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Triazole antifungal Pregnancy: UK SPC section 4.6: 'There are no data from the use of CRESEMBA in pregnant women. Studies in animals have shown reproductive toxicity... CRESEMBA must not be used during pregnancy except in patients with severe or potentially life-threatening fungal infections, in whom isavuconazole may be used if the anticipated benefits outweigh the possible risks to the foetus.' 'CRESEMBA is not recommended for women of childbearing potential who are not using contraception.' Breast-feeding: 'A risk to newborns and infants cannot be excluded. Breast-feeding should be discontinued during treatment with CRESEMBA.'

Isavuconazole

Brand names: Cresemba

Isavuconazole is a broad-spectrum triazole antifungal (administered as the prodrug isavuconazonium) used for invasive aspergillosis and invasive mucormycosis.

Adult dose

Dose: Treatment of invasive fungal infection in adults — LOADING: 200 mg (two 100 mg capsules) every 8 hours during Days 1 and 2, six administrations in total; then MAINTENANCE: 200 mg (two 100 mg capsules) once daily, starting 12 to 24 hours after the last loading dose. SCOPE: this is the ORAL capsule regimen only, taken from the CRESEMBA 100 mg hard capsule SPC. The intravenous form (CRESEMBA 200 mg powder for concentrate for solution for infusion) is a separate product whose own SPC was not fetched in this bundle; the fetched SPC states that 'on the basis of the high oral bioavailability (98%...), switching between intravenous and oral administration is appropriate when clinically indicated'.
Route: Oral. Capsules can be taken with or without food and should be swallowed whole — 'Do not chew, crush, dissolve or open the capsules.' All capsules making up a single dose must be taken at the same time.
Frequency: Loading phase: every 8 hours during Days 1 and 2 (six doses in total). Maintenance phase: once daily, beginning 12 to 24 hours after the last loading dose.
Max: Maximum 200 mg isavuconazole for any individual loading dose or for the daily maintenance dose — SPC §4.2: 'The maximum of any individual loading or daily maintenance dose to be administered to any patient is 200 mg isavuconazole.'
Verbatim source wording (UK SPC section 4.2, Table 1 'Recommended dosage for CRESEMBA in adult patients'): loading dose 'every 8 hours during Days 1 and 2' = 'Two 100 mg capsules', with the 'total daily dose during Days 1 and 2' = 'Six 100 mg capsules'; maintenance dose (once daily) = 'Two 100 mg capsules'. Footnotes: '1 Six administrations in total. 2 Starting 12 to 24 hours after the last loading dose.' TIMING OF THERAPY: 'Early targeted therapy (pre-emptive or diagnostic-driven therapy) may be instituted pending confirmation of the disease from specific diagnostic tests. However, once these results become available, antifungal therapy should be adjusted accordingly.' DURATION: 'Duration of therapy should be determined by the clinical response... For long-term treatment beyond 6 months, the benefit-risk balance should be carefully considered.' ELDERLY: 'No dose adjustment is necessary for elderly patients; however, the clinical experience in elderly patients is limited.' ⚠️ This bundle contains ONLY the UK SPC — the openFDA and WHO providers are null. ⚠️ Sections 4.4 and 4.8 are marked truncated at the source-fetch limit and section 4.5 (interactions) was not retrieved at all, so the interaction list below is only what appears in sections 4.3 and 4.4 and must not be read as complete.

Paediatric dose

Route: Oral capsules, swallowed whole; all capsules per dose taken at the same time
Frequency: Loading dose every 8 hours during Days 1 and 2 (six administrations in total), then maintenance once daily starting 12 to 24 hours after the last loading dose
Max: Maximum 200 mg isavuconazole for any individual loading dose or for the daily maintenance dose (the SPC applies this ceiling to 'any patient')
The SPC doses children by WEIGHT BAND, not by mg/kg, so no per-kg figure exists and none has been invented. Verbatim source wording (UK SPC section 4.2, Table 2 'Recommended Dosage for CRESEMBA in paediatric patients aged from 6 years to less than 18 years'), given as loading dose every 8 hours during Days 1 and 2 / total daily dose during Days 1 and 2 / maintenance dose once daily: 16 kg to <18 kg — 'Two 40 mg capsules' / 'Six 40 mg capsules' / 'Two 40 mg capsules'; 18 kg to <25 kg — 'Three 40 mg capsules' / 'Nine 40 mg capsules' / 'Three 40 mg capsules'; 25 kg to <32 kg — 'Four 40 mg capsules' / 'Twelve 40 mg capsules' / 'Four 40 mg capsules'; 32 kg to <37 kg — 'One 100 mg capsule and two 40 mg capsules' / 'Three 100 mg capsules and six 40 mg capsules' / 'One 100 mg capsule and two 40 mg capsules'; 37 kg and above — 'Five 40 mg capsules or two 100 mg capsules' / 'Fifteen 40 mg capsules or six 100 mg capsules' / 'Five 40 mg capsules or two 100 mg capsules'. ⚠️ The 40 mg capsule is a DIFFERENT product from the 100 mg capsule sourced here; only the 32 kg and above bands can be made up from 100 mg capsules, and section 4.4 warns 'the use of CRESEMBA 100 mg capsules has not been studied in paediatric patients'. Children from 1 year to below 6 years, or weighing less than 16 kg, or unable to swallow capsules 'may receive CRESEMBA as intravenous infusion'. 'The safety and efficacy of CRESEMBA in paediatric patients aged less than 1 year has not been established.' No dose recommendation can be made for paediatric renal or hepatic impairment. Verify against a children's formulary before use.

