Feline Systemic Hypertension: Screening and Management

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-08-11

Key Takeaways

• Systemic hypertension in cats is primarily secondary to chronic kidney disease or hyperthyroidism, with geriatric cats being the most susceptible population. Screening is recommended for cats ≥9 years old, or younger cats with predisposing conditions, and diagnosis is confirmed by systolic blood pressure consistently above 160 mmHg with repeat measurements.
• Accurate blood pressure measurement requires a quiet environment, a calm patient, and consistent technique, typically using Doppler or oscillometric devices on the forelimb or hindlimb, with multiple readings averaged. Target blood pressure is generally below 160 mmHg systolic, ideally below 150 mmHg, with a lower target in cats with proteinuria or progressive renal injury.
• Ocular complications, including hypertensive retinopathy, choroidopathy, and optic neuropathy, are common target organ damage and necessitate funduscopic examination at diagnosis and each recheck; retinal detachment or hemorrhage warrants prompt treatment initiation.
• Amlodipine besylate is the first-line oral antihypertensive therapy, titrated to effect, with telmisartan serving as an alternative agent, particularly in cats with concurrent chronic kidney disease for potential renoprotective benefits.
• Monitoring involves rechecking blood pressure every 1-2 weeks after treatment initiation or dose change, then every 3-6 months, alongside regular assessment of fundic changes, renal parameters (creatinine, UP:C ratio), and total thyroxine in hyperthyroid cats.
• Incomplete blood pressure control, progressive azotaemia, and ocular complications are recognized failure modes, underscoring the importance of consistent monitoring and prompt intervention, with referral to specialists indicated for refractory hypertension or severe target organ damage.

Systemic hypertension in cats is a common, progressive disorder of older patients, most frequently encountered as a complication of chronic kidney disease or hyperthyroidism. This article provides a practical framework for the practicing veterinarian covering blood pressure measurement technique, patient selection for screening, diagnostic staging, first-line and adjunctive drug therapy, and long-term therapeutic monitoring. The content assumes familiarity with routine feline internal medicine and focuses on the outpatient management of stable hypertensive disease. Emergency hypertensive crisis, defined as acute, severe target organ injury requiring immediate hospitalization, is excluded from this discussion.

The clinical question this article answers is direct: which cats should have blood pressure measured, how should those measurements be interpreted, and what treatment and monitoring plan produces the best long-term outcome? The evidence base draws on prospective clinical trials, retrospective case series, and expert consensus statements from veterinary internal medicine specialty bodies. Where the literature is limited or conflicting, this is stated explicitly.

At a Glance

Pathophysiology of Feline Systemic Hypertension

Mechanisms of Blood Pressure Elevation

Feline hypertension is classified as primary (essential) or secondary, with secondary causes predominating in clinical practice. Chronic kidney disease is the most common underlying condition, followed by hyperthyroidism. The relationship between renal disease and hypertension is bidirectional: renal dysfunction impairs sodium and water excretion and activates pressor systems, while sustained hypertension accelerates renal injury through glomerular capillary damage and proteinuria. Jepson's review of classification and pathogenesis describes the geriatric cat as the most susceptible population and emphasizes that routine blood pressure monitoring is often advocated as part of a health screen in older cats.

The renin-angiotensin-aldosterone system (RAAS) contributes to blood pressure regulation in cats, but its role in established feline hypertension is not straightforward. A prospective study of 196 cats over 9 years of age examined plasma renin activity (PRA) and plasma aldosterone concentrations (PAC) in normotensive and hypertensive cats with and without azotemia. The study by Jepson, Syme, and Elliott found that hypertensive cats demonstrated significantly increased PAC with decreased PRA compared with normotensive cats. This pattern, a low-renin, high-aldosterone state, resembles that seen in some forms of human primary aldosteronism. The authors noted that additional work is required to determine whether this reflects autonomous aldosterone production or activation of the RAAS without a demonstrable increase in PRA.

Target Organ Damage

Sustained hypertension damages the eye, kidney, cardiovascular system, and central nervous system. The eye is particularly vulnerable because the feline retina has a high metabolic demand and the choroidal vasculature is poorly autoregulated. Crispin and Mould's review of the feline fundus in hypertensive disease categorises ocular changes into hypertensive retinopathy, hypertensive choroidopathy, and hypertensive optic neuropathy. Retinal detachment, hyphaema, and retinal hemorrhage are common presenting findings in cats with undiagnosed hypertension, and sudden-onset blindness may be the first clinical sign noticed by an owner.

