How should I administer premixed insulin 70/30 (70% NPH, 30% regular) to a patient?

How to Administer Insulin 70/30

Administer insulin 70/30 subcutaneously twice daily—2/3 of the total daily dose before breakfast and 1/3 before dinner—after rolling the vial horizontally 10 times to achieve a uniformly cloudy suspension, never shaking it. 1, 2

Preparation of the Insulin

Visual Inspection and Mixing

• Roll the vial gently 10 times horizontally in your hands until the suspension appears uniformly white and cloudy; never shake the vial, as this causes bubbles and froth that lead to inaccurate dosing 2
• Inspect the vial before each use—insulin 70/30 should appear uniformly cloudy or milky; if you see clumping, frosting, granular precipitate, or solid particles on the vial wall, discard it 3, 2
• Ensure the tamper-resistant cap is intact on first use; if it has been removed or the insulin appears abnormal, do not use it 2

Storage Requirements

• Store unopened vials in the refrigerator, but insulin in current use may be kept at room temperature to reduce injection site irritation from cold insulin 3
• Avoid temperatures below 36°F or above 86°F (<2°C or >30°C) and excessive agitation to prevent loss of potency 3

Drawing Up the Dose

Syringe Preparation Technique

• Clean the rubber stopper with an alcohol swab after removing the cap 2
• Pull back the plunger to the number of units you will inject, then push the needle through the stopper and inject this air into the vial 2
• Turn the vial and syringe upside down and slowly pull the plunger back a few units beyond your correct dose 2
• Tap the syringe gently to raise air bubbles to the top, then push the plunger to your exact dose marking to expel the air back into the vial 2
• Verify you have the correct dose before removing the needle from the vial 2

Injection Technique

Site Selection and Administration

• Rotate injection sites as instructed by your healthcare provider to prevent lipodystrophy 3, 2
• If cleaning with alcohol, allow the site to dry completely before injecting 2
• Ask your physician whether to pinch the skin before needle insertion, as this varies by patient 2
• Insert the needle into the skin and press the plunger completely to deliver the insulin 2
• After injection, pull the needle straight out—a small drop of insulin at the needle tip is normal and does not affect your dose 2
• If bleeding occurs, apply light pressure with gauze or an alcohol wipe without rubbing 2

Dosing Schedule and Timing

Standard Twice-Daily Regimen

• Administer 2/3 of the total daily dose before breakfast and 1/3 before dinner to provide both basal and prandial coverage throughout the day 1
• Give the injection immediately before or within 15 minutes of starting the meal 4
• Maintain consistent meal timing when using premixed insulin, as the fixed ratio of NPH to regular insulin requires predictable carbohydrate intake to prevent hypoglycemia 5

When Converting from NPH Insulin

• Calculate the total daily dose of 70/30 as 80% of the current NPH total daily dose (not 1:1) to reduce hypoglycemia risk 1
• Divide this reduced dose as 2/3 before breakfast and 1/3 before dinner 1
• Monitor blood glucose more frequently during the transition period, checking both fasting and postprandial levels 1
• If the patient's HbA1c is <8% when switching, consider further dose reduction to avoid hypoglycemia 1

Monitoring and Titration

Glucose Targets

• Target fasting glucose between 80–130 mg/dL (4.4–7.2 mmol/L) as the primary titration goal 5
• Monitor both fasting and postprandial glucose levels, as 70/30 addresses both components 1, 5
• Watch closely for hypoglycemia during the transition period, especially at night 1

Safety Considerations and Disposal

Needle Safety

• Never recap needles after injection to prevent needlestick injuries 2
• Never reuse syringes or needles 2
• Dispose of used syringes, needles, and vials in a puncture-resistant sharps container or hard plastic/metal container with a screw-on cap 2
• Do not throw used needles in household trash or recycling 2

Critical Pitfalls to Avoid

Common Errors

• Never shake the vial—only roll it horizontally to mix, as shaking creates air bubbles that cause dosing errors 2
• Never use the same dose for morning and evening injections—the morning dose should be approximately twice the evening dose (2/3 vs 1/3 split) 1, 5
• Never convert from other insulin regimens on a 1:1 basis—reduce the total daily dose by 20% when switching to prevent hypoglycemia 1
• Never mix insulin 70/30 with any other insulin in the same syringe, as it is a premixed formulation 3
• Do not use 70/30 in hospitalized patients, as it carries unacceptably high hypoglycemia risk (64% vs 24% with basal-bolus regimens) without improving glycemic control 5

Patient Selection Errors

• Avoid 70/30 in patients with irregular meal timing or variable carbohydrate intake, as the fixed ratio lacks flexibility 5
• Do not use in patients requiring maximum dosing flexibility—basal-bolus regimens are superior in these cases 5