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Featured Cialis Daily vs Regular Cialis - Efficacy Discussion

Discussion in 'Erectile Dysfunction Forum (Viagra/Cialis)' started by Rich2222, Sep 16, 2013.

  1. Rich2222

    Rich2222 Member

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    What are your opinions about cialis daily vs 'as needed' on-demand regular cialis?

    I have been trying different doses and timings of Cialis and noting side effects, effectiveness and response times, because I want to understand what works best for me and then work out a method to achieve a consistent level.

    I can see that some people say that the smaller daily dose is best, others that 3 x 10mg tablets per week is recommended by some urologists. I know that taking Cialis as required is not going to work for me because it seems to take some time to become effective in my system.

    I have a technical question about the half life of Cialis that will probably only be of interest to a chemist, or even a mathematician...

    I understand the theory of half life (e.g 50% Cialis effective after 17.5 hours), but I am trying to find the formula that can calculate the residual % after 'X' hours because looking at the graphs it is not a linear ration (i.e not 75% effective after 8.75 hours). With this I will be able to set up a schedule to provide the level of 'background' Tadafil that will suit my needs.

    Can anyone point me in the right direction ? - I haven't found anything that makes sense to me in my internet searches to date.
     
  2. Medic

    Medic Administrator

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    RE: Cialis Half Life - Technical Question

    Hey Rich

    First of all, really happy to see such an interesting question. I am not a GP or a scientist, but I remember pondering over this couple of years back and managed to get around to a graph released by Lilly.
    cialis-vs-cialis-daily.jpg

    Let me conclude what I see:
    1. 20mg cialis(tadalafil) dose reaches peak plasma concentration at 2 hours.

    2. It looks like the high plasma concentration is maintained from the timeline 2h-6h.

    3. 30% is lost after 12 hours and 50% is lost around 17.5 hours. This is consistent with a lot of the articles we have read.

    4. Interestingly about 20% is still left in the system after 48 hours although they dont claim it is effective(from all the press and research) after that period. So it appears, the parent company is saying there needs to be atleast 30% plasma(with 20mg dose) concentration in the body or 100 ug/l for most people to get significant benefit.

    5. By the above counts - 5mg on its own as a single dose will do little. But when had daily, it works more like a 10mg single dose from what I can see.

    Would love to get your views on this :)
     
  3. danny

    danny Member

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    RE: Cialis Half Life - Technical Question

    Hmm... This should explain why I feel like its still helping me a bit on the 3rd day.

    I considered the daily dose, but was not sure if the medication would lose its effectiveness after a few years if taken like that.
     
  4. Rich2222

    Rich2222 Member

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    RE: Cialis Half Life - Technical Question

    Still digesting your comments, but here's a few comments.

    1) Did you extract the numbers from the Lilly chart - if so your eyesight is a damn sight better than mine - or did you find the numbers behind it? I couldn't find anything on the Lilly site.

    2) I am interested in the word "effective" both in terms of the definition (surely will mean different things to different people. so clinically how is that defined?) and the 48 hour window (I have never seen this in my investigations - can you expand?).

    3) I am interested in the minimum effective level and how the "as required" use of Cialis differs from the "daily dose".
    The effective Cialis in the blood for a 20mg tablet (even if only for the timeline 2h-6h) is significantly higher than for someone taking the daily dose of (for example) 2.5mg, and yet a lot of people take the daily dose and get on very well with it.
    By my calculations, the mean % for daily 2.5mg would be not a million miles away from a 20mg dose after 48 hours............
    So how much needs to be in the system to be effective ?
    Maybe the low daily dose works for people who need only a small push?
     
  5. Medic

    Medic Administrator

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    RE: Cialis Half Life - Technical Question

    Well, yes I visually plotted from the lilly graph I embedded in my previous post :)
    source of graph: http://pi.lilly.com/us/cialis-pi.pdf

    Well, we both know - Lilly says the standard cialis dose(20mg I assume) is effective upto 36 hours. So no reason to assume anything else. They obviously arrived at this number from their numerous clinical trials. Medical research efficacy definitions are laid out from a lot of clinical trial results - so if 70% of people say its effective for this time - then that stays.

    The 20mg cialis takes more than 3 days to leave the body completely. Every credible graph shows this. See the graph above - at 48 hours there's still around 60ug/l (20%) left. And I assume, this is the reason why some people say it worked even after 48hours. But it would be reasonable to think it will not work as well after that time period for those of us who need more help or perhaps who have higher resistance to the drug.

