Hypertension drugs used

Anti hypertensives drugs used for high blood pressure. 

Additive sympathomimetic effects may develop when decongestants are administered with other sympathomimetic drug s (see Chap. 22). Use of the nasal decongestants with the MAOIs may cause hypertensive crisis. Use of a decongestant with beta-adrenergic blocking dragp may cause hypertension or bradycardia. When ephedrine is administered with theophylline, the patient is at increased risk for theophylline toxicity. 

Vasodilating drags sometimes relieve die symptoms of vascular disease, but in some cases dragtherapy provides only minimal and temporary relief. Many of die vasodilating drug s are also used to treat hypertension. Their use as antihypertensives is discussed in Chapter 42. 

List the various types of drugs used to treat hypertension. 

Discuss ways to promote an optimal response to therapy, how to manage adverse reactions, and important points to keep in mind when educating patients about the use of an anti hypertensive drug. 

Epoetin alfa (erythropoietin EPO) and darbepoetin alfa are usually well tolerated. The most common adverse reactions include hypertension, headache, tachycardia, nausea, vomiting, diarrhea, skin rashes, fever, myalgia, and skin reaction at tlie injection site. See the Summary Drug Table Drug Used in the Treatment of Anemia for more information on these drug. 

McTavish, D., Sorkin E. M., Verapamil an updated review of its pharmacodynamic and pharmacokinetic properties, and therapeutic use in hypertension, Drugs 1989, 38, 19-76. 

Finally be aware of the fact that more and more drugs are used by the elderly that can have negative effects on the kidney function. Anti-hypertensive drugs are often needed to reach lower blood pressure levels in the elderly but this can... 

Drugs used in the treatment of hypertension vary greatly in their mode of interference with sympathetic nerve function. In the case of methyldopa the mechanism is complex and still largely unknown. Others, such as guanoxan, guanochlororbethanidine, involve varying degrees of, for example catecholamine depletion, blockade of subsequent release of noradrenaline and, occasionally, a weak receptor-blockade. Bethanidine is perhaps the best-known of this series and... 

Prazosin is used for treating mid-to-moderate hypertension. When using this drug, blood pressure is reduced without any significant change in indicators of cardiac function such as frequency, coronary flow, or cardiac output. Synonyms of this drug are minipress and minizide. 

Clonidine is a selective Oj-adrenergic agonist that exhibits pronounced hypotensive action that is associated with a reduction of overall peripheral vascular resistance, decline in frequency of cardiac contraction, and reduced cardiac output. Clonidine is the drug of choice for treating various degrees of hypertension when used in combination with oral diuretics. 

Sodium nitroprusside is a powerful, instantaneous-acting intravenous drug used to lower blood pressure in hypertensive crises. The hypotensive effect is caused by peripheral vasodilation resulting from a direct effect on both arterial and venous vessels. 

Moreover, whether or not hypertension is caused by an elevated level of renin or other reasons, angiotensin-converting enzyme inhibitors lower both systolic and diastolic arterial pressure in hypertensive patients, and their effects are enhanced by diuretics. Angiotensin-converting drugs of this series (captopril, enalapril) are effective antihypertensive drugs used both independently and in combination with other drugs to treat all types of hypertension as well as to treat cardiac insufficiency. 

Many of the drugs used in the treatment of hypertension and cardiovascular disease are designed to interfere with the action of cell-surface receptors that couple to heterotrimeric G proteins. 

A related problem of poor prescribing is the undertreatment of treatable disease. This is an area in which some direct-to-consumer advertising could turn out to be a good thing. Examples of diseases that are undertreated include depression, hypertension and incontinence. Here too, a better flow of information to doctors could make a big difference in improving appropriate drug use. 

Since the main clinical use for antisympathotonics is in the treatment of essential hypertension, such drugs will be discussed in Chapter 20 in more detail. The alkaloid reserpine from Rauwolfia serpentina was the first drug used clinically to reduce sympathetic tone. Reserpine reduce the ability of storage and release of various transmitters (adrenaline, noradrenaline, serotonine and dopamine) by an irreversible destruction of the axonal vesicle membranes. The duration of the reserpine effect is actually determined by the de novo synthesis of these structure. Beside various central side effects like sedation, depression, lassitude and nightmares the pattern of unwanted effects of reserpine is determined by the shift of the autonomic balance towards the parasympathetic branch myosis, congested nostrils, an altered saliva production, increased gastric acid production, bardycardia and diarrhea. As a consequence of the inhibition of central dopamine release, reserpine infrequently shows Parkinson-like disturbances of the extrapyramidal system. 

Fig. 7. Sites of action of the major classes of diuretic drugs used in fluid retention states and in hypertension.

Clinically, diuretics are among the most widely prescribed drugs used in the management of hypertension and various edematous states like congestive heart failure, nephrotic edema and in some cases of edema in pregnancy. 

Finally, one should note that all of the agents that lower blood pressure by altering sympathetic function can elicit compensatory effects through mechanisms that are not dependent on adrenergic nerves. Thus, the antihypertensive effect of any of these agents used alone may be limited by retention of sodium by the kidney and expansion of blood volume. For this reason, sympathoplegic anti hypertensive drugs are most effective when used concomitantly with a diuretic. 

---