Renal damage from hypertension manifests as progressive azotemia and proteinuria. The relationship between hypertension and proteinuria has been explored in recent studies, and the presence of proteinuria may indicate more severe hypertensive renal injury. Cardiac changes include left ventricular hypertrophy and a gallop rhythm or murmur on auscultation, although these findings are nonspecific in older cats.

Blood Pressure Measurement

Technique and Equipment

Accurate blood pressure measurement requires a quiet environment, a calm patient, and a consistent technique. Stepien's clinical review of diagnosis and management identifies obtaining accurate measurements in anxious, fractious, or uncooperative cats as a significant issue in feline medicine. Doppler ultrasonography is the most widely used method in practice because it tolerates patient movement better than oscillometric devices. Oscillometric devices are acceptable but may underestimate blood pressure in some patients, particularly at higher pressures.

The cuff should be placed on the forelimb or hindlimb and should have a width of approximately 30 to 40 percent of the limb circumference. The cat should be allowed to settle for several minutes before measurement begins. Five to seven consecutive readings should be taken, and the first reading is often discarded because it tends to be elevated due to handling stress. The mean of the remaining readings is recorded. The same limb and cuff size should be used at each visit to allow meaningful comparison over time.

Interpretation and Classification

Systolic blood pressure is the primary parameter used for diagnosis and monitoring in cats. Diastolic pressure is less reliably measured with indirect techniques and is not used for treatment decisions. A single elevated reading is insufficient for diagnosis. Hypertension should be confirmed by repeated measurements on separate occasions, or by a single session with consistently elevated readings in a cat with compatible target organ damage.

The ACVIM consensus statement on feline hypertension defines hypertension as systolic blood pressure persistently above 160 mmHg. Blood pressure between 150 and 160 mmHg is considered borderline and warrants monitoring, particularly in cats with concurrent renal disease or hyperthyroidism. Blood pressure above 180 mmHg carries a high risk of target organ damage and justifies immediate treatment even in the absence of detectable ocular or renal changes.

Screening Protocol for Feline Systemic Hypertension

Screening for systemic hypertension should be a routine component of preventive healthcare in cats aged nine years and older, as the geriatric cat appears most susceptible to the development of this condition Jepson on classification and pathogenesis. The same applies to younger cats with conditions known to predispose to hypertension, including chronic kidney disease, hyperthyroidism, and prior diagnosis of hypertensive target organ damage. Screening is also indicated in any cat with unexplained proteinuria, retinal hemorrhage or detachment, acute onset blindness, or cardiac murmurs in the absence of other explanation.

Blood pressure measurement should be performed at every wellness examination in at-risk populations. A single normal reading does not exclude hypertension, particularly in cats that are anxious or difficult to restrain. Serial measurements over multiple visits provide the most reliable basis for diagnosis and treatment decisions. Cats with borderline elevations should be rechecked within two to four weeks, while cats with sustained readings above 180 mmHg require prompt diagnostic evaluation and therapeutic planning.

The screening sequence follows a defined structure. First, obtain a complete history with attention to polyuria, polydipsia, weight loss, appetite changes, and visual deficits. Second, perform a thorough physical examination including fundic examination, cardiac auscultation, and palpation of the thyroid glands. Third, measure systolic blood pressure using the technique described in the previous section. Fourth, collect baseline laboratory data including serum biochemistry, complete blood count, urinalysis, and total thyroxine concentration in cats over six years of age. Fifth, assess urine protein-to-creatinine ratio in cats with evidence of renal disease or proteinuria on routine urinalysis.

The decision to initiate antihypertensive therapy depends on the magnitude of blood pressure elevation and the presence of target organ damage. Cats with systolic blood pressure consistently above 160 mmHg in the presence of hypertensive retinopathy, hypertensive choroidopathy, or other evidence of target organ damage warrant treatment. Cats with systolic blood pressure above 170 to 180 mmHg without detectable target organ damage also warrant treatment, given the risk of progression to blindness or accelerated renal injury. Cats with readings between 150 and 170 mmHg and no evidence of target organ damage should be monitored closely, with repeat measurement within two to four weeks and continued surveillance for the development of complications.

