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Pharmacy and Medications

Tell me about S Amlodipine

08/08/2005

Question:

I am male aged 48 years with hypertension on Atenolol-100 and Amlodipine 10 and Losartan 100. I have been taking medicies since 2 years. I developed swelling on both the legs. Doctor asked me to switch over S Amlodipine which has pure S Isomer. The dose is reduced to half because S Amlodipine 2.5 is equal to Amlodipine 5 mg. I want to know as to whether S Amlodipine is better than Amlodipine and it does not have side effects like ankle swelling or flushing ? Is is advisable to take S Amlodipine Please guide me.

Answer:

Amlodipine is a calcium channel blocker used to treat high blood pressure. Amlodipine, currently marketed in the United States as Norvasc®. This medicine is a combination of equal parts of the R and S isomers. Such a combination is called a racemic mixture. The R and S forms of the drug have different, but very similar, chemical structures. These structures are like mirror images of one another. Both structures are recognized by the body, but they produce different effects..

The S form of amlodipine appears to be the component primarily responsible for dilation of blood vessels and lowering of blood pressure. Our information indicates that the S- isomer of amlodipine is marketed in India as Asomex®. The S form of amlodipine is not currently commercially available in the United States, but it is being studied in clinical trials. In one study, S-Amlodipine 2.5 mg was found to be equal in its effect and tolerability compared to racemic amlodipine 5 mg in the treatment of mild to moderate high blood pressure. However, another study found that racemic amlodipine may offer cardiovascular benefits over and above those seen with S-amlodipine alone. The question of whether the S isomer alone is truly better than the mixture of R and S isomers awaits further study.

Typical side effects associated with both racemic amlodipine and S-amlodipinee include fatigue or tiredness, dizziness or fainting, headache, flushing, or swelling of the legs or ankles. If you are concerned about side effects that may occur with S-amlodipine, talk to your doctor or a pharmacist who knows you.

This response was prepared by Lauren Barton,a PharmD candidate at the University of Cincinnati College of Pharmacy.

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Response by:

Robert James Goetz, PharmD, DABAT
Assistant Professor of Pharmacy Practice
College of Medicine
University of Cincinnati