Prescription medication · Short-Acting Insulin

insulin regular

Also sold as Humulin R, Novolin R. Humulin R is used to improve blood sugar control in adults and children with diabetes.

Data updated 2026-05-15

11
InteractionsSeveral interactions
$4.27
Brand price (NADAC)

insulin regular (Humulin R) is a prescription Short-Acting Insulin. Humulin R is used to improve blood sugar control in adults and children with diabetes.

Humulin R is a short-acting insulin that helps control blood sugar levels in people with diabetes. It works quickly to lower blood sugar after meals.

Drug Pricing (NADAC)

Brand Price

$4.27/unit

Generic Available

No

Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →

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What it does

Humulin R is used to improve blood sugar control in adults and children with diabetes.

Common side effects

Low blood sugar (hypoglycemia), Reactions at the injection site (redness, swelling, itching), Skin thickening or pits at the injection site

Key warnings

Never share needles or syringes with anyone else, even if they are family.

The sections below are summarized in plain English from insulin regular's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.

How It Works

Humulin R is a type of insulin that replaces the insulin your body is not making. It helps sugar move from your blood into your cells, which lowers your blood sugar levels. This insulin starts working quickly and does not last very long.

Serious Warnings

Never share needles or syringes with anyone else, even if they are family. Sharing needles can spread blood-borne illnesses. Changes in your insulin dose should be made carefully under your doctor's supervision, as this can cause high or low blood sugar. Low blood sugar can be very dangerous and even life-threatening. If you have heart failure, talk to your doctor before using Humulin R, as it can worsen this condition.

Known Drug Interactions

moderate fluoxetine

7 DRUG INTERACTIONS Table 1: Clinically Significant Drug Interactions with HUMULIN R Drugs that May Increase the Risk of Hypoglycemia Drugs: Antidiabetic agents, ACE inhibitors, angiotensin II receptor blocking agents, disopyramide, fibrates, fluoxetine, monoamine oxidase inhibitors, pentoxifylline, pramlintide, salicylates, somatostatin analog (e.g., octreotide), and sulfonamide antibiotics Intervention: Dose adjustment and increased frequency of glucose monitoring may be required when HUMULIN R is co-administered with these drugs.

Mechanism: Fluoxetine can increase the blood-sugar-lowering effect of insulin, which may cause your blood sugar to drop to an unsafe level.

moderate pramlintide

7 DRUG INTERACTIONS Table 1: Clinically Significant Drug Interactions with HUMULIN R Drugs that May Increase the Risk of Hypoglycemia Drugs: Antidiabetic agents, ACE inhibitors, angiotensin II receptor blocking agents, disopyramide, fibrates, fluoxetine, monoamine oxidase inhibitors, pentoxifylline, pramlintide, salicylates, somatostatin analog (e.g., octreotide), and sulfonamide antibiotics Intervention: Dose adjustment and increased frequency of glucose monitoring may be required when HUMULIN R is co-administered with these drugs.

Mechanism: Pramlintide increases the risk of low blood sugar when used with insulin because both drugs work to lower glucose levels.

moderate octreotide

7 DRUG INTERACTIONS Table 1: Clinically Significant Drug Interactions with HUMULIN R Drugs that May Increase the Risk of Hypoglycemia Drugs: Antidiabetic agents, ACE inhibitors, angiotensin II receptor blocking agents, disopyramide, fibrates, fluoxetine, monoamine oxidase inhibitors, pentoxifylline, pramlintide, salicylates, somatostatin analog (e.g., octreotide), and sulfonamide antibiotics Intervention: Dose adjustment and increased frequency of glucose monitoring may be required when HUMULIN R is co-administered with these drugs.

Mechanism: Octreotide can lower blood sugar levels, which adds to the effect of insulin and increases the risk of a dangerous drop.

Drugs that May Decrease the Blood Glucose Lowering Effect of HUMULIN R Drugs: Atypical antipsychotics (e.g., olanzapine and clozapine), corticosteroids, danazol, diuretics, estrogens, glucagon, isoniazid, niacin, oral contraceptives, phenothiazines, progestogens (e.g., in oral contraceptives), protease inhibitors, somatropin, sympathomimetic agents (e.g., albuterol, epinephrine, terbutaline), and thyroid hormones.

Mechanism: Albuterol can cause the body to produce more sugar or make it harder for insulin to lower it. This means your blood sugar might not drop as much as it usually does with insulin.

