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Ask the Pharmacist
by Ron & Marla Chapleau

February 13, 2017
www.saugeentimes.com
www.kincardinetimes.com

Health

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Q) My father fell the other day pretty much as soon as he stood up. His doctor told him he has orthostatic hypotension. What does that mean and what can we do about it?

A) Orthostatic hypotension (OH) is a chronic, sometimes debilitating illness that is common (up to 20% of those over age 65 have drops in blood pressure upon standing) in the elderly and often difficult to treat. It is entirely related to blood pressure so a quick reminder of some of the more common terms is probably in order.

 Blood pressure is written as two numbers, for example 130 over 80 and is measured in units known as millimetres of mercury (mmHg).

The first number is the systolic pressure. This is the pressure in your arteries when they are maximally expanded due to the fact that the heart has pumped a mass of blood into them. The diastolic is the second number and this is taken when the arteries are relaxed in between heart beats.

Orthostatic hypotension (OH) is defined as a rather sudden (within 3 minutes of standing up) and dramatic drop in either the systolic (greater than 19mmHg) or the diastolic blood pressure (greater than 9 mmHg).

The physiological explanation of what occurs is as follows; When we stand up, gravity pulls the blood down from the chest into the many blood vessels that reside below our diaphragm in our abdomen. This shift of blood causes our heart to suddenly receive less blood (since some of it is now in our abdomen) and therefore to pump out less blood which leads to a natural decrease in our blood pressure (the less blood going through an artery, the less force against its walls).

This process occurs in everyone, but in most of us (i.e. those of us without OH) there is a mechanism that compensates for this instantly and maintains our blood pressure at roughly the same value. This mechanism is termed a baroreflex and what happens in this instance is that sensors in our cardiovascular system detect the change and signal the heart to beat faster and our blood vessels to narrow (constrict) all of which serve to keep the blood pressure relatively stable.

In those with OH, one of three things has gone wrong. It could be that this baroreflex reflex is no longer functioning properly (it is run by our nervous system), some of our organs (notably the heart and kidneys) are damaged or we simply do not have enough blood (known as volume depletion) to ratchet the blood pressure back up.

These 3 possible failures serves to explain just who is more likely to suffer from OH. People at risk include the elderly; those with various heart conditions; other diseases that affect our endocrine system (diabetes, thyroid disorders, adrenal insufficiency); a wide assortment of medications (including but not limited to diuretics, alpha- blockers - which are used for enlarged prostates, the tricyclic antidepressants -which are commonly used for nerve pain, migraine prevention and insomnia, drugs for erectile dysfunction , drugs for high blood pressure, muscle relaxants, narcotics, antipsychotics - which are also frequently used to aid in treating depression and sometimes for sleep, and some of the drugs used to treat Parkinsonís); those who are volume depleted (possibly due to dehydration, elevated sugar, bleeding, diarrhea or vomiting..); pregnancy; the immobile; the anemic; those exposed to hot weather; and patients diagnosed with Parkinsonís.

The symptoms of OH vary but can include a feeling of dizziness or light-headedness upon standing (the hallmark symptom of this disorder), blurred vision, nausea, disorientation or confusion, feeling of weakness, fatigue, falling or chest pain.

Management, as was mentioned earlier can be challenging. The first step is to root out the cause. If itís deemed to be related to a medication, then possibly lowering the dose or changing to another pharmaceutical option may alleviate the situation. Before lowering the dose of an antihypertensive, however, the patientís regular blood pressure should be noted since an uncontrolled blood pressure can also worsen the symptoms of OH.

The family of BP drugs known as the calcium channel blockers (amlodipine, diltiazem...) are less likely to contribute to OH and may be an alternative for some. Taking certain drugs (such as the Parkinsonís ones) with one or two glasses of water can help counteract the drop in BP as well.

The case for compression stockings is convoluted, as the evidence to support the knee or thigh high ones is limited at best. The ones that come right up and compress both the leg and abdominal vessels appear to be effective but are difficult to put on and use for many. Instead, an abdominal binder can be worn and if additional compression is needed the normal compression leg stockings can be added.

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There are many lifestyle measures that can significantly improve symptoms as well. These include maintaining an adequate fluid intake (e.g. 1.25-2.5 litres per day); adding 2 cups of caffeinated coffee to your meals can help prevent post-meal dips in BP which are very commonly a problem period for people with OH; avoiding large meals and instead consuming smaller more frequent and preferably low- carbohydrate options; limiting alcohol intake; avoiding sitting up or standing too quickly; minimizing exposure to hot temperatures (including baths and showers); exercising regularly; elevating the head of the bed by about 4 inches; adding salt to your diet (1/2 -1 teaspoonfuls) three times a day; contracting muscles for 30 seconds then relaxing and repeating (such as contracting buttocks, thighs and calves while standing); and drinking 2 eight ounce glasses of cold water quickly back to back just prior to situations that are known to typically cause symptoms.

Obviously, some of these measures are not appropriate for certain individuals so when in doubt, consult the appropriate health professional.

Lastly there are drugs that can be used. Fludrocortisone is considered a first line option in patients without electrolyte abnormalities, hypertension or heart failure. It increases the sodium within your body which in turn leads to an increase in the retention of water (see your kidís grade 7 notes on osmosis, or donít....). It has a long duration of action so that one dose a day can provide all day benefit. The dose should be started low (say 0.1mg) and increased slowly on a weekly basis if needed while blood pressure, edema (excessive fluid retention) and potassium levels should be monitored.

If patients can tolerate the increased volume that fludrocortisone involves then midodrine can be initiated. It has a relatively short duration of action as it elevates blood pressure for only 2-3 hours at a time. As such, it needs to be dosed three times a day and can be increased weekly much like fludrocortisone. It can also be used on a ďjust when neededĒ type basis as well. For instance, it can be 30-45 minutes prior to upright activities for those who do not want to take the drug on a regular basis. Adverse effects include goose bumps, paresthesia (a burning or tingling sensation usually felt in the extremities), urinary retention and supine hypertension.

Other drug options that can be explored include clonidine, hydralazine, a nitroglycerin patch, nifedipine, losartan and a host of others with limited data supporting their effectiveness.

OH can be a major nuisance to those who suffer from it, but there is hope to be gleaned from all the measures that can be used to counteract it.

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For more information about this or any other health related questions, contact the pharmacists at Gordon Pharmasave, Your Health and Wellness Destination in Port Elgin and Kincardine.



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