CarniSema^®

Semaglutide is a long-acting glucagon-like peptide-1 (GLP-1) receptor agonist with about 94% sequence homology to human GLP-1. Amino-acid substitutions resist DPP-4 degradation, and a C-18 fatty diacid side chain binds albumin, giving once-weekly subcutaneous or once-daily oral dosing.

FDA-approved products are semaglutide injection for subcutaneous use (Ozempic, Wegovy) and semaglutide tablets for oral use (Rybelsus, Ozempic tablets and Wegovy tablets), all from Novo Nordisk. Oral products are not substitutable with one another on a mg-for-mg basis.

Labeled indications of the reference products include the following.

Ozempic (subcutaneous): adjunct to diet and exercise for glycemic control in adults with type 2 diabetes; reduction of major adverse cardiovascular events in adults with type 2 diabetes and established cardiovascular disease; reduction of kidney disease progression, kidney failure and cardiovascular death in adults with type 2 diabetes and chronic kidney disease.

Wegovy (subcutaneous): reduction of major adverse cardiovascular events in adults with established cardiovascular disease and obesity or overweight; with a reduced-calorie diet and increased physical activity, chronic weight management in adults and pediatric patients 12 years and older with obesity, and adults with overweight and a weight-related condition; and noncirrhotic MASH with moderate to advanced fibrosis in adults. Wegovy tablets carry the cardiovascular risk-reduction and chronic weight-management indications in adults only.

Rybelsus and Ozempic tablets (oral): adjunct to diet and exercise for glycemic control in adults with type 2 diabetes, and reduction of major adverse cardiovascular events in adults with type 2 diabetes at high risk for these events. Prescribers also use compounded subcutaneous preparations of semaglutide pursuant to patient-specific prescriptions.

Semaglutide binds and activates the GLP-1 receptor. It increases glucose-dependent insulin secretion, lowers glucagon secretion, delays gastric emptying in the early postprandial phase, and acts on hypothalamic and brainstem appetite centers to reduce food intake. Because insulin release is glucose-dependent, hypoglycemia risk is low unless combined with insulin or a sulfonylurea.

Subcutaneous: absolute bioavailability about 89%; peak concentrations 1 to 3 days after dosing; steady state after 4 to 5 weeks of once-weekly dosing. Oral: bioavailability is about 1% or less and depends on co-formulated SNAC absorption enhancer and fasting administration with a small amount of water.

Volume of distribution is about 12.5 L and plasma protein (albumin) binding exceeds 99%. Semaglutide is metabolized by proteolytic cleavage of the peptide backbone and beta-oxidation of the fatty acid side chain, and is excreted in urine and feces. The elimination half-life is about 1 week. No dose adjustment is labeled for renal or hepatic impairment.

• Personal or family history of medullary thyroid carcinoma or MEN 2.
• Serious hypersensitivity to semaglutide or any excipient.

• Acute pancreatitis, including fatal and nonfatal hemorrhagic or necrotizing cases: discontinue if suspected and do not restart if confirmed.
• Acute gallbladder disease, including cholelithiasis and cholecystitis.
• Hypoglycemia with insulin or an insulin secretagogue; a lower dose of the concomitant agent may be needed.
• Acute kidney injury from dehydration due to nausea, vomiting or diarrhea. Not recommended in severe gastrointestinal disease, including severe gastroparesis.
• Diabetic retinopathy complications in patients with type 2 diabetes, especially with rapid glucose improvement; monitor patients with a history of retinopathy.
• Heart-rate increase (Wegovy); serious hypersensitivity, including anaphylaxis and angioedema. The suicidal behavior and ideation warning was removed from Wegovy labeling in 2026; monitor for depression or mood change as clinically appropriate.
• Pulmonary aspiration during general anesthesia or deep sedation: inform anesthesia providers of use before procedures.
• Nonarteritic anterior ischemic optic neuropathy (NAION) has been reported with semaglutide; it is not a warning in current US labeling. Evaluate sudden vision loss promptly.

• Insulin and sulfonylureas: increased risk of hypoglycemia; consider reducing the dose of the concomitant agent.
• Oral medications: semaglutide delays gastric emptying and may affect the absorption of concomitantly administered oral drugs, notably those with a narrow therapeutic index.
• Levothyroxine: oral semaglutide increased levothyroxine exposure; monitor thyroid parameters.
• Other GLP-1 receptor agonists: do not combine.

The most common adverse reactions are gastrointestinal: nausea, vomiting, diarrhea, constipation, abdominal pain, dyspepsia, eructation, flatulence and gastroesophageal reflux. Others include fatigue, headache, dizziness, injection-site reactions, hypoglycemia in patients with diabetes, increased lipase and amylase, and hair loss. Postmarketing reports include ileus, anaphylaxis and angioedema.

Animal studies showed embryofetal toxicity at clinically relevant exposures, and human data are insufficient. When used for weight reduction, discontinue when pregnancy is recognized, since weight loss offers no benefit in pregnancy. Because of the long washout, discontinue at least 2 months before a planned pregnancy.

