yea grapefruit juice is contraindicated for many many drugs.
Grapefruit juice is metabolized by an enzyme in the liver that also is responsible for breaking down many medications. With grapefruit juice in your system that enzyme becomes too busy to break down so medications will become more potent and stay in your system longer.
Thanks, that may be the reason my shift to Atenolol from Metoprolol seemed to require a lower dose. I haven't eaten grapefruit for a few days and it appears my side-effects from Atenolol have subsided.
I will continue to take a slightly lower dose, now at 25 mg morning 12.5 mg night, then go back to the 25 mg morning and night. As discussed in another post by me on the BB subject I was experiencing very low HR when in bed, and some serious dizziness.
How are ya goin' mate? Good to see that you're still with us. I take atenalol and it makes me very tired and a bit more dopey than usual (wife claims), also upsets my stomach but it's a heck of a lot better than having those SVT's and has reduced the frequency and severity significantly. What are you s side affects? I take 1/2 25 mg tablet in the morning and sometimes if I have a busy or really stressful day, another 1/4 tab before bed.
I've heard about the grapefruit, but I hate it so have never bothered to look into it. Had the first 'turn' for a long time today, came on as it does with a sudden dizzyness, adrenalin rush, and out of gear the ticker jumped. We were in the food court at the shopping centre having our Thursday once a week dinner out, and it lasted for about 1/2 hour.
I take a 5mg valium, 1/2 of a 25mg tenormin and two tums because it seems to start in my stomach. Since I've been taking the atenalol regularly, ( a couple of years or more) when I do have an SVT my heart rate is a lot slower than it used to be - used to go to 220 but now maybe 120 but I feel the pressure in my ears and a bit 'puffy' and nauseus. Just bad.
Anyway, it decided to go away again, and apart from being tired and washed out I'm OK again.
A funny thing is that now I only have them occasionally when under great pressure I get a lot more freaked out and shake, sweat and feel terrified just like I did when they first started, whereas I used to cope better when I had them weekly or so. Power of the mind eh? If only we could control it.
Cheers from down under. Kev
If you haven't read: ( this thread:
it has some of my experience with a change from Metoprolol to Atenolol. I'll not try to repeat it all here, bet it would come out different anyway : (
As for Grapefruit, it is the worse but not only juice that causes problems. I had read as "itdood" shares with us the problem is related to enzyme conflicts, the liver. I understand that will reduce the efficiency - not enough enzyme resource available to activate the BB, or CCB. But, while itdood says that can cause the does to become an overdose. This is what I seemed to experience in the first day at 25 mg twice a day. But I have also read that grapefruit will reduce the meds, i.e., like too low a dose. I can check again but that's what I recall.
The above thread tracks with some painful detail that I am finding that my body may be adjusting to the Atenolol, and while I am now testing at 25 and 12.5 per day, I will in a couple of days go back to the 25 twice a day and see what happens.
I have only minor dizziness at the 37.5 mg total per day.
Another post of mine explores my experience with a Oximeter that I purchased, and it makes it fast and accurate to check my heart rate. That is also mentioned in various places in my posts. Using that I had found my switch to Atenolol caused low HR, when I awoke in the wee hours of the morning and checked I saw low 50s for a HR - have to check my notes, but think I may have been a high 40s. This translated to low, for me, awake HR and I think was at the root of dizziness problem... the HR was also slow to rise when I stood up and started to walk.
I also believe Atenolol is better at Not interfering with one's brain (dopey) than most other BB, Metoprolol for example.
Well there I go again, I give you a reference to save on typing (typos) and I just keep typing. You should still find some numbers if you look at the reference link given above.
Grapefruit is inhibiting the CYP 3A4 enzyme, which is used to metabolize lots of medications. Metoprolol is inhibited by the CYP 2D6 enzyme, which is inhibited by many other medications (among others most SSRIs, except Zoloft)
The danger with grapefruit and especially grapefruit juice (as you can easily drink juice equal to 6-7 grapefruits) is the combination with antiarrhythmics causing a prolonged QT interval, which have very narrow therapeutical windows (low difference between dosage and overdosage) or other substances prolonging the QT interval (certain antibiotics, etc.), if those are metabolized by the CYP 3A4 enzyme.