Diagnostic Evaluation and Staging

The diagnostic evaluation of a hypertensive cat serves two purposes: confirming the presence of sustained hypertension and identifying the underlying cause. Fundoscopic examination is essential in every hypertensive cat, as the retinal and choroidal changes of hypertension may be present even when visual deficits are not reported by the owner. The fundus changes fall into three categories: hypertensive retinopathy, hypertensive choroidopathy, and hypertensive optic neuropathy Crispin and Mould on the feline fundus. Retinopathy includes generalized or focal retinal arteriolar constriction, retinal hemorrhage, and retinal edema. Choroidopathy manifests as bullous retinal detachment with associated subretinal fluid. Optic neuropathy presents as optic disc edema and peripapillary hemorrhage.

Chronic kidney disease is the most commonly identified underlying condition in hypertensive cats. In one series of 30 hypertensive cats, 16 were in chronic renal failure at diagnosis Elliott and colleagues on clinical findings and treatment response. Hyperthyroidism is the second major cause, and concurrent disease is possible. Cats with untreated hyperthyroidism may have hypertension that resolves with thyroid treatment alone, but cats that remain hypertensive after euthyroidism is achieved require antihypertensive therapy. Primary or idiopathic hypertension is diagnosed when no underlying cause is identified after thorough investigation.

The relationship between hypertension and renal disease is bidirectional. Hypertension can accelerate renal damage through glomerular capillary injury, and renal disease can cause hypertension through sodium retention, activation of the renin-angiotensin-aldosterone system, and reduced vasodilatory capacity. Proteinuria should be assessed in all hypertensive cats, as it reflects glomerular injury and carries prognostic significance. Hypertensive cats demonstrate significantly increased plasma aldosterone concentrations with decreased plasma renin activity compared with normotensive cats, and the role of aldosterone in the pathogenesis of feline hypertension remains an area of active investigation Jepson and colleagues on plasma renin activity and aldosterone.

Pharmacological Management

Amlodipine besylate is the first-line antihypertensive agent in cats. It is a dihydropyridine calcium channel blocker that produces arteriolar vasodilation with minimal negative inotropic effect. In the series of 30 hypertensive cats treated with amlodipine, systolic blood pressure decreased from a mean of 202.5 mmHg to 153.2 mmHg within the first 50 days of treatment Elliott and colleagues on clinical findings and treatment response. Blood pressure was maintained below a target of 165 mmHg in 58 per cent of cases treated for three months or longer, and amlodipine was used successfully for long-term control.

Amlodipine is administered orally once daily. The starting dose should be selected according to current formulary and label references, and the response assessed by repeat blood pressure measurement within one to two weeks. Dose escalation is guided by measured blood pressure response and tolerance. Most cats tolerate amlodipine well, and adverse effects are uncommon. Reflex tachycardia is rarely clinically significant in cats.

Telmisartan is an angiotensin II receptor blocker that provides an alternative to amlodipine. In a double-blind, placebo-controlled, randomised trial, telmisartan administered orally produced a clinically relevant decrease in systolic blood pressure of approximately 24 mmHg by day 28 in hypertensive cats with baseline systolic blood pressure of 160 to 200 mmHg Coleman and colleagues on telmisartan efficacy. Telmisartan may be considered as a first-line agent, particularly in cats with concurrent chronic kidney disease where blockade of the renin-angiotensin-aldosterone system may confer additional renoprotective effects. The choice between amlodipine and telmisartan depends on clinician preference, patient factors, and cost. Amlodipine has the longest track record and the most extensive published evidence base in feline hypertension.

ACE inhibitors such as benazepril and enalapril are less effective as sole antihypertensive agents in cats and are generally reserved for combination therapy or for management of proteinuria. They may be added to amlodipine when blood pressure control is inadequate or when persistent proteinuria requires additional intervention.

Treatment Monitoring Plan

Monitoring after initiation of antihypertensive therapy follows a structured schedule. Blood pressure should be rechecked one to two weeks after starting treatment or after any dose change. The goal is to achieve systolic blood pressure below 160 mmHg, with a lower target of 140 to 150 mmHg in cats with proteinuria or evidence of progressive renal injury. The target value of 165 mmHg used in earlier studies reflects the measurement techniques and clinical standards of that era Elliott and colleagues on clinical findings and treatment response, and current consensus guidance from the American College of Veterinary Internal Medicine supports a lower treatment target ACVIM consensus statements.

