Is there a maximum IVIG dose?
September 9, 2017 at 9:06 am
Questions, questions, I have questions ;-). I did search the forums but the best I could find was a 5 year old thread pointing to a 13 year old study…”its spectrum of efficacy, especially as first-line therapy, and the appropriate dose for long-term maintenance therapy are not fully established.”
It is my understanding the current standard is a loading dose of 2 gm/kg over 5 days and future maintenance dosing of 1 gm/kg but that no longer works for me.
Is there a maximum dosage of IVIG that should not be exceeded? If so, is it in terms of grams (or grams per body weight)? Frequency e.g. every 1, 2, 3, 4 weeks or more? Both amount and time? Other? Are side effects the main issue?
I realize my insurance company may have limits in their medical policies for CIDP. I am in the US and wondered if anyone has seen a chart summarizing the FDA approved doses/time frequencies from clinical trials or other studies for the different brands on the market? I assume they do not vary greatly, but do not know.
Are people out there receiving more than FDA approved amounts, assuming they exist, to stabilize their disease?
Here’s why I ask. Every few months my response to IG declines. As that happens, we have either changed the dosage of IG, e.g. + .5 gm/kg, or decreased the time interval e.g. 4 weeks down to 2 weeks. I am in that decline period again but Dr doesn’t want to make more IG changes, concerned I believe, with side effects although I’ve had few, if any, on the brand I am using and tolerating what I gather is a higher infusion rate.
No doubt more questions to follow. Thanks.
September 9, 2017 at 4:57 pm
There is the suggested dose pattern, but I haven’t seen any maximum dose out there (but I’m sure if anyone has a max its your insurance company). The standard is to do the loading dose 2g/kg div 2-5 days, then drop to 1g/kg div 2-5 days typically every 4 weeks. Based on patient response the time usually gets adjusted forwards or backwards first. Based on degree of disease seen during the diagnostic process (EMG, LP, MRI) the doctor may choose to stay at the loading dose longer before dropping down. The amount of flexibility in timing and dose is sadly also affected by insurance. Based on clinical response after 3-6 months doctors will either stick with IVIG (assuming positive results they will keep trying to dial it in to find an ideal pattern, add steroids with the IVIG for added benefit, or change brands of the IVIG of there seems to be less benefit than expected or more negative side effects than expected), or leave IVIG to try Plasmapheresis (especially if symptoms are continuing to worsen), convert to subcutaneous IVIG (especially if IVIG is showing benefit but too many negative side effects, or too much of a rollercoaster between infusions, since this is meant to be used about once a week at home), or trying immunosuppressants (such as Rituxan).
I have had benefit from IVIG. However the area of nerve damage in my body keeps spreading, like we haven’t yet caught up to the speed of the disease. I was approved to do the loading dose level every four weeks for the first year by my insurance. At the six month mark I can tell that I start significantly relapsing at the start of that third week, but because of insurance we can’t push it forward to match my crash. What we tried this month was starting my IVIG with 2g of Solumedrol to try to get an extra jump on the worsening symptoms. If this doesn’t work, my Neuro wants to try it one more month with Solumedrol again and then take a break from IVIG to do an inpatient round of Plasmapheresis for 5-10 days. He indicated his preference is to then return to IVIG. If it still fails then he will discuss staying on Plasmapheresis longer (for some patients indefinitely).
So there are still options for you and your dr to discuss. If IVIG has made improvements, I’d probably try a steroid booster first and a brand switch second. If still no meaningful difference I’d probably try subcutaneous next if I felt like IVIG was still helping me but it’s just not able to be done soon enough between infusions to keep me feeling leveled between infusions. If, though, I felt like my symptoms of nerve damage were spreading in severe or widespread ways (such as having bladder, colon, stomach, swallowing issues; or significant difficult using all four limbs) I’d advocate for Plasmapheresis until things improve enough to return to IVIG. If your Neuro isn’t aware of the other options, or unwilling to provide them, it may be time for a second opinion with someone else who has more experience with these non-IVIG options.
September 9, 2017 at 9:25 pm
Dr keeps throwing Prednisone changes in when the IG quits being as effective, but I cant tell it helps a lot and I have side effects from sleep issues, vision blurring, eye pressure, blood sugar (now diabetes), etc. Ive been at rather high doses at times e.g 60mg+ daily for long periods.
.Started loading IG dose 2gm/kg (in-patient 5 days) followed by 1 gm/kg at 4 weeks.
.6-8 months later moved to 2 gm/kg at 4 weeks.
.3-4 months later to 1 gm/kg at 2 weeks and then
.3-4 months later to 1.5 gm/kg at 2 weeks.
.3 months later its not holding now much beyond week one.
Dr had mentioned IG brand switch once before but last mentioned PlEx although after research it doesnt sound as easy and straightforward as described plus a major inconvenience repeating inpatient stays 2 weeks at a time. Id rather try IG brand switch or higher dosage hence my question.
I also cant find strong indications the PlEx will do better than IG but will discuss with Dr.
September 10, 2017 at 12:05 am
Sometimes plasma exchange is the better treatment. I had two loading doses of IvIg, but continued to decline. I was switched to plex, but had pretty much bottomed out by then. I had nine exchanges over a three week period. I was already in hospital, so that wasn’t a concern. I have never had IvIg again and have recovered to about 95% of normal.
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