Treatment algorithm

Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups: see disclaimer

INITIAL

hypertensive crisis

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antihypertensive therapy

May be a presenting feature or an intraoperative complication if the patient has not received adequate preoperative medical therapy.

A hypertensive crisis may be precipitated by drugs that inhibit catecholamine uptake, such as tricyclic antidepressants and cocaine; opiates; anesthesia induction; and radiographic contrast media. Possible consequences of a hypertensive crisis include cerebral hemorrhage, cardiac arrhythmias, myocardial infarction, encephalopathy, and heart failure.[84]

Treatment includes immediate alpha blockade with an alpha-1 blocker (e.g., terazosin, doxazosin, or prazosin) or with the nonselective alpha-blocker, phenoxybenzamine. Intravenous agents (nitroprusside, phentolamine, or nicardipine) are short-acting and titratable, and can be used first line.[65] Nitroprusside, phentolamine, or nicardipine can be added, as required, to an oral alpha-1 blocker prescribed in the initial management of hypertensive crisis.[48]

Clinical presentation will inform prescribing decisions. Consult a specialist when deciding on the most appropriate regimen.

Primary options

terazosin: 1 mg orally once daily at bedtime, increase gradually according to response, maximum 20 mg/day in 1-2 divided doses

or

doxazosin: 1 mg orally (immediate-release) once daily at bedtime, increase gradually according to response, maximum 16 mg/day

or

prazosin: 1 mg orally two to three times daily, increase gradually according to response, maximum 20 mg/day

or

phenoxybenzamine: 10 mg orally twice daily initially, increase gradually according to response, maximum 120 mg/day in 2-3 divided doses

-- AND / OR --

nitroprusside: 0.3 to 0.5 micrograms/kg/minute intravenous infusion initially, increase by 0.5 micrograms/kg/minute every 5 minutes according to response, maximum 10 micrograms/kg/minute

More

or

phentolamine: 5 mg intravenously every 10 minutes when required according to response

or

nicardipine: 5 mg/hour intravenous infusion initially, increase by 2.5 mg/hour every 5-15 minutes according to response, maximum 15 mg/hour

ACUTE

without hypertensive crisis

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alpha-blocker

The first step in medical management is to block the effects of catecholamine excess by controlling hypertension and expanding intravascular volume.[1] This is achieved by first establishing adequate alpha blockade.[48]

Alpha-1 blockers (e.g., terazosin, doxazosin, or prazosin), or the nonselective alpha-blocker phenoxybenzamine, are recommended for initial pretreatment blockade.[48][49] These drugs lower blood pressure (BP) by decreasing peripheral vascular resistance.[66]

A major disadvantage of phenoxybenzamine is that it blocks presynaptic alpha-2 receptors enhancing the release of norepinephrine (noradrenaline), resulting in a reflex tachycardia.

Alpha-1 blockers have a shorter duration of action than phenoxybenzamine, making them particularly useful in the perioperative period. The dose of alpha-1 blocker can be rapidly titrated, avoiding postoperative hypotension. These drugs do not enhance the release of norepinephrine and therefore do not cause a reflex tachycardia.

Primary options

terazosin: 1 mg orally once daily at bedtime, increase gradually according to response, maximum 20 mg/day in 1-2 divided doses

OR

doxazosin: 1 mg orally once daily at bedtime, increase gradually according to response, maximum 16 mg/day

OR

prazosin: 1 mg orally two to three times daily, increase gradually according to response, maximum 20 mg/day

OR

phenoxybenzamine: 10 mg orally twice daily initially, increase gradually according to response, maximum 120 mg/day in 2-3 divided doses

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beta-blocker (after alpha blockade)

Treatment recommended for ALL patients in selected patient group

Following adequate alpha blockade, which may take 3-4 days of therapy, beta blockade can be added to manage tachycardia.[3][28][48][69]

The commonly employed agents are beta-1 selective agents such as atenolol and metoprolol.

Beta-blockers must only be used after adequate alpha blockade is achieved preoperatively, as they can cause unopposed stimulation of alpha receptors leading to vasoconstriction and a possible hypertensive crisis.

Adverse effects include bradycardia, bronchospasm, hypotension, and vasoconstriction; therefore, caution is needed when commencing patients with asthma, cardiomyopathies (this is particularly important as cardiomyopathy is a complication of prolonged catecholamine exposure), heart failure, or atrioventricular (AV) conduction abnormalities on beta-blockers.