Amlodipine treatment is associated with a significant increase in plasma renin activity, reflecting activation of the renin-angiotensin-aldosterone system in response to blood pressure reduction Jepson and colleagues on plasma renin activity and aldosterone. This finding has clinical relevance because it suggests that combination therapy with a RAAS-blocking agent may be physiologically rational in cats that do not achieve adequate blood pressure control with amlodipine alone.

Cats that fail to achieve target blood pressure with amlodipine monotherapy should first have their dose increased according to formulary guidance. If blood pressure remains elevated at the maximum tolerated dose, telmisartan or an ACE inhibitor may be added. Poor owner compliance, difficulty administering medication, and measurement artefact from stress should be excluded before concluding that drug resistance is present.

Documentation and Follow-up

Accurate documentation of blood pressure measurements, drug doses, and clinical findings is essential for longitudinal management. Each blood pressure reading should be recorded with the measurement technique, cuff size, site of measurement, number of readings obtained, and the cat's demeanour during measurement. This allows comparison of readings across visits and identification of trends that might otherwise be obscured by day-to-day variability.

Follow-up intervals should be individualised. Cats with stable blood pressure control and no evidence of target organ damage can be rechecked every three months. Cats with recent dose changes, active retinopathy, progressive renal disease, or concurrent hyperthyroidism require more frequent monitoring, typically every two to four weeks until stability is achieved. Cats with chronic kidney disease require ongoing monitoring of renal parameters, as blood pressure reduction can transiently decrease glomerular filtration rate and increase serum creatinine concentration. This effect is usually mild and acceptable given the long-term benefits of blood pressure control, but it should be anticipated and discussed with the owner.

The prognosis for hypertensive cats depends on the underlying cause, the presence and severity of target organ damage at diagnosis, and the response to treatment. Cats with retinal detachment at presentation may regain vision if blood pressure is controlled promptly, although the degree of recovery is variable. Long-term survival is influenced primarily by the progression of concurrent renal disease.

Recognized Complications and Failure Modes

The most consequential failure in managing feline hypertension is incomplete blood pressure control with ongoing silent target organ damage. In the landmark series of 30 hypertensive cats treated with amlodipine, systolic blood pressure remained below 165 mmHg in only 58 per cent of cases treated for three months or longer, a result that underscores how frequently first-line therapy alone is insufficient Elliott et al., feline hypertension clinical findings and response to antihypertensive treatment. Early detection depends on scheduled recheck visits with repeat blood pressure measurement, not on owner observation, since most cats show no behavioral sign of persistent elevation.

Ocular complications deserve particular attention. Hypertensive retinopathy, choroidopathy, and optic neuropathy can progress to retinal detachment and blindness even when owners report no visual deficit Crispin and Mould, systemic hypertensive disease and the feline fundus. Funduscopic examination at every recheck, including the contralateral eye in a cat with unilateral lesions, is the only reliable method for early detection. A cat with a previously normal fundus that develops retinal edema, tortuous vessels, or hemorrhage requires immediate treatment intensification.

Progressive azotaemia represents a second major failure mode. Hypertension and chronic kidney disease interact bidirectionally, and uncontrolled pressure accelerates renal injury Jepson, feline systemic hypertension classification and pathogenesis. Serial measurement of creatinine, symmetric dimethylarginine, and urine protein-to-creatinine ratio at each monitoring visit identifies declining function before clinical signs appear. A rising creatinine in a cat with controlled blood pressure should prompt investigation of the kidney disease itself instead of automatic dose reduction of antihypertensive medication.

Hypotension from overtreatment is less common but clinically important, particularly in cats with concurrent azotaemia. Lethargy, weakness, ataxia, or apparent worsening of renal values should trigger a blood pressure check instead of empirical dose adjustment. The target range for treated cats is generally accepted as 120 to 160 mmHg systolic, with values below 110 mmHg warranting dose reduction and recheck within days Stepien, feline systemic hypertension diagnosis and management.

Common Clinical Errors and Corrections

The most frequent error is treating a single high blood pressure reading obtained from an anxious cat. Stress-induced elevations are common in feline practice, and a diagnosis of hypertension should rest on multiple consistent measurements using the technique described earlier in this article. A cat that reads 180 mmHg on first presentation but 150 mmHg after acclimatisation in a quiet room does not require antihypertensive therapy.

A second error is failing to recheck blood pressure after initiating treatment. Some clinicians prescribe amlodipine and assume a response without confirmatory measurement. The evidence base shows that a meaningful proportion of cats do not reach target on initial dosing, and dose titration requires objective data Elliott et al., feline hypertension clinical findings and response to antihypertensive treatment. Schedule the first recheck within 7 to 14 days of starting therapy or changing dose.

A third error is neglecting the renin-angiotensin-aldosterone system in hypertensive cats. Hypertensive cats demonstrate significantly increased plasma aldosterone concentrations with decreased plasma renin activity, and the clinical relevance of this pattern remains under investigation Jepson, Syme, Elliott, plasma renin activity and aldosterone concentrations in hypertensive cats. In cats with proteinuria or chronic kidney disease, adding an angiotensin receptor blocker such as telmisartan may be appropriate even when amlodipine controls pressure, although the evidence base for combination therapy is still developing.

Troubleshooting Table

Evidence Limitations and Referral Criteria

The evidence base for feline hypertension management has important gaps. Comparative trials of amlodipine versus telmisartan are limited, although telmisartan has demonstrated clinically relevant blood pressure reduction in a randomised placebo-controlled trial Coleman et al., safety and efficacy of orally administered telmisartan for feline systemic hypertension. The optimal target blood pressure for cats with concurrent kidney disease remains debated, and expert consensus statements provide the most current guidance ACVIM consensus statements. Long-term outcome data comparing different treatment strategies are sparse, and the role of aldosterone in driving hypertension independent of renin activity is not fully resolved Jepson, Syme, Elliott, plasma renin activity and aldosterone concentrations in hypertensive cats.

Referral to a veterinary ophthalmologist is warranted for cats with active retinal detachment, hyphaema, or progressive choroidopathy despite blood pressure control. A veterinary internal medicine specialist should be consulted when hypertension persists despite sequential use of two antihypertensive agents, when azotaemia progresses rapidly, or when hyperthyroidism and hypertension coexist and management of one condition destabilises the other. Diagnostic laboratory involvement is appropriate for aldosterone-to-renin ratio measurement in cats with suspected hyperaldosteronism, particularly those with unexplained hypokalemia or adrenal mass lesions. Regulatory reporting is not generally required for feline hypertension, but clinicians should follow their local professional guidance on adverse drug event reporting where applicable AVMA practice resources.

Frequently Asked Questions

How Should I Manage Blood Pressure Measurement When a Cat Is Too Stressed for Reliable Readings?

Stress-induced elevations are common and can mimic true hypertension. If readings remain high despite a quiet room, minimal restraint, and acclimation time, stop the session and reschedule. Document the values as potentially stress-affected and note the cat's demeanour. In persistently fractious cats, consider a short course of anxiolytic medication before recheck, or measure at home if the owner can be trained. Funduscopic examination for hypertensive retinopathy can support the diagnosis when pressure readings are unreliable. Cats with retinal lesions and high readings warrant treatment even if stress is suspected, because the risk of blindness outweighs the risk of unnecessary therapy. Recheck pressure within one to two weeks once treatment is initiated.

What Should I Do When a Doppler Device Is Unavailable and Only Oscillometric Equipment Exists?

Oscillometric devices tend to underestimate systolic pressure in cats, particularly at higher pressures, and are more sensitive to motion artefact. Use the oscillometric device with a cuff width of 30 to 40 per cent of limb circumference, position the cat quietly, and take five to seven consecutive readings, discarding the highest and lowest values. Compare the average against the same reference ranges used for Doppler, but interpret borderline elevations cautiously. If the oscillometric reading is consistently above 160 mmHg and clinical signs such as retinopathy are present, treatment is justified. When equipment is shared or borrowed, verify calibration against a Doppler device in a stable patient before relying on absolute values for treatment decisions.

How Do I Explain the Need for Lifelong Treatment and Monitoring to a Reluctant Owner?

Frame hypertension as a silent disease that damages the eyes, kidneys, and heart before clinical signs appear. Explain that blindness from retinal detachment is often the first noticeable sign and is frequently irreversible. Emphasize that daily medication is simple, inexpensive, and well tolerated in most cats, and that regular rechecks every two to three months are needed to adjust dosing. Use the owner's own observations, such as increased drinking or subtle vision changes, to make the condition tangible. Offer a written monitoring schedule and explain that stopping treatment abruptly can allow pressure to rebound. Reassure the owner that most cats tolerate amlodipine without noticeable side effects, which improves compliance over the long term.

What Are the Practical Cost Considerations for Long-Term Antihypertensive Therapy in Cats?

Amlodipine is generally low cost and widely available as a human generic formulation, making it the most economical first-line choice. Telmisartan is more expensive but offers an alternative when amlodipine is ineffective or poorly tolerated. Monitoring costs, including blood pressure measurement, biochemistry panels, and urinalysis, typically exceed drug costs over time. A recheck every two to three months with a focused examination and blood pressure measurement is the minimum standard, with annual full laboratory evaluation recommended. For owners with financial constraints, prioritize blood pressure measurement and funduscopy over repeated laboratory testing, and use the lowest effective dose to reduce compounding costs. Discuss these trade-offs openly so the owner can plan for the financial commitment of a chronic disease.

How Does Management of Systemic Hypertension Differ Between Cats and Dogs?

Cats are more likely to have primary or renal-associated hypertension, whereas dogs more often develop hypertension secondary to chronic kidney disease, hyperadrenocorticism, or diabetes mellitus. Amlodipine is the first-line agent in cats, while dogs frequently require combination therapy with an ACE inhibitor or angiotensin receptor blocker earlier in the treatment course. Target systolic pressure is similar, but cats are more prone to stress-induced elevations during measurement, making interpretation more challenging. Cats also develop hypertensive retinopathy with retinal detachment more readily than dogs, so funduscopic examination carries greater diagnostic weight in feline patients. Routine screening is recommended in all cats over nine years of age, while dogs are screened based on underlying disease status instead of age alone.

What Records Should I Maintain for a Hypertensive Cat on Long-Term Therapy?

Maintain a dedicated flow sheet for each hypertensive cat that includes the date, blood pressure readings from each limb and position, cuff size, device used, and the cat's demeanour during measurement. Record the current drug, dose, and frequency, along with any dose adjustments and the reason for each change. Document funduscopic findings at each recheck, including the presence or absence of retinal detachment, hemorrhage, or edema. Laboratory results, including renal values, electrolytes, and urinalysis, should be logged chronologically to track progression of concurrent kidney disease. Note owner-reported observations such as appetite, activity, and vision changes. This record supports dose adjustments, identifies trends before clinical decompensation, and provides continuity when another clinician assumes care.

Related Clinical & Scientific Guides

• Feline Hepatic Lipidosis: Nutritional and Medical Management
• Canine Respiratory Infection: Diagnostic Approach and Treatment
• Canine Respiratory Virus: Diagnostic and Management Considerations

References and Further Reading

• Feline hypertension: clinical findings and response to antihypertensive treatment in 30 cases.. 2001.
• Plasma renin activity and aldosterone concentrations in hypertensive cats with and without azotemia and in response to treatment with amlodipine besylate.. 2014.
• Feline systemic hypertension: Classification and pathogenesis.. 2011.
• Feline systemic hypertension: Diagnosis and management.. 2011.
• Systemic hypertensive disease and the feline fundus.. 2001.
• Safety and efficacy of orally administered telmisartan for the treatment of systemic hypertension in cats: Results of a double-blind, placebo-controlled, randomized clinical trial.. 2019.
• ACVIM Consensus Statements. Journal of Veterinary Internal Medicine.
• MSD Veterinary Manual, Professional Edition. MSD Veterinary Manual.
• American Veterinary Medical Association Practice Resources. American Veterinary Medical Association.

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• Canine Systemic Hypertension: Diagnosis and Therapeutic Monitoring
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• Feline Hepatic Lipidosis: Nutritional and Medical Management

This article is educational professional reference material for veterinary audiences. It is not a substitute for veterinary diagnosis, individual clinical judgment, current product labeling, or applicable regulatory requirements.