2.5mg of dutasteride reaching a steady state?
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hair today gone tomorrow
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about 6 days at 2.5 mg a day about 10 days at 1.5 mg a day.
blaze
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Im talking about 2.5mg reaching its peak DHT inhibition levels, Im not using a loading dose of 2.5mg only to taper back to 0.5mg per day.
Im talking about 2.5mg per day as a regular dose - no tapering back. How long would that take to reach a steady state?
Im talking about 2.5mg per day as a regular dose - no tapering back. How long would that take to reach a steady state?
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blaze said:
Check out the following graph from the Gisleskog et al studies on dutasteride:
http://www.geocities.com/bryan50001/dutasteride3.htm
I personally penciled-in the dashed vertical line corresponding to a daily dose of 0.5 mg (Avodart).
As you can see from the graph, a daily dose of 2.5 mg is well into the "flat" portion of the curves, indicating that it would take about 44 days to achieve 70% of steady-state, about 84 days to achieve 90% of steady-state, and about 110 days to achieve 95% of steady-state.
blaze
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thanks Bryan. I was hoping you would show up.
I forgot to mention I have already been taking 0.5mg for 2 months and then 1mg of dutasteride per day for 2.5 months, and am now upping my dose to 2.5mg per day.
I assume that would make my reaching a steady state with 2.5mg a little quicker?
I forgot to mention I have already been taking 0.5mg for 2 months and then 1mg of dutasteride per day for 2.5 months, and am now upping my dose to 2.5mg per day.
I assume that would make my reaching a steady state with 2.5mg a little quicker?
hair today gone tomorrow
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so there is no difference in taking 1 mg or 10 mg? it will take the same amount of time to reach SS inhibition levels?
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thomas040 said:yeah... the time it takes for dutasteride to reach most DHT blocking...
I'd prefer to be just a tad more precise: "steady-state" is the maximum steady level of the drug in your bloodstream, after you've been taking some specified dose for a long long time.
The exact steady-state level will vary with the dose, obviously, and the time that it takes to get there will also vary somewhat, at least at lower doses. At dosage levels above about 1 mg/day or so and higher, it takes about the same amount of time to hit steady-state, as you can see from that graph.
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Here, take a look at another of my Gisleskog et al studies:
http://www.geocities.com/bryan50001/dutasteride2.htm
Scroll down slightly to graph B, "Proportion of Baseline 5AR1 Activity". They only have curves for three different dutasteride doses: 0.1 mg/day, 1 mg/day, and 10 mg/day, so you'll have to interpolate a little between the 1.0 mg and 10 mg doses to try to get a "guesstimate" for what a 2.5 mg dose will do. That would lie in between the short-dashed line (1 mg) and the dotted line (10 mg).
Also, keep in mind that the doses in that graph run for only 28 days. It takes longer than that to reach steady-state, so you also have to mentally extend the curves a little to "guesstimate" the final suppressive effect!
http://www.geocities.com/bryan50001/dutasteride2.htm
Scroll down slightly to graph B, "Proportion of Baseline 5AR1 Activity". They only have curves for three different dutasteride doses: 0.1 mg/day, 1 mg/day, and 10 mg/day, so you'll have to interpolate a little between the 1.0 mg and 10 mg doses to try to get a "guesstimate" for what a 2.5 mg dose will do. That would lie in between the short-dashed line (1 mg) and the dotted line (10 mg).
Also, keep in mind that the doses in that graph run for only 28 days. It takes longer than that to reach steady-state, so you also have to mentally extend the curves a little to "guesstimate" the final suppressive effect!
blaze
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Thanks for that graph and explaination bryan.
The only problem is that 2.5mg and 5.0mg(from what I have read) seem to be very similar in regards to their inhibition rates. I dont even think 10mg made much difference. I found it very hard to interpolate due to this.
10mg after 28 days looks to inhibit around 92%. It may get to 95% when it reaches a steady state.
Since there is not much difference between 2.5mg and 5.0mg per day, I'd say that 2.5mg per day would probably inhibit around 85% type 1 5AR.
Does that sound right to you Bryan?
The only problem is that 2.5mg and 5.0mg(from what I have read) seem to be very similar in regards to their inhibition rates. I dont even think 10mg made much difference. I found it very hard to interpolate due to this.
10mg after 28 days looks to inhibit around 92%. It may get to 95% when it reaches a steady state.
Since there is not much difference between 2.5mg and 5.0mg per day, I'd say that 2.5mg per day would probably inhibit around 85% type 1 5AR.
Does that sound right to you Bryan?
hair today gone tomorrow
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Bryan said:
if that is the case why are some studies having guys taking a loading dose of 2.5mg if it wouldnt get you to SS any quicker than 1mg would?
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blaze said:
For inhibition of type 1? Where'd you read that?
blaze said:
At those large doses, inhibition of type 2 is virtually TOTAL. All that's left is the inhibition of type 1, which is starting to approach 100%.
blaze said:
Agreed.
blaze said:
That seems a little high to me, but who knows for sure...
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hair today gone tomorrow said:
if that is the case why are some studies having guys taking a loading dose of 2.5mg if it wouldnt get you to SS any quicker than 1mg would?[/quote:25866]
You have to clarify which SS you're talking about!
Taking 2.5 mg/day for a few days will obviously get you to the normal 0.5 mg/day SS faster than if you were to take only 0.5 mg/day from the very start, but getting to the 2.5 mg/day SS by taking 2.5 mg/day will take exactly as long as it takes to get to the 10 mg/day SS by taking 10 mg/day.
hair today gone tomorrow
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Bryan said:
You have to clarify which SS you're talking about!
Taking 2.5 mg/day for a few days will obviously get you to the normal 0.5 mg/day SS faster than if you were to take only 0.5 mg/day from the very start, but getting to the 2.5 mg/day SS by taking 2.5 mg/day will take exactly as long as it takes to get to the 10 mg/day SS by taking 10 mg/day.[/quote]
oh ok, i understand now....well whats the "highest" possible SS you can attain? would that be at 2.5mg? I mean it has to plateau at some point.
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hair today gone tomorrow said:
It doesn't plateau at any point. It's proportional to the dose. The more you take, the higher the blood level.
At higher levels (like around 1 mg/day and above), the steady-state level is almost DIRECTLY proportional to the dose. In other words, doubling the dose approximately doubles the steady-state blood level. At lower doses (like 0.1 mg/day, for example), doubling the dose has an even GREATER effect on steady-state levels, because of dutasteride's non-linear elimination characteristics.
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Bryan said:
In fact, I should mention here that there was even a vague possibility that blood levels of dutasteride could conceivably start to accumulate without any limit at all, once you get above a certain dosage level. Here's a brief comment on that, near the end of one of the Gisleskog et al studies:
"Even though a major nonlinearity exists in the elimination of GI198745 [dutasteride], the presence of a linear elimination pathway ensures that unlimited accumulation will not take place."