I would not think that eating a few slices of grapefruit would be dangerous combined with CCBs or beta blockers. But as always, it's your body, and of course, your doctor knows best.
Regarding the Atenolol vs Metoprolol, Atenolol has no extended release formula, so the effect hits more immediately than what is the case with Metoprolol. On the other hand, half life is far longer (I believe I've commented this on another post). When taking Metoprolol 25 mg, it resolves through 20 hours and the peak "concentration" (compared to taking a non-extended release pill) will be approx. 6 mg. Roughly like this:
Time Intake Concentration
8 1,25 1,1
9 1,25 1,9
10 1,25 2,7
11 1,25 3,3
12 1,25 3,8
13 1,25 4,2
14 1,25 4,5
15 1,25 4,8
16 1,25 5,0
17 1,25 5,2
18 1,25 5,4
19 1,25 5,5
20 1,25 5,7
21 1,25 5,8
22 1,25 5,8
23 1,25 5,9
24 1,25 6,0
1 1,25 6,0
2 1,25 6,0
3 1,25 6,1
4 1,25 6,1
With Atenolol 25 mg, it's more like this:
Time Intake Concentration
8 25 22,9
9 0 20,9
10 0 19,2
11 0 17,5
12 0 16,0
13 0 14,7
14 0 13,4
15 0 12,3
16 0 11,2
17 0 10,3
18 0 9,4
19 0 8,6
20 0 7,9
21 0 7,2
22 0 6,6
23 0 6,0
24 0 5,5
1 0 5,1
2 0 4,6
3 0 4,2
4 0 3,9
Hope this made some sense, at least :-)
Sorry for using European time. 8 is 8 AM and 20 is 8 PM :)
Thanks for the time standard used, but I am still confused by what the numbers between commas means, some being time, but for example in the first entry what does "81" "25 1" and "1" each mean?
The second list, for Atenolol has only two fields per line, so I can't even map a line-per to the Metoprolol.
My Metoprolol is also regular (was) Tartarate (not sue I got the "T" word right).
Sorry for the confusion on my part.
It was your good input on longer half life and less brain affects of Atenolol that encouraged me to ask my Cardiologist to let me give the Atenolol a try.
So far I like the result, and as said I think I will be going back to the prescribed dose, 25 mg morning and evening.
Sorry, I made the calculation in an Excel document, the copy+paste function to the forum failed a bit.
It's supposed to be 8 - 1,25 - 1,1, meaning 8AM - 1,25 mg intake (because 25 mg is released evenly through 20 hours) 1,1 mg is the effective concentration at that given time. It's lower due to the half-life and I've extrapolated the half life to count each hour. At approx. 20 hours you reach "steady state".
Regarding Metoprolol vs Atenolol, I believe all Metoprolol is sold as Metoprolol Tartrate, but it depends if you take the extended release version or not. I know in Norway, you can get both, but I would not exaggerate if I said that 99% is sold in the extended release version. The drug is the same - but in extended release the pills/capsules are made to slowly release the active substance. The non-extended release formula is mostly used to handle hypertensive emergencies or acute arrhythmias, I think.
Atenolol has longer half-life, but to compensate for a short half-life of Metoprolol, the extended release pills are made. But to complicate things a bit further, beta blockers may have effects even after the substance is metabolized, especially regarding blood pressure (due to the effect on salt and fluid balance and production of renin). I would not assume this would be the case with arrhythmias. But as long as you are taking the beta blocker twice a day, I would think the effect would be excellent.
Unless your doctor tell you otherwise, I would still enjoy an orange :-) I drink three cups of orange juice a day while taking Metoprolol and I have no problems. Verapamil is metabolized by CYP3A4 though, so you may want to ask your doctor about excess grapefruit intake. A slice should as far as I know be OK, but again, I'm no doctor.
Sorry for spamming. It should say "but half life depends if you take the extended release version or not". All metoprolol is tartrate as far as I know.
Yes, I was taking Metoprolol Tartrate, at my request. The SR version was in the range of $60US for 90, while the Tartrate (in my case using 1/2 does twice a day) is $15 for 180 pills, thus each serves approximately 3 months. This is not a budget breaker, but I always go for the lower cost if I can't see any real benefit. For me taking twice a day verses once a day is no difference.
