Two 5 mg tadalafil tablets add up to 10 mg, a dose many men are routinely prescribed, so the number itself is not unusual. Whether it is a reasonable choice depends less on the pills than on what is already in your body: a daily dose that has built up, a heart medicine, or kidneys that clear drugs slowly. Tadalafil also lasts far longer than other erection pills, so a second tablet keeps adding to the first well into the next day.
What Two 5 mg Tablets Add Up To
Tadalafil is prescribed in two ways. Once-daily dosing means a pill every day at 2.5 or 5 mg. As-needed (on-demand) dosing means a pill before sex at 10 or 20 mg.1Oxford Academic (The Journal of Sexual Medicine). Efficacy of Continuous Dosing of Tadalafil Once Daily vs Tadalafil On Demand in Clinical Subgroups of Men with Erectile Dysfunction: A Descriptive Comparison Using the Integrated Tadalafil Databases Two 5 mg tablets therefore give exactly the as-needed starting dose of 10 mg. As-needed tadalafil is taken no more than once a day, and 20 mg is the usual maximum. The amount reaching your blood rises in step with the dose, so 10 mg gives about twice the drug of 5 mg.2U.S. Food and Drug Administration. CIALIS (tadalafil) tablets Side effects such as headache and flushing tend to rise with the dose.
The same 10 mg acts differently depending on who swallows it. A man who takes nothing daily starts from zero, so 10 mg is a normal single dose. A daily user already has tadalafil circulating, which the next section covers.
Tadalafil reaches its highest level in the blood about 2 hours after you swallow it.3PubMed Central. Tadalafil pharmacokinetics in healthy subjects It then takes around 17.5 hours for half of it to leave the body in healthy men, and about 21.6 hours in older men.4PubMed Central. Tadalafil in the treatment of erectile dysfunction That is why a single dose can help erections for up to 36 hours, versus about 4 hours for sildenafil (Viagra).5PubMed Central. Phosphodiesterase type 5 inhibitor differentiation based on selectivity, pharmacokinetic, and efficacy profiles
That 2-hour peak is also why as-needed tadalafil is usually taken some time before sex. Taking a second tablet because the first seems slow is the mistake to avoid, since the first one is still being absorbed. The drug helps blood vessels in the penis relax when you are aroused; it does not cause an erection on its own.
Your label tells you which plan you are on. A bottle labelled for once-daily use and one labelled for use before sex can hold the same 5 mg tablets. If your directions say one tablet each day, taking two is a change to your prescription, not a way of following it. Pharmacy labels are matched to your records, so if the dose you want to take differs from the one printed on yours, call before you act.
Taking two whole tablets is different from splitting one, because each intact tablet is made to hold its full labelled amount.6Lilly Medical. Can Cialis (tadalafil) tablets be crushed or split?
Doubling Up When You Already Take 5 mg Daily
Because each dose lingers, daily tadalafil reaches a steady level within about 5 days.7U.S. Food and Drug Administration. CIALIS (tadalafil) tablets Roughly half of a dose is still present after a day, so tomorrow is never a fresh start. At that point the amount in your blood is about 1.6 times what one dose alone gives.8U.S. Food and Drug Administration. CIALIS (tadalafil) tablets A second 5 mg tablet on top of that pushes levels higher than a man taking 10 mg once would reach. More drug in the blood raises the chance of low blood pressure, fainting, vision changes and long erections.9PDR. Drug Summary
If you take 5 mg daily and want an extra boost for the weekend, ask your doctor about a planned switch to as-needed dosing instead of improvising.
The extra tablet also buys little. Men on daily tadalafil scored slightly better on erection questionnaires than as-needed users, a gap small enough that it may not be noticeable.10PubMed. The Efficacy of Tadalafil Daily vs on Demand in the Treatment of Erectile Dysfunction: A Systematic Review and Meta-analysis
If you forget a daily dose, take it when you remember, but never take two doses on the same day. Because tadalafil lasts so long, one missed day usually has little effect on how well it works.
