VONOPRAZAN: 2,019 Adverse Event Reports & Safety Profile

Vonoprazan (as the fumarate), is a potassium-competitive acid blocker. Chemically, it is 1 H -pyrrole-3-methanamine, 5-(2-fluorophenyl)- N -methyl-1-(3-pyridinylsulfonyl)-, (2 E) -2-butenedioate (1:1). Its empirical formula is C 17 H 16 FN 3 O 2 S•C 4 H 4 O 4 with a molecular weight of 461.5. Vonoprazan fumarate has the following structure: Vonoprazan fumarate is white to nearly white crystals or crystalline powder, which melts at 194.8°C. Vonoprazan fumarate is soluble in dimethyl sulfoxide; sparingly soluble in N,N –dimethylacetamide, slightly soluble in N,N -dimethylformamide, methanol, and water; very slightly soluble in ethanol (99.5%); and practically insoluble in 2-propanol, acetone, 1-octanol, and acetonitrile. VOQUEZNA (vonoprazan) tablets are available in two dosage strengths for oral administration: 10 mg of vonoprazan (equivalent to 13.36 mg of vonoprazan fumarate) and 20 mg of vonoprazan (equivalent to 26.72 mg of vonoprazan fumarate). Each film-coated tablet contains the following inactive ingredients: ascorbic acid, croscarmellose sodium, ferric oxide red (only in 20 mg tablets), ferric oxide yellow (only in 10 mg tablets), fumaric acid, hydroxypropyl cellulose, hypromellose, magnesium stearate, mannitol, microcrystalline cellulose, polyethylene glycol 8000, and titanium dioxide. Chemical structure

AND USAGE VOQUEZNA is indicated: for healing of all grades of erosive esophagitis and relief of heartburn associated with erosive esophagitis in adults. to maintain healing of all grades of erosive esophagitis and relief of heartburn associated with erosive esophagitis in adults. for the relief of heartburn associated with non-erosive gastroesophageal reflux disease in adults. in combination with amoxicillin and clarithromycin for the treatment of Helicobacter pylori ( H. pylori ) infection in adults. in combination with amoxicillin for the treatment of H. pylori infection in adults. VOQUEZNA is a potassium-competitive acid blocker indicated: for healing of all grades of erosive esophagitis and relief of heartburn associated with erosive esophagitis in adults. ( 1 ) to maintain healing of all grades of erosive esophagitis and relief of heartburn associated with erosive esophagitis in adults. ( 1 ) for the relief of heartburn associated with non-erosive gastroesophageal reflux disease in adults. ( 1 ) in combination with amoxicillin and clarithromycin for the treatment of Helicobacter pylori (H. pylori) infection in adults. ( 1 ) in combination with amoxicillin for the treatment of H. pylori infection in adults. ( 1 )

AND ADMINISTRATION Recommended Dosage : Healing of Erosive Esophagitis: 20 mg once daily for 8 weeks. ( 2.1 ) Maintenance of Healed Erosive Esophagitis: 10 mg once daily for up to 6 months. ( 2.1 ) Relief of Heartburn Associated with Non-Erosive Gastroesophageal Reflux Disease: 10 mg once daily for 4 weeks. ( 2.1 ) Treatment of H. pylori Infection: see full prescribing information. ( 2.1 ) See also full prescribing information for the recommended dosage by indication for patients with renal or hepatic impairment. ( 2.2 , 2.3 )

Administration

Instructions : Take with or without food. ( 2.4 ) Swallow whole; do not chew or crush. ( 2.4 )

2.1 Recommended Dosage Healing of Erosive Esophagitis The recommended adult oral dosage is VOQUEZNA 20 mg once daily for 8 weeks for the treatment of healing of erosive esophagitis and relief of associated heartburn. Maintenance of Healed Erosive Esophagitis The recommended adult oral dosage is VOQUEZNA 10 mg once daily for up to 6 months for the maintenance of healed erosive esophagitis and relief of associated heartburn. Relief of Heartburn Associated with Non-Erosive Gastroesophageal Reflux Disease The recommended adult oral dosage is VOQUEZNA 10 mg once daily for 4 weeks. Treatment of H. pylori Infection Triple Therapy: The recommended adult oral dosage is VOQUEZNA 20 mg plus amoxicillin 1,000 mg plus clarithromycin 500 mg, each given twice daily (in the morning and evening, 12 hours apart) for 14 days.

