Endocrine drugs: diabetes, thyroid and steroids

Endocrine Drugs: Diabetes, Thyroid, and Steroids

The endocrine system uses hormones to regulate metabolism, blood sugar, growth, and stress responses. Pharmacy technicians encounter endocrine medications daily, so understanding drug categories, storage rules, and common products is essential.

Insulin: Types and Time Profiles

Insulin is a hormone produced by the pancreas that allows cells to use glucose. Patients with type 1 diabetes require insulin; many patients with type 2 diabetes also use it. Insulins are classified by how quickly they start working (onset), when they work hardest (peak), and how long they last (duration).

Rapid-acting insulins begin working within 15 minutes, peak in 1–2 hours, and last 3–5 hours. They are given just before or with meals. Common examples include insulin lispro (Humalog), insulin aspart (NovoLog), and insulin glulisine (Apidra).

Short-acting insulin (regular insulin, such as Humulin R or Novolin R) has an onset of 30–60 minutes, peaks at 2–4 hours, and lasts 5–8 hours. It is given 30 minutes before meals.

Intermediate-acting insulin (NPH, such as Humulin N or Novolin N) starts working in 1–2 hours, peaks at 4–12 hours, and lasts 12–18 hours. It is often combined with a short-acting insulin.

Long-acting insulins have no pronounced peak and provide a steady background (basal) level of insulin for up to 24 hours or longer. Examples include insulin glargine (Lantus, Basaglar) and insulin detemir (Levemir). Insulin degludec (Tresiba) can last beyond 42 hours.

Premixed insulins combine NPH with a rapid- or short-acting insulin in fixed ratios (for example, 70/30 products) for patients who need both basal and mealtime coverage in fewer injections.

Insulin Storage

Proper storage prevents loss of potency and protects patient safety.

• Unopened vials and pens must be refrigerated at 36–46 °F (2–8 °C) until the expiration date on the label.
• In-use (opened) vials of most insulins can be kept at room temperature (below 77–80 °F, depending on the product) for up to 28 days; always check the package insert for the specific product.
• In-use insulin pens are generally stored at room temperature and must NOT be refrigerated after first use, because temperature cycling can cause dosing problems. Most pens are discarded after 28 days of opening, though some products differ.
• Insulin should never be frozen, stored in direct sunlight, or left in a hot car.
• Technicians must counsel patients or refer them to the pharmacist when questions arise about storage or expiration.

Oral and Injectable Non-Insulin Diabetes Drugs

Type 2 diabetes is often managed with agents that do not require insulin injections.

Metformin (Glucophage) is the first-line oral drug for type 2 diabetes. It decreases glucose production in the liver and improves insulin sensitivity. It does not cause hypoglycemia by itself.

Sulfonylureas (e.g., glipizide, glimepiride, glyburide) stimulate the pancreas to release insulin. Because they increase insulin secretion regardless of blood glucose, hypoglycemia is a real risk.

SGLT-2 inhibitors (e.g., empagliflozin/Jardiance, canagliflozin/Invokana, dapagliflozin/Farxiga) cause the kidneys to excrete excess glucose in the urine. A common side effect is urinary tract or genital yeast infections.

GLP-1 receptor agonists are injectables (some are oral) that stimulate insulin release when blood sugar is elevated and suppress glucagon. Examples include semaglutide (Ozempic injection, Rybelsus oral) and liraglutide (Victoza). They also promote weight loss and slow stomach emptying, which can cause nausea.

DPP-4 inhibitors (e.g., sitagliptin/Januvia) work similarly to GLP-1 agents but are oral and have a milder effect. They carry a low risk of hypoglycemia when used alone.

Thyroid Replacement Drugs

Hypothyroidism (underactive thyroid) is treated with levothyroxine (Synthroid, Levoxyl, others), a synthetic form of thyroxine (T4). It is the most commonly prescribed drug in the United States. Key counseling points include taking it on an empty stomach 30–60 minutes before breakfast and avoiding calcium, iron, or antacids within 4 hours, as these can reduce absorption. Dosing is adjusted based on TSH (thyroid-stimulating hormone) lab values. Because different manufacturers' formulations may not be bioequivalent, substituting brands without prescriber approval can affect therapy; technicians should be alert to generic-to-brand or brand switches.

Corticosteroids

Corticosteroids mimic cortisol, the body's natural stress hormone, and are used to reduce inflammation and suppress the immune system.

Systemic corticosteroids include prednisone, prednisolone, methylprednisolone (Medrol), and dexamethasone. They are used for asthma flares, allergic reactions, autoimmune conditions, and many other inflammatory states. Long-term use causes significant side effects: weight gain, elevated blood sugar, osteoporosis, adrenal suppression, and increased infection risk. Patients on long-term therapy must NOT stop abruptly; doses must be tapered.

Topical and inhaled corticosteroids act locally with fewer systemic effects. Inhaled forms (fluticasone, budesonide) are mainstays of asthma and COPD maintenance; topical forms (hydrocortisone, triamcinolone) treat skin conditions.

Putting It Together

For the PTCE and daily practice, technicians must recognize insulin names and categories, apply correct storage rules, identify major non-insulin diabetes drugs and their mechanisms, know levothyroxine counseling points, and distinguish systemic from inhaled/topical corticosteroids. Always escalate clinical questions to the pharmacist.