    When taken daily, the tadalafil plasma concentration builds in the body. Look at the graph above. Notice the difference btw "one 5 mg dose" and "5mg dose when had daily for 5 days". It seems like it is possible to achieve constant concentration equivalent to a 10mg dose. I am saying this based on the 20mg and 5 mg(daily) plasma concentrations(from the graph) - the 150ug/l peak tadalafil plasma achieved by having the 5mg dose daily is equivalent to half of the peak plasma of 20mg dose and since dosage strength is somewhat proportional to plasma concentrations - that should equal peak effects of 10mg cialis dose.
     
  6. superstump

    superstump Member

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    RE: Cialis Half Life - Technical Question

    Goodness gracious. WTF!
    Medic and Rich2222 need to stop this over-analysis and start having sex :D

    Personally I prefer the 10mg tablet and I find it useful the next night too. The 20mg erects my back more than my penis lol, the side effect is a bitch.
     
  7. rodney

    rodney Member

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    RE: Cialis Half Life - Technical Question

    "WTF" is your problem ? Its nice to see these kind of technical and productive thread here. This place has a lot of cheesy discussions but this is a refreshing and useful topic and one that I am sure many men have.

    Excellent post medic. Your insights about daily cialis makes sense!
     
  8. Lorigh

    Lorigh Member

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    RE: Cialis Half Life - Technical Question

    My hubs had back spasms too...naproxen seems to help.
     
  9. Rich2222

    Rich2222 Member

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    RE: Cialis Half Life - Technical Question


    superstumpsuperstump
    I'm interested in Cialis side effects - I'll start another thread to see where that goes
     
  10. Medic

    Medic Administrator

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    #10 Medic, Sep 26, 2013
    Last edited: Jul 16, 2015
    I have carefully plotted Lilly's data to scale and made an interactive graph at cialis daily research
     
  11. Rich2222

    Rich2222 Member

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    Medic - that's an impressive piece of research and analysis and answers many of my original questions.
    I hope other members find it useful.
     
  12. Roger-That

    Roger-That Member

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    MedicMedic By far the best report on this topic. Very good stuff! My understanding on this topic feels much more useful.
     
  13. walterk

    walterk Rookie

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    Interesting observation. I landed on this forum from that blog post :)
    Especially the part about the timing of the dose. Ace stuff.
     
  14. Rich2222

    Rich2222 Member

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    Here's a thought - if peak levels increase with the daily dose (per the graph and your comments in the excellent blog), I wonder where this reaches a maximum ??

    Does it increase the peak, or perhaps increase the lower levels ? I am not sure the graphical data indicates either.
     
  15. Rich2222

    Rich2222 Member

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    Here's some more for anyone with an interest in how things work (or sometimes don't...) and trying to understand the difference between daily and on-demand usage of Cialis. I stumbled across this study from 2010 called "A once-daily dose of Tadalafil for erectile dysfunction: compliance and efficacy"

    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2939761/pdf/dddt-4-159.pdf

    There are 12 pages of technical reports and it cross references a number of different reviews. With regard to the comparison between Daily and On-Demand, pp161-162 offers this :-

    My own experience is that 10mg on-demand has not been adequate for me, which probably explains why I haven't had much success with a 5mg daily dose when I tried my own experiment.
     
  16. rodney

    rodney Member

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    Rich2222Rich2222
    Thanks for the share. Nice information and according to expected lines.
     
  17. jimjim111

    jimjim111 Rookie

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    Hello, guys. Is cialis 20 mg more efficient than 5 mg? thanks
     
  18. Medic

    Medic Administrator

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    Depends really. Cialis 5mg is a daily dose meant for people who are sexually pretty active and want to maintain steady level of tadalafil in their bloodstream. The 20mg is good to jump start things and used 'as needed' - it is also obviously higher dose.
     
  19. Benoit W

    Benoit W Member

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    I саn sаy thаt I'vе triеd thе сiаlis-оnсе-а-dаy (5mg еvеry dаy, nоt just dаys yоu plаn оn intеrсоursе) аnd hаvе hаd grеаt suссеss with thаt. оnсе yоur оn dаy 5ish I didn't hаvе аny оf thе sidе еffесts I experienced with the 20mg dose and wаs аblе tо gеt аn еrесtiоn еаsily аt аny timе.
     
  20. Alexandoy

    Alexandoy Junior Researcher

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    Honestly, I want to be always ready with my weapon when the situation calls for. It is inconvenient to take cialis when needed because it takes time for the effect to manifest. But I am also afraid of taking drugs regularly for it might have an unforseen side effect. For now I am content with anticipating action so I can take the drug an hour before sex.