Pharmacologic: calcium channel blockers (dihydropyridine)
Reduction of blood pressure when oral therapy is not feasible/desirable.
Inhibits calcium transport into vascular smooth muscle, resulting in inhibition of excitation-contraction coupling and subsequent contraction. Decreases systemic vascular resistance; does not reduce cardiac filling pressure (preload). Has no effect on venous capacitance vessels. Therapeutic Effects: Decreases blood pressure.
Adverse Reactions/Side Effects
CNS: headache. CV: CHF, hypotension, rebound hypertension, reflex tachycardia. GI: nausea, vomiting. MS: arthralgia.
PHYSICAL THERAPY IMPLICATIONS
Examination and Evaluation
Assess blood pressure periodically and compare to normal values (See Appendix F) to help document antihypertensive effects.
Assess signs of congestive heart failure, including dyspnea, rales/crackles, peripheral edema, jugular venous distention, and exercise intolerance. Report these signs to the physician immediately.
Assess heart rate and ECG during and after IV administration (See Appendices G, H). Report an increase in heart rate, especially if BP decreases substantially (reflex tachycardia).
Assess any joint pain to rule out musculoskeletal pathology; that is, try to determine if pain is drug induced rather than caused by anatomic or biomechanical problems.
Because of an increased risk of hypotension and reflex tachycardia, use caution during aerobic exercise and endurance conditioning. Terminate exercise if patient exhibits untoward symptoms (chest pain, shortness of breath, excessive fatigue) or displays other criteria for exercise termination (See Appendix L).
Avoid physical therapy interventions that cause systemic vasodilation (large whirlpool, Hubbard tank). Additive effects of this drug and the intervention may cause a dangerous fall in blood pressure.
To minimize orthostatic hypotension, patient should move slowly when assuming a more upright position.
Counsel patients about additional interventions to help control blood pressure, including regular exercise, weight loss, sodium restriction, stress reduction, moderation of alcohol consumption, and smoking cessation.
Instruct patient or family/caregivers to report other troublesome side effects such as severe or prolonged headache or GI problems (nausea, vomiting).
Absorption: IV administration results in complete bioavailability.
Metabolism and Excretion: Rapidly metabolized by esterases in plasma and tissue to inactive metabolites; metabolites are excreted in urine (63–74%) and feces (7–22%).
Half-life: Initial phase—1 min; terminal phase—15 min.
Contraindicated in: Hypersensitivity; Allergy to soybeans, eggs/egg products, ...