“Once a day” means roughly every 24 hours, not any time within a calendar day. A tablet at 11 pm and another at 7 am are effectively two doses close together. Keep a fixed time each day, and consider a weekly pill organizer so you can confirm whether you already took today’s.
If you take an extra tablet and feel fine, that does not prove it was safe. One uneventful extra dose is not a reason to repeat it, since your response can differ with other medicines, alcohol or dehydration.
If you took two doses by accident, don’t take extra to make up or adjust; simply go back to one tablet at your usual time. Be careful standing up quickly, and don’t drive if you feel lightheaded. Seek medical advice if you feel faint, have chest pain or vision changes, or if you take nitrate heart medicines or an alpha-blocker.
Who Should Never Take Two Tablets
Nitrates are chest-pain medicines such as nitroglycerin sprays, tablets under the tongue, or patches. They must never be combined with tadalafil.11PubMed. Time course of the interaction between tadalafil and nitrates In men with chest pain from heart disease, tadalafil plus nitroglycerin dropped standing blood pressure by more than 30 points on average, and more men fell below 85, a level that can cause fainting.12PubMed. Cardiovascular effects of tadalafil Both nitrates and tadalafil relax blood vessels, so together the effect is much larger than either alone. This is about timing, not dose: even a single 5 mg tablet can be a problem if you have used nitrates in the same period. If you might need nitroglycerin, tell emergency staff when you last took tadalafil, since it stays active for a day or more.
Some prostate and blood-pressure pills add to the drop. With doxazosin, a blood-pressure and prostate pill, 20 mg tadalafil lowered standing blood pressure about 10 points more than doxazosin alone.13PubMed. Interaction between the phosphodiesterase 5 inhibitor, tadalafil and 2 alpha-blockers, doxazosin and tamsulosin in healthy normotensive men And 28% of men on doxazosin plus tadalafil dropped below 85, versus 6% on doxazosin alone.14PubMed. Interaction between the phosphodiesterase 5 inhibitor, tadalafil and 2 alpha-blockers, doxazosin and tamsulosin in healthy normotensive men With tamsulosin (Flomax), 10 or 20 mg tadalafil caused little extra drop and no one fell below 85.15PubMed. Interaction between the phosphodiesterase 5 inhibitor, tadalafil and 2 alpha-blockers, doxazosin and tamsulosin in healthy normotensive men
The name on your bottle matters: doxazosin and tamsulosin act differently on blood pressure and are not interchangeable here. If you don’t remember which one you take, check the label. Even with tamsulosin, a doctor should decide on any dose above 5 mg.
Kidneys and liver also set limits. With mild or moderate kidney problems, the body ends up with about twice as much tadalafil from the same dose.16PubMed Central. Effects of gender, age, diabetes mellitus and renal and hepatic impairment on tadalafil pharmacokinetics Men with moderate kidney problems should start at 5 mg and take no more than 10 mg once every 48 hours.17Journal of Clinical Pharmacology. CIALIS (tadalafil) tablets Two tablets fit that limit only if it is not repeated within 48 hours. With severe kidney disease or dialysis, the limit is 5 mg once a day, which rules out two tablets.18Journal of Clinical Pharmacology. CIALIS (tadalafil) tablets With mild or moderate liver disease, the dose should not exceed 10 mg, so a doctor should confirm that two tablets is the right amount; tadalafil is not recommended with severe liver disease.19Journal of Clinical Pharmacology. CIALIS (tadalafil) tablets
Some medicines, such as certain antifungals, HIV drugs and some cancer drugs, block the liver enzyme that clears tadalafil and raise its levels.20PDR. Drug Summary If you take any of these, a 10 mg dose may act like a much larger one, so ask your pharmacist. Drugs like rifampin, an antibiotic, do the opposite and can cut tadalafil levels by 88%, making it work poorly.21PubMed Central. Drug-Drug Interactions in the Management of Patients With Pulmonary Arterial Hypertension
To check your own list before doubling, read each label for “nitrate,” “nitroglycerin” or “isosorbide.” Recreational “poppers” are also nitrates. Ask a pharmacist to run an interaction check, which takes minutes, and name all your prostate and blood pressure pills. Recent kidney blood tests showing reduced function are a reason to ask first. Alcohol lowers blood pressure on its own and can add to dizziness, and heavy drinking makes erections harder.