Primary options

atenolol: 25-100 mg orally once daily

OR

metoprolol tartrate: 50 mg orally (immediate-release) twice daily initially, increase according to response, maximum 450 mg/day

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hydration and high-salt diet (>5 g per day)

Treatment recommended for ALL patients in selected patient group

Hydration and a high-salt diet (>5 g/day) are given for 7-14 days (or until the patient is stable) to offset the effects of catecholamine-induced volume contraction associated with alpha blockade.[48]

All patients should be volume expanded with isotonic saline. In surgical patients, postoperative hypotension may be avoided by adequate intravenous fluid replacement preoperatively.

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Consider – 

calcium-channel blocker or metyrosine

Treatment recommended for SOME patients in selected patient group

Dihydropyridine calcium-channel blockers can supplement alpha blockade if additional BP control is required.[48]

Monotherapy with dihydropyridine calcium-channel blockers is not recommended, but may be an option if the patient is unable to tolerate alpha blockade.[48] Nifedipine and amlodipine are commonly recommended calcium-channel blockers in the setting of perioperative pheochromocytoma BP control.

Calcium-channel blockers lower BP by relaxing smooth muscle in peripheral arteries. This is achieved by inhibition of the norepinephrine-mediated release of intracellular calcium in vascular smooth muscle.

They do not cause orthostatic hypertension and, therefore, have a role in patients with episodic hypertension.

Metyrosine can be used in conjunction with alpha blockade to stabilize BP.[48] Metyrosine, an inhibitor of tyrosine hydroxylase, inhibits catecholamine synthesis. In patients with pheochromocytomas, metyrosine can reduce the biosynthesis of catecholamines by 35% to 80%.[67] This is particularly useful in patients with very high circulating levels of catecholamines, which can be cytotoxic to myocardial cells.

Metyrosine should be started 2 weeks prior to surgery. It can also be used when surgery is contraindicated.

Adverse effects of metyrosine often limit the use of this drug and include crystalluria, fatigue, diarrhea, depression, nightmares, and extrapyramidal signs.[85]

Patients should be instructed on maintaining an adequate fluid intake in order to avoid metyrosine crystalluria.

Primary options

nifedipine: 30-60 mg orally (extended-release) once daily initially, increase gradually according to response, maximum 120 mg/day

OR

amlodipine: 5-10 mg orally once daily

Secondary options

metyrosine: 250 mg orally four times daily initially, increase by 250-500 mg/day increments according to response, maximum 4000 mg/day

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surgical excision of tumor

Treatment recommended for ALL patients in selected patient group

Surgical excision of the entire adrenal gland remains the mainstay of treatment for benign and malignant pheochromocytoma.[48] If appropriate, minimally invasive resection of the tumor is preferred.[48][49]

The American Association of Endocrine Surgeons (AAES) recommends laparoscopic transabdominal or posterior retroperitoneal adrenalectomy.[70] The North American Neuroendocrine Tumor Society (NANETS) recommends open resection if there is evidence of local invasion, malignancy, or recurrence.[49] Minimally invasive adrenalectomy appears to be safe in patients with malignant pheochromocytoma tumor size <6 cm.[71]

Cortical-sparing adrenalectomy should be considered in patients with bilateral pheochromocytoma (recommended by the AAES and NANETS) and familial pheochromocytoma (recommended by NANETS).[49][70] This method can avoid the need for lifelong corticosteroid therapy; however, patients need to be monitored postoperatively for local recurrence.[70]

Paragangliomas are extra-adrenal tumors. They require specialized surgical approaches depending on the various locations of origin.[72]

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continued medical treatment

Treatment recommended for ALL patients in selected patient group

Patients with benign tumors who are unable to undergo surgery - for example, due to a high surgical risk because of heart failure - should receive long-term blood pressure control using alpha blockade, as well as calcium-channel blockers or beta blockade if needed.[48]

Metyrosine is a less-preferred option for controlling hypertension.

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Consider – 

iobenguane I-131

Treatment recommended for SOME patients in selected patient group

Iobenguane I-131 (also known as I-131 metaiodobenzylguanidine [MIBG]) may be considered in patients with an unresectable secreting tumor if I-123 MIBG scintigraphy was positive.[48]

See local specialist protocol for dosing guidelines.

Primary options

iobenguane I 131

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continued medical treatment

Treatment recommended for ALL patients in selected patient group

Continued alpha blockade, with calcium-channel blockers or beta blockade if needed, facilitates blood pressure control in patients with unresectable secreting tumors.[48][49]

Adjustments to the blood pressure treatment regimen may be required should additional therapy be prescribed.[48]

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Consider – 

radiation therapy ± cytoreductive resection

Treatment recommended for SOME patients in selected patient group

Radiation therapy with or without cytoreductive resection is a treatment option for patients with locally unresectable disease.[28][48][49]

Risks, benefits, and alternatives to surgery should be considered.[28]

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Consider – 

postsurgical chemotherapy

Treatment recommended for SOME patients in selected patient group

Chemotherapy is given to some patients with metastatic disease after surgery.

Chemotherapy regimens usually comprise cyclophosphamide plus vincristine plus dacarbazine (CVD), or temozolomide.[48][73]

Temozolomide, an alkylating drug and an alternative to dacarbazine, can be used as monotherapy or in combination with other antineoplastic drugs in patients with malignant pheochromocytomas and SDHB mutations.[74][75]

See local specialist protocol for dosing guidelines.

Primary options

cyclophosphamide

and

vincristine

and

dacarbazine

Secondary options

temozolomide

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Consider – 

iobenguane I-131 or radiation therapy

Treatment recommended for SOME patients in selected patient group

Additional therapy may be required in some patients with residual tumor, such as multifocal or metastatic disease.[86]

The radiopharmaceutical iobenguane I-131 (also known as I-131 metaiodobenzylguanidine [MIBG]) may be considered if I-123 MIBG scintigraphy was positive.[48][49]

External beam radiation therapy provides local tumor control and relief of symptoms at both soft tissue sites of metastases, and painful bone metastases.[76][77]

Primary options

iobenguane I 131

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Consider – 

enrollment in clinical trial

Treatment recommended for SOME patients in selected patient group

Potential enrollment in a clinical trial should be discussed with the patient.

Somatostatin analogs (octreotide, lanreotide) or peptide receptor radionuclide therapy ([PRRT] with lutetium Lu 177 dotatate) can be considered for patients with somatostatin receptor positive disease.[48]

Sunitinib, a tyrosine kinase inhibitor, demonstrated antitumor efficacy in a phase 2 randomized, placebo-controlled trial that included patients with metastatic pheochromocytoma.[78]

Other clinical trial options may include immunotherapy (e.g., pembrolizumab) or hypoxia-inducible factor 2 alpha inhibitors (e.g., belzutifan).[86][87]

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Plus – 

continued medical treatment

Treatment recommended for ALL patients in selected patient group

Continued alpha blockade, with calcium-channel blockers or beta blockade if needed, facilitates blood pressure control in patients with unresectable secreting tumors.[48][49]

Adjustments to the blood pressure treatment regimen may be required should additional therapy be prescribed.[48]

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Consider – 

cytoreductive resection

Treatment recommended for SOME patients in selected patient group

Cytoreductive resection is a treatment option in patients with catecholamine-secreting distant metastases.[48]

Risks, benefits, and alternatives to surgery should be considered.[28]

Back
Consider – 

postsurgical chemotherapy

Treatment recommended for SOME patients in selected patient group

Chemotherapy is given to some patients with metastatic disease after surgery.

Chemotherapy regimens usually comprise cyclophosphamide plus vincristine plus dacarbazine (CVD), or temozolomide.[48][73]

Temozolomide, an alkylating drug and an alternative to dacarbazine, can be used as monotherapy or in combination with other antineoplastic drugs in patients with malignant pheochromocytomas and SDHB mutations.[74][75]

See local specialist protocol for dosing guidelines.

Primary options

cyclophosphamide

and

vincristine

and

dacarbazine

Secondary options

temozolomide

Back
Consider – 

iobenguane I-131, radiation, or ablative therapy

Treatment recommended for SOME patients in selected patient group

Additional therapy may be required in some patients with residual tumor, such as multifocal or metastatic disease.[86]

The radiopharmaceutical iobenguane I-131 (also known as I-131 metaiodobenzylguanidine [MIBG]) may be considered if I-123 MIBG scintigraphy was positive.[48][49] See local specialist protocol for dosing guidelines.

Palliative external beam radiation therapy may be considered for oligometastatic disease or limited metastases of the liver.[48]

Radiofrequency ablation of hepatic and bone metastases may also be effective.[49][79]

Primary options

iobenguane I 131

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Consider – 

enrollment in clinical trial

Treatment recommended for SOME patients in selected patient group

Potential enrollment in a clinical trial should be discussed with the patient.

Somatostatin analogs (octreotide, lanreotide) or peptide receptor radionuclide therapy ([PRRT] with lutetium Lu 177 dotatate) can be considered for patients with somatostatin receptor positive disease.[48]

Sunitinib, a tyrosine kinase inhibitor, demonstrated antitumor efficacy in a phase 2 randomized, placebo-controlled trial that included patients with metastatic pheochromocytoma.[78]

Other clinical trial options may include immunotherapy (e.g., pembrolizumab) or hypoxia-inducible factor 2 alpha inhibitors (e.g., belzutifan).[86][87]

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Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups. See disclaimer

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