Drugs that May Increase or Decrease the Blood Glucose Lowering Effect of HUMULIN R Drugs: Alcohol, beta-blockers, clonidine, and lithium salts. Drugs that May Blunt Signs and Symptoms of Hypoglycemia Drugs: Beta-blockers, clonidine, guanethidine, and reserpine Intervention: Increased frequency of glucose monitoring may be required when HUMULIN R is co-administered with these drugs. ( 7 ) Antiadrenergic Drugs (e.g., beta-blockers, clonidine, guanethidine, and reserpine): Signs and symptoms of hypoglycemia may be reduced or absent.

Mechanism: This drug can change how your body responds to insulin and may also hide the warning signs of low blood sugar, like a fast heartbeat. This makes it harder to tell if your blood sugar has dropped too low.

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This is a plain-language summary of FDA-label interaction records and does not provide individual medication-combination directions.

Common Questions

What should Humulin R look like?
Humulin R should be clear and colorless. Do not use it if it is cloudy or has particles in it.
Can I mix Humulin R with other insulins?
You can mix Humulin R with Humulin N.
What if my blood sugar is too low?
If your blood sugar is low, eat or drink something with sugar in it, like juice or hard candy. Check your blood sugar again after 15 minutes. Contact your doctor if you have frequent low blood sugar.
What if my blood sugar is too high?
If your blood sugar is high, follow your doctor's instructions for adjusting your insulin dose or taking other steps to lower it. Contact your doctor if you have frequent high blood sugar.
Can other medicines affect Humulin R?
Yes, many medicines can affect your blood sugar levels. Tell your doctor about all the medicines you take, including over-the-counter drugs and supplements.
What are the symptoms of low blood sugar?
Symptoms of low blood sugar can include sweating, shaking, dizziness, hunger, confusion, and blurred vision.
What are the symptoms of high blood sugar?
Symptoms of high blood sugar can include increased thirst, frequent urination, blurred vision, and fatigue.
Can I travel with Humulin R?
Yes, but be sure to keep it with you and protect it from extreme temperatures. Bring extra insulin and supplies in case of delays.
What should I do if I have an allergic reaction to Humulin R?
Stop using Humulin R and get medical help right away if you have signs of an allergic reaction, such as rash, itching, swelling, or trouble breathing.
Who should not take Humulin R?
You should not take Humulin R if you are having an episode of low blood sugar or if you are allergic to it or any of its ingredients.
What are the common side effects of insulin regular?
The registry lists Low blood sugar (hypoglycemia), Reactions at the injection site (redness, swelling, itching), Skin thickening or pits at the injection site, Weight gain, Swelling in your arms and legs among the most-reported FAERS reaction terms for insulin regular. These counts are not an individual symptom assessment.
Does insulin regular interact with other medications?
The registry has 11 documented interaction rows for insulin regular. Notable source-record pairings include fluoxetine, pramlintide, octreotide. These rows are not a complete medication review.
What drug class is insulin regular?
insulin regular belongs to the Short-Acting Insulin drug class. It requires a prescription (Rx). Humulin R is used to improve blood sugar control in adults and children with diabetes.
What pregnancy or breastfeeding source fields are listed for insulin regular?
The FDA label for insulin regular contains product-specific pregnancy or breastfeeding language. PlainMeds does not apply that source text to an individual.

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What the FDA Data Shows for insulin regular

The FDA label for insulin regular (sold under brand names such as Humulin R, Novolin R) classifies it as a prescription-only medication in the Short-Acting Insulin class. Humulin R is used to improve blood sugar control in adults and children with diabetes. Official labeling lists 7 commonly reported side effects, including Low blood sugar (hypoglycemia), Reactions at the injection site (redness, swelling, itching), Skin thickening or pits at the injection site.

Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. Voluntary reports accumulate over the lifetime of a drug and reflect wide-ranging clinical use. The database also lists 11 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated moderate severity. NADAC pricing from CMS.

Report counts do not establish causation, a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information are separate source-record fields. This page is a public FDA/CMS registry and does not provide medical, treatment, substitution, or medication-change directions.

Data Sources

Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).

FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. This registry does not provide medication decisions.

Last updated: October 31, 2023

PlainMeds is rendered directly from FDA openFDA/FAERS extracts, DailyMed labels, and CMS drug-pricing files, no number is typed in by an editor. FAERS counts, recalls, shortages, and price figures on this page are queried live from those federal extracts. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2026-05-15. Primary sources: openFDA / FAERS, DailyMed and CMS Part B ASP.

Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled from the source snapshot dated . See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a data issue.

All federal data sources used on this page