Metoprolol XL 400 mg QD?????

[Sparda29]

Has anyone ever seen this dose being used in community practice? We got a prescription for a patient for Metoprolol XL 400 mg QD. First off, it doesn't even come in 400 mg, so my first thought was that maybe the MD wants 200 mg BID. Still sounded like a really high dose to me so we ended up calling the MD.

The patient was originally taking regular Metoprolol tartate 100 mg TID, and they wanted to increase the dosage to Metoprolol tartate 100 mg QID, instead of doing that, they decided that they would rather give Metoprolol Succinate (XL) 400 mg QD. After talking to the MD, they said just do Toprol XL 200 mg, 2T QD.

So here is my question, when switching from Lopressor to Toprol XL, isn't there some sort dose conversion that ends up with the dose being lower in the Toprol XL dose?

Asides from that, we know that the patient has asthma. We don't know if she's had a heart attack before (but I do know that beta-blockers have that cardio-protective properties). Despite telling the doctor this, she insisted on giving the high dose, so we documented this all and filled it.

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[ForcedEntry]

400mg/day is max, so you could do it, but probably not the best choice in the world. As you know the closer you get to max dose, the more the Pt is exposed to SE.

BBlock suck anyway. I know they are first line by 2007 AHA, but it is a little hard to recommend a HTN Pt to increase their exercise w/ BB Tx.

Does the Pt have a CI to ACEI w/ or w/o HCTZ or CCB?

 

[Sparda29]

400mg/day is max, so you could do it, but probably not the best choice in the world. As you know the closer you get to max dose, the more the Pt is exposed to SE.

BBlock suck anyway. I know they are first line by 2007 AHA, but it is a little hard to recommend a HTN Pt to increase their exercise w/ BB Tx.

Does the Pt have a CI to ACEI w/ or w/o HCTZ or CCB?

I don't remember exactly, but I've seen this patient come to our pharmacy for years, and shes on multiple medications. I know she is on an ARB/HCTZ combo as well as a CCB. Also takes insulin as well as other diabetes medications, and medications for hyperlipidemia.

 

[ForcedEntry]

Ahhh...the classic cocktail

 

[Farmercyst]

If I remember correctly Toprol XL should be BID because of saturable kinetics. With Tartrate you saturate, with XL you don't so your clearance is actually higher and should be dosed more frequently for a better effect. Since she appears tx resistant, it might have been better to do BID, but hey, I'm just a P3, what do I know.

 

[Praziquantel86]

If I remember correctly Toprol XL should be BID because of saturable kinetics. With Tartrate you saturate, with XL you don't so your clearance is actually higher and should be dosed more frequently for a better effect. Since she appears tx resistant, it might have been better to do BID, but hey, I'm just a P3, what do I know.

I remember something similar.

OP: Have you asked her what she's using it for? If she's using it for post-MI cardioprotection, or she's in early heart failure, the dose isn't too unbelievable. Some cardiologists take a very aggressive approach, especially in high-risk patients (which she sounds like she is).

If it's for hypertension, then that's where the problem is. Unless she's maxed out on all her other antihypertensives and they're just trying the kitchen sink, a dose that high would just increase the risk of serious-ADRs with not too much additive benefit.

If you're not able to get a good answer from the patient, give the doc a call (if he seems like the type that would answer a few questions). Just tell him you're a student, and you're interested in learning. Either he'll give you a straight answer or tell you to piss off, but it can't hurt to try.

 

[smileyangel11]

Asides from that, we know that the patient has asthma. We don't know if she's had a heart attack before (but I do know that beta-blockers have that cardio-protective properties). Despite telling the doctor this, she insisted on giving the high dose, so we documented this all and filled it.

If I remember right, metoprolol becomes non-beta selective after 200 mg daily doses. Thus, I would suggest her to also watch her asthma symptoms. One our cardiologists educate all her residents on beta blockers & asthma because she had an asthma exacerbation after starting herself on atenolol for HTN.

 

[Sparda29]

I remember something similar.

OP: Have you asked her what she's using it for? If she's using it for post-MI cardioprotection, or she's in early heart failure, the dose isn't too unbelievable. Some cardiologists take a very aggressive approach, especially in high-risk patients (which she sounds like she is).

If it's for hypertension, then that's where the problem is. Unless she's maxed out on all her other antihypertensives and they're just trying the kitchen sink, a dose that high would just increase the risk of serious-ADRs with not too much additive benefit.

If you're not able to get a good answer from the patient, give the doc a call (if he seems like the type that would answer a few questions). Just tell him you're a student, and you're interested in learning. Either he'll give you a straight answer or tell you to piss off, but it can't hurt to try.

See that's the problem. She doesn't have one doctor, or one cardiologist that she sees. She goes to a low income clinic at the county hospitals, and every week we get a prescription from a different resident.

 

[Old Timer]

See that's the problem. She doesn't have one doctor, or one cardiologist that she sees. She goes to a low income clinic at the county hospitals, and every week we get a prescription from a different resident.

Than you really DO NEED to intervene on behalf of your patient and to protect yourself. There are serious issues not the least of which is an exacerbation of her asthma which could lead to hospitalization. The other is any of the myriad of ADR's she could encounter at the max dose of 400mg.

Make the call, what's the worst that happens, you get your ass chewed out. Best case either you learn something new or you helped a patient prevent a serious ADR. This is your career. Start now. This is CLINICAL Pharmacy in the community setting. The only thing that keeps many poor patients from getting ADR's is you.

 

[Sparda29]

Than you really DO NEED to intervene on behalf of your patient and to protect yourself. There are serious issues not the least of which is an exacerbation of her asthma which could lead to hospitalization. The other is any of the myriad of ADR's she could encounter at the max dose of 400mg.

Make the call, what's the worst that happens, you get your ass chewed out. Best case either you learn something new or you helped a patient prevent a serious ADR. This is your career. Start now. This is CLINICAL Pharmacy in the community setting. The only thing that keeps many poor patients from getting ADR's is you.

So we actually managed to track down one of the residents that writes her prescriptions. Since she's the senior resident, we're going only going to use her when it comes to questions about this patient.

After telling her about the high dose, relation to asthma and whatnot, she decided to keep her on the high dose. I was thinking, if you're trying to get a better benefit for BP issues, increase the dose on her other BP meds, not the beta-blockers.

 

[atpsynthase]

I hate to resurrect this thread, but it got me thinking about metoprolol kinetics. I don't remember learning a whole lot of specifics during school. I've been combing through literature and I haven't really been able to find a concise article regarding the specific PK/PD differences between the two formulations and dosing implications. Anyone have any friendly articles addressing metoprolol?

I certainly know the general differences in the formulations and concepts of ER vs IR, etc., but I'm trying to supplement my knowledge to try and understand more of the obscure dosing situations... any input would also be welcome.

Ex: metoprolol tartrate TID to reduce chance of losing beta1 selectivity? metoprolol succinate BID to reduce orthostatic HoTN?

 

[maria1oh]

If she's poor can she even afford the XL? The tartrate is a $4 generic but the XL is pretty expensive.

 

[Sparda29]

If she's poor can she even afford the XL? The tartrate is a $4 generic but the XL is pretty expensive.

Medicaid covers Toprol XL generic.

 

[PharMed2016]

It would make more sense to me to split the dose in half and do BID dosing. It would help with the beta selectivity issue theoretically. Metoprolol tartrate has a t0.5 of 3-4 hours vs succinate 5-7 hours. However, I have seen 400mg dose before when I was on the cardiology service for ischemic cardiomyopathy/HF. Decreases the risk of a fatal arrhythmia or infarct along with remodeling.