An antihypertensive drug is any agent that reduces blood pressure. There are many different classes and they are used in slightly situations. They are prescribed for hypertension and hope to prevent side effects such TIAs, Strokes and Myocardial Infarction. Classes of antihypertensive drugs include diuretics calcium channel blockers, ACE inhibitors, angiotensin II receptor antagonists, adrenergic antagonists, Benzodiazepines, Renin inhibitors and aldosterone receptor antagonists.
Examples and Uses of Antihypertensive Drugs
Thiazide diuretics are used to treat hypertension and edema. They work by inhibiting the sodium chloride symporter. It increases in fluid loss, decreases blood volume and reduced blood pressure.
ACE inhibitors are also used to treat hypertension but act by inhibiting angiotensin converting enzyme. This reduces activity of the renin angiotensin aldosterone system and thus reduces blood pressure. Examples include ramipril.
Antihypertensive Drugs side effects
Thiazide diuretics like bendroflumethiazide cause a number of side effects. These include:
- Syncope (fainting)
- Hypotension (low blood pressure_
- Gastric irritation
- Abdominal pain
ACE inhibitors are also associated with a number of side effects. These include:
- Angina pectoris (chest pain)
- Postural hypotension
- Abdominal discomfort
- Syncope (fainting)
- Muscle spasm
- Myalgia (muscle pain)
Most patients do not suffer adverse reactions when taking antihypertensives. However some patients may suffer from many side effects. This inter patient variability is in part accounted for by pharmacogenetics. Polymorphisms in the enzymes and receptors that interact with antihypertensives can increase the probability of patients developing side effects.
Most antihypertensives are metabolized by the cytochrome P450 superfamily of enzymes (the specific isoenzymes will vary on class and drug). Polymorphisms in these enzymes have been shown to increase the probability of developing side effects. Identifying these alleles can aid clinicians in prescribing antihypertensives and could reduce the risk of developing adverse reactions. MD Labs’ Rxight® sequences a number of genes and their alleles to establish how patients are likely to respond to hundreds of medications (including most antihypertensives).
Antihypertensive Interactions and Contraindications
ACE inhibitors like ramipril interact with a number of drugs including, other diuretics, agents that increase potassium, Lithium, Gold, NSAID and mTOR inhibitors. Its use is contraindicated in patients with diabetes (when patient is on Aliskiren).
Thiazide diuretics interact with Alcohol, other antihypertensives, antidiabetic drugs, corticosteroids, Lithium and NSAIDs. Its use is contraindicated in patients who have known hypersensitivity to sulfonamide derivatives.