If I read correctly the Atenolol holds up fairly well for 20 hours. When I was trialing a single 25 mg in the morning, I did notice a higher, but not dangerous, HR in that period after about 12 hours, surely by 18 hours. That's when I added a half dose at bed time. That helped level the HR out.
I think limes are also on the list of no-no's.
Limes are rare in my diet, but I regularly use concentrated lemon juice (the bottled stuff) in my morning cup of tea. I suppose I use 1/2 oz, so only a fraction (maybe 1/8th) of a whole lemon - which if in my refrigerator I sometimes us, just a slice.
I draw some comfort that eating 1/2 of a fresh grapefruit many not be a problem, but stay away from a glass full. My wife regularly eats grapefruit, thus the temptation for me, when in season. She is on a long list of meds for depression, anxiety, and cancer - so I have asked her to discuss with her doctor(s).
Given the possible dyer results I am disappointed my doctors don't have this warning on the "check list". Whenever I go to my cardiologist or my primary care I am always subjected to a list of questions about my health, none mention grapefruit, or any fruit juice concerns.
My wife is on Tenormin for AF and also warfarin, and for the past few months Femara because she has breast cancer. They say Grapefruit juice has an affect on her INR and they recommend not to eat it, but haven't heard anything about a reaction to tenormin. She is of german origin, so naturally ignores everything and drinks a glass of grapefruit juice each morning. Doesn't seem to have had any measurable affect on anything.
as i said earlier I take 25mg atenalol when I get up in the morning and find that most days that keeps my heartrate fairly stable. If I have a strenuous day I sometimes take just 1/4 tablet at bedtime (12.5mg) as a 'top up' and that seems to agree with me. 25mg twice a day would make me too tired.
Forgot to mention (and ask) that I have dreams everynight, and I mean every night. Always about the past, sometimes re living my time as a police officer when I was young, and more often most of my working life which was an electrical engineer with my own company. The dreams are regular and totally realistic, as though I'm watching a movie of it all. And they are in colour.
Atenalol? anybody else?
You may find something useful on this post, regarding dreams.
Part of my motivation for switching to Atenolol is it has less impact on the brain, and possibly dreams.
As in the above post you can find my dreams have a similar connection to yours in being from the past, but mine are troubled, and therefore no fun. I would like to stop having them. I do not see any reduction in dreaming after my switch to Atenolol, which has now been almost two weeks.
Thanks you so much for posting your comment about the drug interactions between metoprolol and grapefruit! My fiance wanted to eat a grapefruit and I remembered a reaction between the two...thank goodness for your help!!
You are welcome, I'm happy I could help. .
That's why we all post and reply, to look for answers and to offer what we know as patients dealing with heart rhythm problems. .
Yes, I have dreams almost every night especially if I get 7-8 hours of sleep. I was told this would happen, "crazy dreams", so in the beginning I told myself not to fear anything crazy, take it as it comes. Since then 99% of my dreams have been joyous, family related, fantasy stuff, lots of loving females in my dreams and yes some real life stuff too. I hope it keeps going like this. I try to awake refreshed every morning by getting enough sleep, going to bed by 10PM.
Forgot to mention I take 50Mg Metoprolol for since late 2010...3 1/2 years.
So the dreams always happen, 99% joyful thank goodness.
The metoprolol keeps my BP down successfully thank goodness. Had trouble with Lisinopril, Amlodipine, Doxazosin previously - would not work. I keep walking, and going to the gym 3x's a week, try to build muscle.
I'm 59 1/2.
Congratulations, seems have taken charge of dreaming, of having Lucid Dreams... perhaps a subject you are aware of.
This subject has been offered many times by me on "Sleep Disorders". I recommend reading the book by Stephen Deberge (think I have the name right) at Stanford. His book Lucid Dreaming includes an audio CD which I listened to repeatedly. One goal is to get something out of the dreams, get more live-per-year (e.g., miles per gallon) by making use of sleep time. His approach also offers getting more out of awake time simply by being more aware of your surroundings. This last part reminds me of how nature photography works, seeing more so a good picture can be captured. Seeing than color and shape, seeing texture and shading and perspective... more...