Atorvastatin Pharmacology

On this episode, I discuss atorvastatin pharmacology, adverse effects, monitoring parameters, and drug interactions.

Atorvastatin (Lipitor) is an HMG-CoA reductase inhibitor, the rate-limiting step in the production of cholesterol. It is used to prevent atherosclerotic cardiovascular diseases by decreasing cholesterol.

Atorvastatin is more lipophilic in comparison to other statins such as rosuvastatin. If a patient does not tolerate a statin, switching from a lipophilic to a hydrophilic or vice versa may decrease the chances of those side effects reoccurring.

It can be a high-intensity statin depending on the dose. 10-20mg is considered moderate and 40-80mg is classified as high intensity. Not all statins can reach high-intensity doses, which is why atorvastatin is so commonly used.            

The FDA as of July 2021, has requested to remove the contraindication of pregnancy from the prescribing information. Here’s more information on that specific change and why it was requested. I’d encourage you to read it. 

Atorvastatin is commonly found to have adherence issues so it should be taken whenever it is going to be best remembered by the patient.

Common adverse effects include myopathy, muscle pain, and soreness. Many elderly patients can be overlooked when they experience aches and pains, so it is important to take their medications into consideration. There are rare risks of liver injury and rhabdomyolysis. CPK and LFTs do not need to be regularly monitored if no symptoms are present.  

Remind patients that their cholesterol will not be lowered right away. They will usually have their levels rechecked in 3-6 months.

Drugs that increase rhabdomyolysis risk when used concurrently include fibrates, red yeast rice, niacin, daptomycin. Monitor these patients closely for symptoms of muscle pain. Can also monitor CPK and decrease the dose of the statin in these patients. 3A4 interactions can increase the concentration of statins. These include clarithromycin, grapefruit juice, amiodarone, amantadine, and verapamil. 3A4 inducers can decrease the concentration of statins. These include St. John’s Wort and carbamazepine. 

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Simvastatin Pharmacology

Simvastatin use has declined over time due to more potent statins being available and due to numerous drug interactions.

Grapefruit juice can inhibit CYP3A4 which will increase the concentrations of simvastatin.

Genetic variations in SLCO1B1 can lead to patients being more susceptible to simvastatin toxicity.

Simvastatin is a lipophilic statin. I discuss why this is important and how it might impact clinical decisions.

I discuss important drug interactions on the podcast, be sure to check out my latest project which is a 200+ page book on managing drug interactions in primary care.

Be sure to check out our free Top 200 study guide – a 31 page PDF that is yours for FREE!

Colestipol Pharmacology

Colestipol is a bile acid sequestrant that can be used in the management of hyperlipidemia.

By binding bile acid in the gut, colestipol can lower LDL that is bound to bile acid by eliminating it through the feces.

Numerous drug interactions existed as colestipol can bind many drugs. This is a downside to its use and why it isn’t a preferred hyperlipidemia agent.

In patients with elevated triglycerides, colestipol should be avoided.

I discuss important drug interactions on the podcast, be sure to check out my latest project which is a 200+ page book on managing drug interactions in primary care.

Ezetimibe Pharmacology

Ezetimibe Pharmacology

On this episode, I discuss ezetimibe pharmacology. Ezetimibe works by inhibiting Niemann-Pick C1-Like1 (NPC1L1) transporter. This transporter aids in cholesterol absorption so by blocking it, we can reduce cholesterol levels (and LDL) in the bloodstream.

Ezetimibe is usually very well tolerated. Diarrhea, myopathy, and elevations in LFT’s are adverse effects that have been reported but do not occur at high rates.

Ezetimibe is dosed at 10 mg once daily. This is a nice advantage because this is a starting dose and the usual treatment dose.

With the most recent cholesterol guideline updates, I do expect ezetimibe to be utilized a little more than it used to be. They place more emphasis on a target LDL and getting patients to goal.

Statins are going to be used first line for cholesterol and ezetimibe will be an add on therapy to consider. They don’t, unfortunately, lower cholesterol as much as high-intensity statins do.

Be sure to check out our free Top 200 study guide – a 31 page PDF that is yours for FREE!