Are there particular concerns for older adults?
Older adults should have periodic magnesium blood levels taken if they use supplemental magnesium. Even a mild and otherwise not apparent degree of kidney dysfunction, which is often seen in this age group, may lead to toxic levels of magnesium with modest doses.
Recent studies have indicated that vitamin D (a vitamin required for the normal absorption of calcium from food) deficiency is common in some elderly individuals. Consequently, vitamin D replacement is important for these people, taking appropriate care to avoid excessive vitamin D levels, as these are toxic. An intake at least 400 units daily has been recommended in the past; more recently, experts have questioned whether this dose of vitamin D is sufficient, especially for people with little or no sun exposure (sunlight promotes the formation of vitamin D in the body). However, excessive doses of vitamin D are known to be toxic. The upper limit of dosing for vitamin D supplementation has been recommended as 2,000 IU daily. Your health care professional can help you decide how much vitamin D you should take, taking your individual situation and medical history into account.
While the more potent diuretics are associated with an increased loss of calcium and magnesium, hydrochlorothiazide (HydroDIURIL and others) and related diuretics are associated with calcium and magnesium retention. Diuretics are commonly used for the treatment of hypertension and heart failure. If cramps (or osteoporosis) are also a problem, the patient and doctor may consider using hydrochlorothiazide or another thiazide type of diuretic if otherwise feasible and appropriate.
Diuretics also cause sodium depletion and most also cause potassium depletion. Many patients who use diuretics are also on sodium-restricted diets. Careful attention to the effects of diuretics on sodium and potassium, and replacement of these elements as needed, is always appropriate, even more so if cramps are a problem.
Older adults often do not hydrate themselves adequately, partly because the sense of thirst diminishes with age. This situation is exaggerated in those who are treated with diuretics. For some, simply increasing fluid intake to the generally recommended six to eight glasses a day will improve the cramps. However, drinks with caffeine should not be counted since they act on the kidneys to increase fluid loss. Individuals who are on restricted fluid intake should consult their doctor on this issue and must not ignore their recommended fluid intake limits.
As for night cramps, the exact cause is often difficult to determine. The best prevention involves stretching regularly, adequate fluid intake, appropriate calcium and vitamin D intake, supplemental vitamin E, and possibly -- with physician consultation -- supplemental magnesium intake.