No data exist on semaglutide in human milk for the injection. Oral semaglutide is not recommended during breastfeeding because of the SNAC excipient.

Glycemic control (HbA1c, glucose) in patients with diabetes, especially with insulin or a sulfonylurea. Renal function in patients with significant GI fluid loss. Signs of pancreatitis or gallbladder disease. Retinal status in patients with diabetic retinopathy. Heart rate, mood, depression and suicidal thoughts. Symptoms of thyroid tumors. Gastrointestinal tolerance.

• Ozempic (semaglutide) injection Prescribing Information, Novo Nordisk.
• Wegovy (semaglutide) injection and tablets Prescribing Information, Novo Nordisk.
• Rybelsus and Ozempic (semaglutide) tablets Prescribing Information, Novo Nordisk.

Levocarnitine (L-carnitine) is the biologically active L-isomer of carnitine, a quaternary amine synthesized in liver and kidney from lysine and methionine and obtained from dietary meat and dairy. It is required for mitochondrial oxidation of long-chain fatty acids.

FDA-approved products include Carnitor (levocarnitine) tablets, oral solution and injection (Leadiant Biosciences) and generic equivalents.

Oral levocarnitine is FDA-labeled for primary systemic carnitine deficiency and for acute and chronic treatment of inborn errors of metabolism that cause secondary carnitine deficiency.

Intravenous levocarnitine is labeled for those uses and for prevention and treatment of carnitine deficiency in patients with end-stage renal disease on dialysis.

No FDA-labeled dose exists for subcutaneous administration. Prescribers use compounded preparations that include levocarnitine, such as combination subcutaneous injections, pursuant to patient-specific prescriptions.

Levocarnitine combines with long-chain acyl-CoA to form acylcarnitines, which carnitine palmitoyltransferase I, carnitine–acylcarnitine translocase and carnitine palmitoyltransferase II shuttle across the inner mitochondrial membrane for beta-oxidation. It also buffers the mitochondrial acyl-CoA to free CoA ratio and removes excess or toxic acyl groups as urinary acylcarnitines, the basis for its use in organic acidemias.

Oral bioavailability is low, about 15% for tablets and oral solution, because of saturable absorption and gut metabolism; the remainder is degraded by colonic bacteria to trimethylamine (TMA) and gamma-butyrobetaine. After intravenous dosing, levocarnitine distributes into muscle and other tissues, is not bound to plasma proteins and has an elimination half-life of about 17 hours.

Elimination is predominantly renal, with most of an intravenous dose recovered in urine as unchanged carnitine and acylcarnitines; tubular reabsorption is saturable. Subcutaneous absorption has not been characterized in labeling.

• None known (Carnitor labeling lists no contraindications). Hypersensitivity reactions are described under Warnings & Precautions.

• Hypersensitivity: rash, urticaria, facial edema, laryngeal edema and bronchospasm have been reported; discontinue and treat if they occur.
• Seizures have been reported in patients with or without pre-existing seizure activity; patients with a seizure history may have an increase in seizure frequency or severity.
• Renal impairment: chronic high oral doses in severely reduced renal function or in dialysis patients may lead to accumulation of TMA and trimethylamine-N-oxide (TMAO). Use caution and individualize dosing.
• Thyroid: levocarnitine acts as a peripheral antagonist of thyroid hormone entry into cell nuclei and may blunt thyroid hormone effects.

• Warfarin and other coumarins: postmarketing reports of increased INR; monitor INR when starting, changing or stopping levocarnitine.
• Thyroid hormone (levothyroxine, liothyronine): possible reduced effect; monitor thyroid function.
• Valproic acid, pivalate-conjugated antibiotics, and some chemotherapeutic agents (cisplatin, ifosfamide) deplete carnitine; this is a reason for supplementation rather than a hazard.

Oral: nausea, vomiting, abdominal cramps, diarrhea, gastritis and a fishy body odor from TMA. Intravenous (dialysis patients): headache, hypertension, hypotension, nausea, vomiting, diarrhea, paresthesia, fever and other effects that also reflect the underlying disease. Injection-site irritation can occur. Hypersensitivity and seizures are uncommon.

Animal reproduction studies in rats and rabbits showed no evidence of fetal harm; adequate human studies are lacking. Carnitine is a normal endogenous and dietary nutrient, but supplemental doses in pregnancy are given only when clearly needed.

Levocarnitine is a normal component of human milk. The effect of supplemental maternal doses on the breastfed infant has not been studied; consider the infant's total carnitine intake.

In carnitine deficiency, plasma free and total carnitine and the acylcarnitine profile. INR in patients on warfarin. Thyroid function in patients on thyroid hormone. Renal function, and seizure frequency in patients with a seizure history. Gastrointestinal tolerance and body odor.

• Carnitor (levocarnitine) Tablets and Oral Solution Prescribing Information, Leadiant Biosciences.
• Carnitor (levocarnitine) Injection Prescribing Information, Leadiant Biosciences.
• Natural Medicines Comprehensive Database, L-Carnitine monograph.