How much do you know about cardiovascular drugs? Common side effects of antihypertensive drugs

Date:2020-02-17

Principles of and types of drugs used for cardiovascular disease

There are many types of cardiovascular drugs, and their drug usage principles are quite different. These drugs also possess the function of preventing the formation of blood clots. Anticoagulants commonly known as blood-thinning pills or blood thinners (such as Warfarin) help prevent blood clots from forming in blood vessels by preventing the body from producing clotting factors; antiplatelets drugs (for example Clopidogrel) prevent the body from producing thromboxane and are also suitable for preventing heart attacks and strokes.

However, even if they belong to the same drug usage category, doctors may prescribe different drugs for you depending on individual patient differences. As examples, Atorvastatin and Simvastatin are commonly used drugs in the reduction of cholesterol and heart disease risk. They all block HMG-CoA reductase to reduce the liver's production of cholesterol, but the recommended dosage and side effects of the two are different.

Principles of and types of drugs used for cardiovascular disease

Common side effects of antihypertensive drugs

Hypertension is one of the most common urban diseases. Hypertension increases the risk of myocardial infarction and stroke, so medication is a common method of blood pressure regulation and symptom suppression. As such, it is important to be aware of the potential medications which mitigate CVD, as well as their side effects. As antihypertensive drugs are so widely used, it is crucial to note their different effects, including adverse ones.

Drug types Drug names Side effect
Alpha Blocker Doxazosin, Prazosin Drowsiness; orthostatic hypotension; dizziness
Angiotensin-converting enzyme (ACE) inhibitors Enalapril, Lisinopril, Perindopril Persistent dry cough; headache; dizziness; facial edema; tongue swelling
Angiotensin II receptor blockers Losartan Headache; dizziness
Beta Blocker Carvedilol, Metoprolol Tiredness; cold hands and feet; slowed heartbeat; gastrointestinal discomfort; insomnia; changes in male sexual performance
Calcium channel blockers (CCB) Diltiazem, Nifedipine, Amlodipine Facial flushing; headache; ankle swelling; constipation; edema of limbs
Diuretics Amiloride, Furosemide, Indapamide hemihydrate Frequent urination; dizziness; gastrointestinal discomfort

What factors affect drug response?

In addition to the expected effects after taking the drug, there may be unwanted side effects, including toxic reactions or allergic reactions. Everyone has the chance to respond differently to the same type and dose of drugs, which are affected by external or internal factors. An example of an external factor is when the patient is taking other drugs at the same time, where drug interaction may occur. Additionally, further drug reactions may occur depending on the type of food and drink consumed. Internal, personal factors which may affect response to drug intake include height, weight, age, other diseases that affect physical function (such as kidney disease and liver disease), and even genetic differences.

Genetic differences in particular affect the metabolism of individuals; those with fast metabolisms quickly metabolize the drug, leading to the amount of the drug being not enough to exert its desired effect. Conversely, those with slow metabolisms struggle to internally metabolize the drugs, which will cause toxins to accumulate in the body, leading to side effects or adverse reactions.

As each person will have a varied response to medication, it is thus pivotal for an individual to acquire a personalized drug prescription appropriate for themselves, taking into account their genetic makeup and other personal factors.

Reduce the side effects of drugs with pharmacogenetics

From the "symptomatic", one-size-fits-all prescription of traditional medicine to the "symptom and gene" prescription of precision medicine, personalized medication is a major medical trend in recent years. Under traditional medical treatment, patients need to go through constant testing, drug changes, and dosage adjustments to reduce side effects or ineffective medication. They are all formulated by doctors or pharmacists based on experience, and the efficiency is low. Under precision medicine and through pharmacogenetics, we understand that individual genetic differences can lead to different drug reactions. We can directly rule out treatment options that are not suitable for patients, and recommend the most effective drug type and dosage for each patient to the doctor or pharmacist.

Case Analysis of Cardiovascular Medicine

An example of the drawbacks of the impersonalized prescription of cardiovascular medicine is simvastatin. Simvastatin is a drug commonly used to lower blood lipids and prevent cardiovascular disease, with common side effects including constipation, headache, and nausea. Some patients may, however, also develop serious side effects such as muscle disease; there have been patients who took simvastatin and subsequently acquired rhabdomyolysis. After drug genetic testing, it was found that patients with the SLCO1B1 gene mutation are correlated with adverse drug reactions to simvastatin – it is hence advised for such individuals to take a lower dose or switch their medication.

CoGenesis®心血管藥物基因檢測樣本報告
(Image: CoGenesis® Cardio-Haema drug response testing sample report)

Medication Instructions

Ultimately, drug responses are very complex and can be influenced by many factors, including genetics. After obtaining a drug genetic test report, you must find feasible medication plans under the guidance of a doctor or pharmacist. Please do not adjust the drug dosage or stop the drug yourself.