Signs You Took Too Much
Headache, flushing, stuffy nose, indigestion and back or muscle aches are common and usually pass. Dizziness or fainting, vision changes and prolonged erections are signs of too much drug in the system.22PDR. Drug Summary Symptoms that get worse as the hours pass deserve attention.
Side effects may continue into the next day. Don’t take another dose to “test” whether it was the cause.
If you feel faint after two tablets, sit or lie down right away rather than standing. Later, stand up slowly and drink water. Call emergency services if chest pain or fainting occurs, and tell responders you took tadalafil and when, so they avoid nitrates.
Sudden loss of vision or hearing is a reason to stop and get checked immediately. That can look like a dim, blurry or missing patch in vision in one eye, especially on waking, or sudden hearing loss, sometimes with ringing or dizziness. Tell the clinician you took tadalafil and how much.
An erection lasting more than 4 hours is a medical emergency. One otherwise healthy man had a painful erection for 36 hours after tadalafil and needed surgery to drain it.23Elsevier / Urology. Tadalafil-associated priapism Don’t wait it out. Note the time it began, since the 4 hours are counted from the start, and go to an emergency department once you pass that mark.
Better Options Than Doubling Up
A doctor can switch you to as-needed 10 or 20 mg, or adjust your daily dose, based on your health and other medicines. If you take tadalafil for prostate-related urinary symptoms, 5 mg daily gives the best balance of benefit and side effects, with higher doses adding little.24PubMed. Tadalafil administered once daily for lower urinary tract symptoms secondary to benign prostatic hyperplasia: a dose finding study Those urinary improvements held up over a year of daily use.25PubMed. Tadalafil administered once daily for lower urinary tract symptoms secondary to benign prostatic hyperplasia: a 1-year, open-label extension study Ask whether the daily dose is already helping your erections, since many men get both benefits from the same tablet. A doctor may add a separate plan for sex, but that decision should be made with your medicine list in view.
A prescriber can check your blood pressure, heart health and medicines before choosing a dose. Erection trouble can sometimes be an early sign of heart or blood sugar problems, so a review is worth having for more than the dose.
When you ask for a change, tell the doctor how often you have sex and whether timing matters to you, and whether 5 mg works partly or not at all. Name all your medicines, including alpha-blockers and heart pills, and mention any dizziness or side effects at your current dose.
A switch to as-needed dosing means the doctor stops the daily tablet and gives you a 10 mg tablet to take before sex, no more than once a day. If 10 mg is not enough and you tolerate it, the doctor can raise it to 20 mg. Your daily steady level fades over several days after you stop, so the change doesn’t work instantly.
Cost doesn’t have to push you to improvise. Generic tadalafil bought through discount pharmacy platforms cost about $103 to $496 a year for 20 mg, far below some insurance plan prices.26PubMed. A United States Cross-Sectional Analysis of Annual Out-of-Pocket Cost Disparities of Erectile Dysfunction Medications Comparing prices on a discount card can make a higher-strength prescription affordable. Ask the prescriber whether one 20 mg tablet is cheaper than two smaller ones, since price is not always tied to strength.
Fake erection pills sold online have contained anywhere from none to more than double the stated drug, plus contaminants like talc, paint and printer ink.27PubMed Central. Counterfeit phosphodiesterase type 5 inhibitors pose significant safety risks In one check of tadalafil sold online, half the samples were fake, some containing sildenafil instead, and unlicensed ones contained no active drug at all.28PubMed. Falsified tadalafil tablets distributed in Japan via the internet Use a licensed pharmacy that requires a prescription, and never solve a cost problem by buying from a site that skips one.