Dual

Therapy: The recommended adult oral dose is VOQUEZNA 20 mg given twice daily (in the morning and evening) plus amoxicillin 1,000 mg three times daily (in the morning, mid-day, and evening) for 14 days. Also refer to the amoxicillin and clarithromycin full prescribing information.

2.2 Recommended Dosage in Patients with Renal Impairment Healing of Erosive Esophagitis The recommended dosage of VOQUEZNA in adult patients with renal impairment is described in Table 1 below <span class="opacity-50 text-xs">[see Use in Specific Populations (8.6) and Clinical Pharmacology (12.3) ]</span> .

Table

1: Recommended VOQUEZNA Dosage in Patients with Renal Impairment: Healing of Erosive Esophagitis Estimated glomerular filtration rate (GFR)

Recommended Dosage

30 mL/minute or greater 20 mg once daily Less than 30 mL/minute 10 mg once daily Maintenance of Healed Erosive Esophagitis or Relief of Heartburn Associated with Non-Erosive Gastroesophageal Reflux Disease The recommended dosage of VOQUEZNA in adult patients with renal impairment is the same as for adult patients with normal renal function [see Dosage and Administration (2.1) ] . Treatment of H. pylori Infection The recommended dosage of VOQUEZNA in adult patients with renal impairment is described in Table 2 below [see Use in Specific Populations (8.6) and Clinical Pharmacology (12.3) ].

Table

2: Recommended VOQUEZNA Dosage in Patients with Renal Impairment: Treatment of H. pylori Infection Also refer to the Dosage and Administration section of the amoxicillin and clarithromycin prescribing information for dosage recommendations in patients with renal impairment. Estimated GFR Recommended Dosage 30 mL/minute or greater 20 mg twice daily Less than 30 mL/minute Use is not recommended

2.3 Recommended Dosage in Patients with Hepatic Impairment Healing of Erosive Esophagitis The recommended dosage of VOQUEZNA in adult patients with hepatic impairment is described in Table 3 below <span class="opacity-50 text-xs">[see Use in Specific Populations (8.7) and Clinical Pharmacology (12.3) ]</span> .

Table

3: Recommended VOQUEZNA Dosage in Patients with Hepatic Impairment: Healing of Erosive Esophagitis Classification Recommended Dosage Child-Pugh Class A 20 mg once daily Child-Pugh Class B 10 mg once daily Child-Pugh Class C 10 mg once daily Maintenance of Healed Erosive Esophagitis or Relief of Heartburn Associated with Non-Erosive Gastroesophageal Reflux Disease The recommended dosage of VOQUEZNA in adult patients with hepatic impairment is the same as for patients with normal hepatic function [see Dosage and Administration (2.1) ]. Treatment of H. pylori Infection The recommended dosage of VOQUEZNA in adult patients with hepatic impairment is described in Table 4 below [see Use in Specific Populations (8.7) and Clinical Pharmacology (12.3) ].

Table

4: Recommended VOQUEZNA Dosage in Patients with Hepatic Impairment: Treatment of H. pylori Infection Classification Recommended Dosage Child-Pugh Class A 20 mg twice daily Child-Pugh Class B Use is not recommended Child-Pugh Class C Use is not recommended

2.4 Administration Instructions Take VOQUEZNA with or without food <span class="opacity-50 text-xs">[see Clinical Pharmacology (12.3) ]</span> . Swallow VOQUEZNA tablets whole; do not chew or crush the tablet. Missed doses: For the healing or maintenance of healed erosive esophagitis, or the relief of heartburn associated with non-erosive gastroesophageal reflux disease: If a dose is missed, administer VOQUEZNA as soon as possible within 12 hours after the missed dose. If more than 12 hours have passed, skip the missed dose and administer the next dose at the regularly scheduled time. For the treatment of H. pylori infection: If a dose is missed, administer VOQUEZNA as soon as possible within 4 hours after the missed dose. If more than 4 hours have passed, skip the missed dose and administer the next dose at the regularly scheduled time. Continue the normal dosing schedule until the treatment is completed.

