INSULIN, ISOPHANE (NPH)

Availability

100 units/mL

Action

Intermediate-acting, cloudy suspension of zinc insulin crystals modified by protamine in a neutral buffer. NPH Iletin II (pork), and Insulatard NPH are "purified" or "single component" insulins that have been purified and are less likely to cause allergic reactions than nonpurified preparations. Lowers blood glucose levels by increasing peripheral glucose uptake, especially by skeletal muscle and fat tissue, and by inhibiting the liver from changing glycogen to glucose.

Therapeutic Effect

Controls postprandial hyperglycemia, usually without supplemental doses of insulin injection.

Uses

Used to control hyperglycemia in the diabetic patient. Mixtard and Novolin 70/30 are fixed combinations of purified regular insulin 30% and NPH 70%.

Contraindications

During episodes of hypoglycemia or in patients sensitive to any ingredient in the formulation; intravenous route; diabetic ketoacidosis; hyperosmolar hyperglycemic state.

Cautious Use

In insulin-resistant patients, hyperthyroidism or hypothyroidism; fever; older adults, pregnancy (category B), renal or hepatic impairment; children.

Route & Dosage

Administration

• Give isophane insulin 30 min before first meal of the day. If necessary, a second smaller dose may be prescribed 30 min before supper or at bedtime.
• Ensure complete dispersion by mixing thoroughly by gently rotating vial between palms and inverting it end to end several times. Do not shake.
• Do NOT mix insulins unless prescribed by physician. In general, when insulin injection (regular insulin) is to be combined, it is drawn first.
• Note: Isophane insulin may be mixed with insulin injection without altering either solution. Do NOT mix with Lente forms.
• Store unopened vial at 2°–8° C (36°–46° F). Avoid freezing and exposure to extremes in temperature or to direct sunlight.

Adverse Effects (≥1%)

Interactions

Pharmacokinetics

Nursing Implications

(see INSULIN, REGULAR)

Assessment & Drug Effects

• Suspect hypoglycemia if fatigue, weakness, sweating, tremor, or nervousness occur.

Patient & Family Education

• If insulin was given before breakfast, a hypoglycemic episode is most likely to occur between mid-afternoon and dinnertime, when insulin effect is peaking. Advise to eat a snack in mid-afternoon and to carry sugar or candy to treat a reaction. A snack at bedtime will prevent insulin reaction during the night.
• Learn the S&S of hypoglycemia and hyperglycemia (see Appendix F).

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug