, either one will work. The choice between which one is best comes down to how often you have sex, whether you’d rather plan ahead or not think about timing for taking the medication, and what you’re willing to spend per tablet.

If you’d rather not plan and expect to use the medication more than about twice a week, Cialis is usually the better fit. If you have sex occasionally and want to pay per tablet, Viagra tends to make more sense.

If erectile dysfunction is affecting you and you’re not sure which option fits, an online doctor from Walk In can help.

Speak to a Doctor Online About Erectile Dysfunction Treatment