VOQUEZNA is contraindicated in patients with a known hypersensitivity to vonoprazan or any component of VOQUEZNA. Reactions have included anaphylactic shock [see Adverse Reactions (6.2) and Description (11) ] . VOQUEZNA is contraindicated with rilpivirine-containing products [see Drug Interactions (7) ] . For information about contraindications of antibacterial agents (clarithromycin and amoxicillin) indicated in combination with VOQUEZNA, refer to the Contraindications section of the corresponding prescribing information. Known hypersensitivity to vonoprazan or any component of VOQUEZNA. ( 4 ) Rilpivirine-containing products. ( 4 , 7 )

REACTIONS The following serious adverse reactions are described elsewhere in labeling: Acute Tubulointerstitial Nephritis [see Warnings and Precautions (5.2) ] Clostridioides difficile -Associated Diarrhea [see Warnings and Precautions (5.3) ]

Bone

Fracture [see Warnings and Precautions (5.4) ]

Severe Cutaneous Adverse

Reactions [see Warnings and Precautions (5.5) ] Vitamin B12 (Cobalamin) Deficiency [see Warnings and Precautions (5.6) ] Hypomagnesemia and Mineral Metabolism [see Warnings and Precautions (5.7) ]

Fundic Gland

Polyps [see Warnings and Precautions (5.9) ] Most common adverse reactions in VOQUEZNA-treated patients are: Healing of Erosive Esophagitis (≥2%): gastritis, diarrhea, abdominal distension, abdominal pain, and nausea. ( 6.1 ) Maintenance of Healed Erosive Esophagitis (≥3%): gastritis, abdominal pain, dyspepsia, hypertension, and urinary tract infection. ( 6.1 ) Relief of Heartburn Associated with Non-Erosive Gastroesophageal Reflux Disease (≥2%): abdominal pain, constipation, diarrhea, nausea, and urinary tract infection. ( 6.1 ) Treatment of H. pylori Infection (≥2%): diarrhea, dysgeusia, vulvovaginal candidiasis, abdominal pain, headache, hypertension, and nasopharyngitis. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Phathom Pharmaceuticals, Inc. at toll-free phone 1-888-775-7428 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Healing of Erosive Esophagitis and Maintenance of Healed Erosive Esophagitis The safety of VOQUEZNA was evaluated in a randomized, active-controlled, double-blind two phase trial for the healing of erosive esophagitis (2 to 8 weeks) and maintenance of healed erosive esophagitis (through 24 weeks) conducted in the United States and Europe <span class="opacity-50 text-xs">[see Clinical Studies (14.1) , (14.2) ]</span> . Adverse reactions reported in at least 2% of patients in the VOQUEZNA 20 mg once daily arm in the healing phase are presented in Table 5 .

Table

5: Adverse Reactions Reported in at least 2% of patients in the VOQUEZNA arm. in a Clinical Trial of Adult Patients with All Grades of Erosive Esophagitis The trial was not designed to support comparative claims for VOQUEZNA for the adverse reactions reported in this table. (2 to 8 Week Healing Phase)

Adverse

Reactions VOQUEZNA 20 mg Once Daily N=514 % Lansoprazole 30 mg Once Daily N=510 % Gastritis Represents a grouped term and includes related terms. 3 2 Diarrhea 2 3 Abdominal distension 2 1 Abdominal pain 2 1 Nausea 2 1 Adverse reactions reported in at least 3% of patients in the VOQUEZNA 10 mg once daily arm of the maintenance phase are shown in Table 6 .

Table

6: Adverse Reactions Reported in at least 3% of patients in the VOQUEZNA arm. in a Clinical Trial of Adult Patients with All Grades of Erosive Esophagitis The trial was not designed to support comparative claims for VOQUEZNA for the adverse reactions reported in this table. (24 Week Maintenance Phase)

Adverse

Reactions VOQUEZNA 10 mg Once Daily N=296 % Lansoprazole 15 mg Once Daily N=297 % Gastritis Represents a grouped term and includes related terms. 6 3 Abdominal pain 4 2 Dyspepsia 4 3 Hypertension 3 2 Urinary tract infection 3 2 COVID-19 COVID-19 was reported in the healing phase in 11 (2%) VOQUEZNA-treated patients and 9 (2%) lansoprazole-treated patients, and in the maintenance phase in 18 (6%) VOQUEZNA-treated patients and 20 (7%) lansoprazole-treated patients.

Other Clinical

Trials of Erosive Esophagitis Adverse reactions reported in the United States trial were similar to those reported in 4 additional randomized, active-controlled, double-blind studies of vonoprazan compared to lansoprazole conducted outside of the United States (two 8-week trials of healing of erosive esophagitis and two 24-week maintenance of healed erosive esophagitis trials). Relief of Heartburn Associated with Non-Erosive Gastroesophageal Reflux Disease The safety of VOQUEZNA 10 mg once daily for the relief of heartburn associated with non-erosive gastroesophageal reflux disease was evaluated in a randomized, placebo-controlled, double-blind, four-week trial with a 20-week extension phase conducted in the United States [see Clinical Studies (14.3) ] . Patients initially randomized to placebo in the 4-week placebo-controlled phase were re-randomized to VOQUEZNA 10 mg once daily or a higher dosage of VOQUEZNA for 20 weeks in the extension phase. Adverse reactions reported in at least 2% of patients in the VOQUEZNA 10 mg once daily arm in the 4-week placebo-controlled phase are presented in Table 7 .

Table

7: Adverse Reactions Reported in at least 2% of patients in the VOQUEZNA arm. in a Clinical Trial of Adult Patients with Non-Erosive Gastroesophageal Reflux Disease (4-week Placebo-Controlled Phase)

Adverse

Reactions VOQUEZNA 10 mg Once Daily N=259 % Placebo Once Daily N=256 % Abdominal pain Represents a grouped term and includes related terms. 2 2 Constipation 2 1 Diarrhea 2 1 Nausea 2 <1 Urinary tract infection 2 1 Other adverse reactions: Upper respiratory tract infection (4%) and sinusitis (3%) were reported in patients who received VOQUEZNA 10 mg once daily in the 20-week extension phase. COVID-19 COVID-19 was reported in the 4-week placebo-controlled phase in 3 (1%) patients who received VOQUEZNA 10 mg once daily and 3 (1%) patients who received placebo, and in 24 (7%) patients who received VOQUEZNA 10 mg once daily in the 20-week extension phase.

Less Common Adverse Reactions

Adverse reactions reported in 1% or less of VOQUEZNA-treated patients for the healing or maintenance of healed erosive esophagitis or for the relief of heartburn associated with non-erosive gastroesophageal reflux disease in the United States trials are: Blood and lymphatic system disorders: anemia, lymphocytosis Cardiac disorders: tachycardia Ear and labyrinth disorders: vertigo Gastrointestinal disorders: duodenal polyp, dry mouth, dysphagia, eructation, flatulence, gastric polyps, vomiting General disorders and administrative site conditions: asthenia, peripheral edema Investigations: increased liver enzymes Metabolism and nutritional disorders: diabetes mellitus Musculoskeletal system: bone fracture Nervous system disorders: dizziness, headache, syncope Psychiatric disorders: depression, insomnia Renal and urinary disorders: tubulointerstitial nephritis Skin and subcutaneous tissue disorders: eczema, rash, urticaria Treatment of H. pylori Infection The safety of VOQUEZNA, amoxicillin and clarithromycin was evaluated in 675 adult patients (aged 20 to 82 years) in clinical trials in the United States, Europe, and Japan, and VOQUEZNA and amoxicillin was evaluated in 348 adult patients (aged 20 to 80 years) in a clinical trial in the United States and Europe. All of the patients were screened and found to be positive for H. pylori infection. The safety of VOQUEZNA, amoxicillin, and clarithromycin (triple therapy) and VOQUEZNA and amoxicillin (dual therapy) was evaluated in a randomized, controlled, double-blind (triple therapy)/open-label (dual therapy) study conducted in the United States and Europe in treatment-naïve H. pylori -positive adult patients [see Clinical Studies (14.4) ] .

Adverse Reactions

Leading to Discontinuation Treatment discontinuation due to an adverse reaction occurred in 2.3% (8/346) of the patients treated with VOQUEZNA, amoxicillin, and clarithromycin; 0.9% (3/348) of the patients treated with VOQUEZNA and amoxicillin; and 1.2% (4/345) of the patients treated with lansoprazole, amoxicillin, and clarithromycin. The most common adverse reactions leading to discontinuation of VOQUEZNA, amoxicillin, and clarithromycin were diarrhea (0.6%) and hypertension (0.6%), and the most common adverse reaction leading to discontinuation of VOQUEZNA and amoxicillin was rash (0.6%).

Most Common Adverse Reactions

Adverse reactions reported in at least 2% of patients in any treatment arm are described in Table 8 .

Table

8: Adverse Reactions Reported in at least 2% of patients in any treatment arm. in Adult Patients with H. pylori Infection These trials were not designed to support comparative claims for VOQUEZNA-containing treatment arms for the adverse reactions reported in this table.

Adverse

Reactions VOQUEZNA and Amoxicillin VOQUEZNA, Amoxicillin, and Clarithromycin Lansoprazole, Amoxicillin, and Clarithromycin N=348 % N=346 % N=345 % Diarrhea 5 4 10 Dysgeusia Represents a grouped term and includes related terms. 1 5 6 Vulvovaginal candidiasis 2 3 1 Abdominal pain 3 2 3 Headache 1 3 1 Hypertension 1 2 1 Nasopharyngitis 2 <1 1 Less Common Adverse Reactions Other adverse reactions reported in less than 2% of patients treated with VOQUEZNA, amoxicillin, and clarithromycin or VOQUEZNA and amoxicillin are listed below by body system: Blood and lymphatic system disorders: anemia, leukocytosis, leukopenia, neutropenia Cardiac disorders: QT prolongation, tachycardia Eye disorders: orbital edema Gastrointestinal disorders: abdominal distension, constipation, dry mouth, duodenal polyp, duodenal ulcer, dyspepsia, flatulence, gastric ulcer, gastroesophageal reflux disease, hematochezia, large intestine polyp, rectal polyp, nausea, stomatitis, tongue discomfort, vomiting General disorders and administration site conditions: fatigue, pyrexia Immune system disorders: drug hypersensitivity Infections and infestations: anal fungal infection, gastrointestinal viral infection, oral fungal infection, pneumonia, tongue fungal infection, upper respiratory tract infection, urinary tract infection, viral infection Investigations: increased liver function test Metabolism and nutrition disorders: decreased appetite Musculoskeletal system: bone fracture Nervous system disorders: ageusia, dizziness, tension headache Psychiatric disorders: anxiety, depression, insomnia Renal and urinary disorders: renal hypertrophy, tubulointerstitial nephritis Reproductive system and breast disorders: vaginal discharge Respiratory, thoracic and mediastinal disorders: cough, nasal polyps, oropharyngeal pain Skin and subcutaneous tissue disorders: dermatitis, dry skin, rash For more information on adverse reactions and laboratory changes with amoxicillin or clarithromycin, refer to the Adverse Reactions section of the corresponding prescribing information.

6.2 Postmarketing Experience The following additional adverse reactions have been identified during post-approval use of vonoprazan outside of the United States. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Blood and lymphatic system disorders: thrombocytopenia Immune system disorders: anaphylactic shock <span class="opacity-50 text-xs">[see Contraindications (4) ]</span> Infections and infestations: C. difficile (with concomitant antibacterials) Investigation: hypomagnesemia, hypokalemia, hypocalcemia, vitamin B12 deficiency Hepatobiliary disorders: hepatic injury, hepatic failure, jaundice Skin and subcutaneous tissue disorders: drug eruption, erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis

AND PRECAUTIONS Gastric Malignancy : Symptomatic response to treatment does not preclude the presence of gastric malignancy; consider additional follow-up and diagnostic testing. ( 5.1 )

Acute Tubulointerstitial

Nephritis : Discontinue treatment and evaluate patients. ( 5.2 ) Clostridioides difficile -Associated Diarrhea (CDAD) : May be associated with an increased risk; use the shortest duration of treatment appropriate to the condition. ( 5.3 )

Bone

Fracture, including Osteoporosis-related Fracture : Use the shortest duration of treatment appropriate to the condition. ( 5.4 )

Severe Cutaneous Adverse

Reactions : Discontinue at the first signs or symptoms of severe cutaneous adverse reactions or other signs of hypersensitivity and consider further evaluation. ( 5.5 ) Vitamin B12 (Cobalamin) Deficiency : Long-term use may lead to malabsorption or deficiency; consider further workup if clinical symptoms are present. ( 5.6 ) Hypomagnesemia and Mineral Metabolism : Hypomagnesemia may lead to hypocalcemia and/or hypokalemia. Consider monitoring magnesium and calcium levels in at-risk patients, or if there is concomitant use of digoxin or other drugs that cause hypomagnesemia. ( 5.7 ) Interactions with Investigations for Neuroendocrine Tumors : Increased chromogranin A (CgA) levels may interfere with diagnostic investigations; temporarily stop VOQUEZNA at least 4 weeks before assessing CgA levels. ( 5.8 , 7 )

Fundic Gland

Polyps : Risk increases with long-term use; use the shortest duration of treatment appropriate to the condition. ( 5.9 )

5.1 Presence of Gastric Malignancy In adults, symptomatic response to therapy with VOQUEZNA does not preclude the presence of gastric malignancy. Consider additional follow-up and diagnostic testing in patients who have a suboptimal response or an early symptomatic relapse after completing treatment with VOQUEZNA. In older patients, also consider endoscopy.

5.2 Acute Tubulointerstitial Nephritis Acute tubulointerstitial nephritis (TIN) has been reported with VOQUEZNA <span class="opacity-50 text-xs">[see Adverse Reactions (6.1) ]</span> . If suspected, discontinue VOQUEZNA and evaluate patients with suspected acute TIN.

5.3 Clostridioides difficile -Associated Diarrhea Published observational studies suggest that proton pump inhibitors (PPIs) may be associated with an increased risk of Clostridioides difficile -associated diarrhea (CDAD), especially in hospitalized patients. VOQUEZNA, another drug that blocks the proton pump to inhibit gastric acid production, may also increase the risk of CDAD. Consider CDAD in patients with diarrhea that does not improve <span class="opacity-50 text-xs">[see Adverse Reactions (6.2) ]</span> . Use the shortest duration of VOQUEZNA appropriate to the condition being treated. CDAD has been reported with use of nearly all antibacterial agents. For more information specific to antibacterial agents (clarithromycin and amoxicillin) indicated for use in combination with VOQUEZNA, refer to the Warnings and Precautions section of the corresponding prescribing information.

5.4 Bone Fracture Several published observational studies suggest that PPI therapy may be associated with an increased risk for osteoporosis-related fractures of the hip, wrist, or spine. The risk of fracture was increased in patients who received high-dose, defined as multiple daily doses, and long-term therapy (a year or longer). Bone fracture, including osteoporosis-related fracture, has also been reported with vonoprazan. Use the shortest duration of VOQUEZNA appropriate to the condition being treated <span class="opacity-50 text-xs">[see Dosage and Administration (2.1) ]</span>. Patients at risk for osteoporosis-related fractures should be managed according to the established treatment guidelines .

5.5 Severe Cutaneous Adverse Reactions Severe cutaneous adverse reactions, including Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) have been reported with VOQUEZNA <span class="opacity-50 text-xs">[see Adverse Reactions (6.2) ]</span> . Discontinue VOQUEZNA at the first signs or symptoms of severe cutaneous adverse reactions or other signs of hypersensitivity and consider further evaluation.

5.6 Vitamin B12 (Cobalamin)

Deficiency

Long-term use of acid-suppressing drugs can lead to malabsorption of Vitamin B12 caused by hypo- or achlorhydria. Vitamin B12 deficiency has been reported postmarketing with vonoprazan [see Adverse Reactions (6.2) ]. If clinical symptoms consistent with Vitamin B12 deficiency are observed in patients treated with VOQUEZNA consider further workup.

5.7 Hypomagnesemia and Mineral Metabolism Hypomagnesemia has been reported postmarketing with vonoprazan <span class="opacity-50 text-xs">[see Adverse Reactions (6.2) ]</span> . Hypomagnesemia may lead to hypocalcemia and/or hypokalemia and may exacerbate underlying hypocalcemia in at-risk patients. Consider monitoring magnesium levels prior to initiation of VOQUEZNA and periodically in patients expected to be on prolonged treatment, in patients taking drugs that may have increased toxicity in the presence of hypomagnesemia (e.g., digoxin), or drugs that may cause hypomagnesemia (e.g., diuretics). Treatment of hypomagnesemia may require magnesium replacement and discontinuation of VOQUEZNA. Consider monitoring magnesium and calcium levels prior to initiation of VOQUEZNA and periodically while on treatment in patients with a preexisting risk of hypocalcemia (e.g., hypoparathyroidism). Supplement with magnesium and/or calcium, as necessary. If hypocalcemia is refractory to treatment, consider discontinuing VOQUEZNA.

5.8 Interactions with Diagnostic Investigations for Neuroendocrine Tumors Serum chromogranin A (CgA) levels increase secondary to drug-induced decreases in gastric acidity. The increased CgA level may cause false positive results in diagnostic investigations for neuroendocrine tumors. Temporarily discontinue VOQUEZNA treatment at least 4 weeks before assessing CgA levels and consider repeating the test if initial CgA levels are high. If serial tests are performed (e.g., for monitoring), the same commercial laboratory should be used for testing, as reference ranges between tests may vary <span class="opacity-50 text-xs">[see Drug Interactions (7) and Clinical Pharmacology (12.2) ]</span> .

5.9 Fundic Gland Polyps Use of VOQUEZNA is associated with a risk of fundic gland polyps that increases with long-term use, especially beyond one year. Fundic gland polyps have been reported with vonoprazan in clinical trials and postmarketing use with PPIs. Most patients who developed fundic gland polyps were asymptomatic and fundic gland polyps were identified incidentally on endoscopy. Use the shortest duration of VOQUEZNA appropriate to the condition being treated <span class="opacity-50 text-xs">[see Dosage and Administration (2.1) ]</span> .

INTERACTIONS Table 9 and Table 10 include drugs with clinically important drug interactions and interaction with diagnostics when administered concomitantly with VOQUEZNA and instructions for preventing or managing them. These recommendations are based on either drug interaction trials or predicted interactions due to the expected magnitude of interaction and potential for serious adverse reactions or loss of efficacy [see Clinical Pharmacology (12.3) ] . Consult the labeling of concomitantly used drugs to obtain further information about interactions with vonoprazan.

Table

9: Drug Interactions Affecting Drugs Co-Administered with VOQUEZNA and Interactions with Diagnostics Drugs Dependent on Gastric pH for Absorption Antiretrovirals Clinical Effect Vonoprazan reduces intragastric acidity [see Clinical Pharmacology (12.2) ], which may alter the absorption of antiretroviral drugs, leading to changes in the safety and/or effectiveness. Prevention or Management Rilpivirine-containing products Concomitant use with VOQUEZNA is contraindicated .

Atazanavir

Avoid concomitant use with VOQUEZNA.

Nelfinavir

Other antiretrovirals See the prescribing information of other antiretroviral drugs dependent on gastric pH for absorption prior to concomitant use with VOQUEZNA.

Other

Drugs (e.g., iron salts, erlotinib, dasatinib, nilotinib, mycophenolate mofetil, ketoconazole/itraconazole)

Clinical Effect

Vonoprazan reduces intragastric acidity [see Clinical Pharmacology (12.2) ] , which may decrease the absorption of drugs reducing their effectiveness. Prevention or Management See the prescribing information for other drugs dependent on gastric pH for absorption.

Combination

Therapy with Clarithromycin and/or Amoxicillin Clinical Effect Concomitant administration of clarithromycin with other drugs can lead to serious adverse reactions, including potentially fatal arrhythmias, and is contraindicated. Amoxicillin also has drug interactions. Prevention or Management See Contraindications and Warnings and Precautions in the prescribing information for clarithromycin.

See Drug

Interactions in the prescribing information for amoxicillin. Certain CYP3A Substrates Where Minimal Concentration Changes May Lead to Serious Toxicities Clinical Effect Vonoprazan is a weak CYP3A inhibitor [see Clinical Pharmacology (12.3) ] . Vonoprazan may increase exposure of CYP3A4 substrates, which may increase the risk of adverse reactions related to these substrates. Prevention or Management Frequently monitor concentrations and/or adverse reactions related to the substrate drugs when used with VOQUEZNA. Dosage reduction of substrate drugs may be needed. See prescribing information for the relevant substrate drugs. CYP2C19 Substrates (e.g., clopidogrel, citalopram, cilostazol)

Clinical Effect

Vonoprazan is a CYP2C19 inhibitor [see Clinical Pharmacology (12.3) ] . Vonoprazan may reduce plasma concentrations of the active metabolite of clopidogrel and may cause reduction in platelet inhibition. Vonoprazan may increase exposure of CYP2C19 substrate drugs (e.g., citalopram, cilostazol). Prevention or Management Clopidogrel Carefully monitor the efficacy of clopidogrel and consider alternative anti-platelet therapy. Citalopram and Cilostazol Carefully monitor patients for adverse reactions associated with citalopram and cilostazol. See the prescribing information for dosage adjustments.

Chromogranin

Test for Neuroendocrine Tumors Clinical Effect Vonoprazan reduces intragastric acidity [see Clinical Pharmacology (12.2) ] , which increases CgA levels and may cause false positive results in diagnostic investigations for neuroendocrine tumors . Prevention or Management Assess CgA levels at least 4 weeks after stopping VOQUEZNA treatment and repeat the test if initial CgA levels are high. If serial tests are performed (e.g., for monitoring), use the same commercial laboratory for testing, as reference ranges between tests may vary. Interaction with Secretin Stimulation Test Clinical Effect Hyper-response in gastrin secretion in response to secretin stimulation test, falsely suggesting gastrinoma. Prevention or Management Temporarily stop VOQUEZNA at least 4 weeks before assessing to allow gastrin levels to return to normal [see Clinical Pharmacology (12.2) ] .

Table

10: Drug Interactions Affecting VOQUEZNA When Co-Administered with Other Drugs Strong or Moderate CYP3A4 Inducers Clinical Effect Vonoprazan is a CYP3A substrate. Strong or moderate CYP3A inducers decrease vonoprazan exposure [see Clinical Pharmacology (12.3) ], which may reduce the effectiveness of VOQUEZNA. Prevention or Management Avoid concomitant use with VOQUEZNA. See full prescribing information for a list of clinically important drug interactions. ( 7 )