nph insulin (isophane insulin suspension)

Absorption: Rapidly absorbed from SUBQ administration sites. Presence of protamine delays peak effect and prolongs action.

Distribution: Identical to endogenous insulin.

Metabolism/Excretion: Metabolized by liver, spleen, kidney, and muscle.

Half-Life: Unknown.

Time/Action Profile ⬆ ⬇

(hypoglycemic effect)

ROUTE	ONSET	PEAK	DURATION
NPH SUBQ	2–4 hr	4–10 hr	10–16 hr
70% NPH/30% regular insulin mixture	30 min	2–12 hr	24 hr

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypoglycemia;
Allergy or hypersensitivity to a particular type of insulin, preservatives, or other additives.

Use Cautiously in:

Stress or infection (may temporarily ↑ insulin requirements);
Renal impairment (may ↓ insulin requirements);
Hepatic impairment (may ↓ insulin requirements);
OB: Pregnancy may temporarily insulin requirements;
Lactation: Use while breastfeeding only if potential maternal benefit justifies potential risk to infant.

Adv. Reactions/Side Effects ⬆ ⬇

Endo: HYPOGLYCEMIA

F and E: hypokalemia

Local: cutaneous amyloidosis, erythema, lipodystrophy, pruritus, swelling

Misc: HYPERSENSITIVITY REACTIONS (INCLUDING ANAPHYLAXIS)

Interactions ⬆ ⬇

Drug-drug:

Beta blockers and clonidine may mask some of the signs and symptoms of hypoglycemia.
Corticosteroids, thyroid supplements, estrogens, isoniazid, niacin, phenothiazines, and rifampin may ↑ insulin requirements.
Alcohol, ACE inhibitors, MAO inhibitors, octreotide, oral hypoglycemic agents, and salicylates may ↓ insulin requirements.
Concurrent use with pioglitazone may ↑ risk of fluid retention and worsening HF

Drug-Natural Products:

Glucosamine may worsen blood glucose control.
Fenugreek, chromium, and coenzyme Q-10 may produce additive hypoglycemic effects.

Route/Dosage ⬆ ⬇

Dose depends on blood glucose, response, and many other factors
SC (Adults and Children ): 0.5–1 unit total insulin/kg/day. Adolescents during rapid growth: 0.8–1.2 units total insulin/kg/day.

Availability ⬆ ⬇

Solution for injection (vials and prefilled pens): 100 units/mL

Assessment ⬆ ⬇

Assess patient periodically for symptoms of hypoglycemia (anxiety; restlessness; tingling in hands, feet, lips, or tongue; chills; cold sweats; confusion; cool, pale skin; difficulty in concentration; drowsiness; nightmares or trouble sleeping; excessive hunger; headache; irritability; nausea; nervousness; tachycardia; tremor; weakness; unsteady gait) and hyperglycemia (confusion, drowsiness; flushed, dry skin; fruit-like breath odor; rapid, deep breathing, polyuria; loss of appetite; unusual thirst) during therapy.
Monitor body weight periodically. Changes in weight may necessitate changes in insulin dose.

Lab Test Considerations:

Monitor blood glucose every 6 hr during therapy, more frequently in changes to insulin regimen, ketoacidosis, and times of stress. A1C may be monitored every 3–6 mo to determine effectiveness.
- Monitor serum potassium in patients at risk for hypokalemia (those using potassium-lowering agents, those receiving IV insulin) periodically during therapy.

Toxicity and Overdose:

Overdose is manifested by symptoms of hypoglycemia. Mild hypoglycemia may be treated by ingestion of oral glucose. Severe hypoglycemia is a life-threatening emergency; treatment consists of IV glucose, glucagon, or epinephrine.

Implementation ⬆ ⬇

Medication errors involving insulins have resulted in serious patient harm and death. Clarify all ambiguous orders and do not accept orders using the abbreviation "u" for units, which can be misread as a zero or the numeral 4 and has resulted in tenfold overdoses. Insulins are available in different types and strengths. Check type, dose, and expiration date with another licensed nurse. Do not interchange insulins without consulting other health care professional.
Do not confuse Humulin with Humalog or Novolin. Do not confuse Novolin N with Novolog.
Use only insulin syringes to draw up dose. The unit markings on the insulin syringe must match the insulin’s units/mL. Special syringes for doses <50 units are available. Prior to withdrawing dose, rotate vial between palms to ensure uniform solution; do not shake.
- When mixing insulins, draw regular insulin or insulin lispro into syringe first to avoid contamination of regular insulin vial.
- Insulin should be stored in a cool place but does not need to be refrigerated. Once opened, store at room temperature. Follow manufacturer's instructions regarding storage of insulin and insulin pens before and after use.
- When transferring from once-daily NPH human insulin to insulin glargine, the dose usually remains unchanged. When transferring from twice-daily NPH human insulin to insulin glargine, the initial dose of insulin glargine is usually reduced by 20%.
- NPH insulin should not be used in the management of ketoacidosis.
SC: Administer NPH insulin within 30–60 min before a meal. Inject SUBQ in abdomen, thigh, upper arm, or buttocks. Rotate injection sites to reduce risk of lipodystrophy or localized cutaneous amyloidosis. Repeated insulin injections into areas of lipodystrophy or localized cutaneous amyloidosis may result in hyperglycemia; and a sudden change in the injection site (to an unaffected area) may result in hypoglycemia.

Patient/Family Teaching ⬆ ⬇

Instruct patient on proper technique for administration. Include type of insulin, equipment (syringe, cartridge pens, alcohol swabs), storage, and place to discard syringes. Discuss the importance of not changing brands of insulin or syringes, selection and rotation of injection sites, and compliance with therapeutic regimen. Caution patient that insulin pens should not be shared with others, even if clean needles are used.
Demonstrate technique for mixing insulins by drawing up regular insulin or insulin lispro first and rolling intermediate-acting insulin vial between palms to mix, rather than shaking (may cause inaccurate dose).
Caution patient not to share pen device with another person, even if needle is changed; may risk transmission of bloodborne pathogens.
Explain to patient that this medication controls hyperglycemia but does not cure diabetes. Therapy is long term.
Instruct patient in proper testing of serum glucose and ketones. These tests should be closely monitored during periods of stress or illness and health care professional notified of significant changes.
Emphasize the importance of compliance with nutritional guidelines and regular exercise as directed by health care professional.
Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult health care professional before taking other Rx, OTC, herbal products, or alcohol.
Advise patient to notify health care professional of medication regimen prior to treatment or surgery.
Advise patient to notify health care professional if nausea, vomiting, or fever develops, if unable to eat regular diet, or if blood glucose levels are not controlled.
Instruct patient on signs and symptoms of hypoglycemia and hyperglycemia and what to do if they occur.
Patients with diabetes mellitus should carry a source of sugar (candy, glucose gel) and identification describing their disease and treatment regimen at all times.
Rep: Advise females of reproductive potential to notify health care professional if pregnancy is planned or suspected, or if breastfeeding.
Emphasize the importance of regular follow-up, especially during first few wk of therapy.

section name header

Classifications ⬇

Indications ⬆ ⬇

Action ⬆ ⬇

Pharmacokinetics ⬆ ⬇