I really wish I'd paid more attention to biology & chemistry in school! Learning about the pharmacodynamic & pharmacokinetic properties of medications is truly fascinating. I'm so enamored by the cytochrome P450 family of enzymes & the highly important CYP3A4. 1/ #NEISVoid
There is a long list of drugs which are either substrates, inhibitors and inducers of CYP3A4, which determines how these drugs are metabolised. Grapefruit juice can also inhibit this enzyme, which when coupled with a moderate or strong CYP3A4 inhibitor drug can be dangerous. 2/
While it may not directly cause QT prolongation, combining two drugs (one of which may cause QT prolongation) which are metabolised through this enzyme can lead to increased levels of this drug, increasing the risk. 3/
This does not mean that you can never use 2 inhibtors or two inducers or a combination ever. Given the long list of drugs that use CYP3AR, treatment would be impossible. Considering the potency of inhibition/induction, the risk vs. benefit, with close monitoring would be best. 4/
Going through the EPAR reports published by the EMA is by far the best place to start to understand whether the drug you take is contraindicated with the drug you're considering to add to your regimen or whether a dose adjustment with close monitoring would be an option. 5/
Given that a lot of #LongCovid folks are getting to start Ivabradine or Guanfacine, both of which are CYP3A4 inhibitors, and given that a considerable subset of this population also uses antihistamines for #MCAS and/or LABA inhalers for #asthma, understanding this will be key.
Just some notes: Ivabradine & Desloratadine are both weak inhibitors of CYP3A4. They are neither contraindicated for concomitant use, nor are they requited to be used with precaution. However Ivabradine is not recommended to be used with other QT prolonging medicinal products. 6/
Desloratadine has not shown to have QT prolonging effects in a statistically significant manner in studies but questions do linger, given the history of previous generation antihistamines. Also, these studies do state that the few cases of QT prolongation with desloratadine 7/
occurred in combination with other drugs with QT prolongation effects. To my best knowledge & search (through public sources), there is no study for interaction between the two drugs. Concomitant use should therefore be decided in consultation with a cardiologist. 8/
Personally, the farther away from Ivabradine I take desloratadine, the better I feel. There is indeed a dragging effect when I take them together. Given the half life of Ivabradine (2 hours) and the low dose I take of both drugs, so far it has been okay. I get regular ECGs. 9/
QT correction methods seem to vary (& my cardiologist always does a manual calculation). For men the upper QTc limit seems to be 450 and women 460 (although anything above 450 is shown as QT Prolongation in ECGs & some studies say the limit is 460 & 470 respectively). 10/
I'm not very confident about this part so please take it with a pinch of salt (or lots, if you have #POTS) and discuss with your cardiologist. A QTc of over 500 increases the risk for TdP (the very sexy sounding Torsades de Pointes), a specific type of arrhythmia. 11/
Unless you have congenital LQTS or are on a combination of drugs that can cause QT prolongation but are not sufficiently monitored (even then it seems to be extremely rare), it shouldn't be a problem. However, it is still good to get this cleared with your doctors. 12.

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More from @renudhinakaran

Feb 4
#LongCovid treatment update:
As promised to my fellow #NEISVoid folks, here is a full list of my medicines, supplements, medical devices & rehabilitation in my recovery journey.
1. #POTS (Hyperadrenergic) - Ivabradine, Amlodipine, IV Saline (every 7 to 10 days as needed). 1/
2. #MCAS - Desloratadine, Montelukast, Cromolyn Sodium (Cetrizine + Prednisolone for rescue)
3. Rheumatoid Arthritis - Methotrexate, Paracetamol, Diclofenac Cream
4. #asthma - Budesonide/Formeterol, Ipratropium Bromide, Salbutamol (Rescue) 2/
5. GI issues - Pantoprozol, Prucalopride
6. Eyes - Olapatadin & Cromolyn eye drops, Refresh Tears, Refresh Eye Gel
7. Supplements - Calcium, Vitamins C & D, High Potency B Complex
8. Hypermobility - Braces for shoulders, ribs, wrists, elbows, knees & neck as needed 3/
Read 6 tweets
Oct 19, 2022
"Mommy, sometimes a part of me feels like it would be easier to have a different mommy. Not always and not me fully. Am I hurting you by saying this?" I have been preparing for 2 years to answer this question & I aced it! #parenting in #NEISVoid #LongCovid #motherhood🧵1/n
First, I lightened the mood my saying "believe me, I would like to be a different person as well, in a different body". He smiled immediately.
Next, I acknowledged that his thoughts were perfectly rational & had no malice at all. 2/n
I went on to explain that I was not upset. He simply wants to go on playdates with friends without worrying about infecting mommy & making her more sick, or go eat out in restaurants or not be the only kid in class masking. Any kid would want that, any adult would too! 3/n
Read 11 tweets
Oct 18, 2022
If you have #LongCovid & are married/in a relationship, please sit down and have a chat with your partner - about your symptoms, what you can & cannot do, how they can help you. 1/
Your relationship will be affected. It will change beyond recognition. With some effort though, it can be a good change that will help your recovery & solidify your relationship. 2/
You will be in pain & may not even be able to breathe properly. You will be confused. Please remember, your partner will be too. If they can't understand what you're going though, what you need & what they can do, it is not going to help either of you. 3/
Read 6 tweets
Sep 30, 2022
If you have #LongCovid & live in the Netherlands, here are the things that you are entitled to:
1. Physiotherapy for 6 months to 1 year even if you don't have aanvullendeverzekering (might change from Jan 2023) with home visit.
2. Occupational therapist (with home visit) 1/
3. Trippelstoel (through insurance, with help from OT)
4. Wheelchair and traplift from WMO, if your huisarts & OT give detailed letters supporting it
5. Ask for a referral to a Hartkliniek Cardioloog if #POTS is suspected. 2/
6. Ask for a pulmonoloog & rheumataloog referrals. Insist on an autoimmune panel - UMC Utrecht has post Covid autoimmune specialisations. It is an uphill task but possible.
7. If your 6 minute Walking test is below 92 SpO2, you are entitled to an oxygen concentrator at home. 3/
Read 5 tweets
Sep 28, 2022
On this day last year, on the eve of my husband's birthday, we all felt hopeless. #LongCovid had taken almost everything away from me & I wanted to die. Today, I cooked him his favourite meal & danced with him. I didn't realise how happy we were until I watched this! #NEISvoid 1/
@anandkumarn is a remarkable man. Smart, intelligent, charming, kind to a fault, fiercely protective of his family, a wonderful son & father, a well respected professional. He is the most loving & devoted husband a girl can dream of - a true partner & a prince among men. 2/
He is not faultless, nor is a Saint. He has, however, worked hard to accept his mistakes, learn from them, make amends & be a better man every day. He deserves more happiness than he now has & I will do everything in my power to get there. 3/
Read 5 tweets
May 24, 2022
Stop doing standard tests on #LongCovid patients and claim that they are physically alright because the results are normal. Medicine & Science have not bothered to develop proper biomarkers for post viral illnesses for decades, ignoring the pleas from patients, including #pwme.1/
The world has not seen a pandemic on the scale of what #COVID19 caused (last was the Spanish flu) and by definition, you have not seen mass disability on the scale of what #LongCovid has been causing. Use your brains and empathy - if you have either of them - & think! 2/
Why would millions of people sit at home, losing their appetites, mobility, health, livelihood (and lives, sadly, in some cases) after contracting Covid without an actual biological/physical cause? They cannot all be depressed, surely? 3/
Read 9 tweets

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