Dose adjustments

Renal

'No dose adjustment is necessary in adult patients with renal impairment, including patients with end-stage renal disease.' 'No dose recommendation can be made for paediatric patients with renal impairment, as no relevant data are available.' (UK SPC section 4.2)

Hepatic

'No dose adjustment is necessary in adult patients with mild or moderate hepatic impairment (Child-Pugh Classes A and B).' Isavuconazole 'has not been studied in adult patients with severe hepatic impairment (Child-Pugh Class C). Use in these patients is not recommended unless the potential benefit is considered to outweigh the risks.' No dose recommendation can be made for paediatric hepatic impairment. (UK SPC sections 4.2 and 4.4)

Dose independently re-sourced from UK Summary of Product Characteristics (SPC) via the eMC — clinician-reviewed. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

  • Hypersensitivity to the active substance or to any of the excipients (UK SPC section 4.3)
  • Co-administration with ketoconazole (UK SPC section 4.3)
  • Co-administration with high-dose ritonavir (greater than 200 mg every 12 hours) (UK SPC section 4.3)
  • Co-administration with strong CYP3A4/5 inducers such as rifampicin, rifabutin, carbamazepine, long-acting barbiturates (e.g. phenobarbital), phenytoin and St John's wort, or with moderate CYP3A4/5 inducers such as efavirenz, nafcillin and etravirine (UK SPC section 4.3)
  • Patients with familial short QT syndrome (UK SPC section 4.3)

Side effects

  • Most common treatment-related reactions in adults (section 4.8): elevated liver chemistry tests (7.9%), nausea (7.4%), vomiting (5.5%), dyspnoea (3.2%), abdominal pain (2.7%), diarrhoea (2.7%), injection site reaction (2.2%), headache (2.0%), hypokalaemia (1.7%) and rash (1.7%)
  • Common: hypokalaemia; decreased appetite; delirium; headache; somnolence; thrombophlebitis; dyspnoea; acute respiratory failure; vomiting; diarrhoea; nausea; abdominal pain; elevated liver chemistry tests; rash; pruritus; renal failure; chest pain; fatigue
  • Uncommon: neutropenia, thrombocytopenia, pancytopenia, leukopenia, anaemia; hypersensitivity; hypomagnesaemia, hypoglycaemia, hypoalbuminaemia, hyponatraemia; depression, insomnia; convulsion, syncope, dizziness, paraesthesia, encephalopathy, peripheral neuropathy, dysgeusia; vertigo; atrial fibrillation, tachycardia, bradycardia, palpitations, atrial flutter, electrocardiogram QT shortened, supraventricular tachycardia, ventricular and supraventricular extrasystoles; circulatory collapse, hypotension; bronchospasm, tachypnoea, haemoptysis, epistaxis; dyspepsia, constipation, abdominal distension; hepatomegaly, hepatitis; petechiae, alopecia, drug eruption, dermatitis; back pain; peripheral oedema, malaise, asthenia
  • Not known: anaphylactic reaction
  • Reactions most often leading to permanent discontinuation in adults: confusional state (0.7%), acute renal failure (0.7%), increased blood bilirubin (0.5%), convulsion (0.5%), dyspnoea (0.5%), epilepsy (0.5%), respiratory failure (0.5%) and vomiting (0.5%)
  • Severe cutaneous adverse reactions such as Stevens-Johnson syndrome have been reported with azole antifungals — discontinue if one develops (section 4.4)
  • This side-effect list may be incomplete — check the full SPC.

Interactions

  • Contraindicated: ketoconazole; high-dose ritonavir (greater than 200 mg every 12 hours); strong CYP3A4/5 inducers (rifampicin, rifabutin, carbamazepine, long-acting barbiturates such as phenobarbital, phenytoin, St John's wort); moderate CYP3A4/5 inducers (efavirenz, nafcillin, etravirine) (section 4.3)
  • Strong CYP3A4/5 inhibitors — 'For the strong CYP3A4 inhibitor lopinavir/ritonavir, a two-fold increase in isavuconazole exposure was observed... No dose adjustment of isavuconazole is necessary when co-administered with strong CYP3A4/5 inhibitors, however caution is advised as adverse drug reactions may increase' (section 4.4)
  • Medicines known to decrease the QT interval, such as rufinamide — 'Caution is warranted when prescribing isavuconazole to patients taking other medicinal products known to decrease the QT interval' (section 4.4)
  • This interaction list may be incomplete — check the full SPC.

Monitoring

  • Hepatic enzymes — 'Monitoring of hepatic enzymes should be considered, as clinically indicated'; elevated liver transaminases have been reported and hepatitis has occurred with azole antifungals including isavuconazole (section 4.4)
  • Patients with severe hepatic impairment, if treated at all, 'should be carefully monitored for potential drug toxicity' (section 4.4)
  • Watch for hypersensitivity/anaphylaxis — 'In case of anaphylactic reaction, isavuconazole should be discontinued immediately and appropriate medical treatment should be initiated' (section 4.4)
  • Watch for severe cutaneous reactions — discontinue CRESEMBA if a severe cutaneous adverse reaction develops (section 4.4)
  • QT interval: isavuconazole SHORTENS QTc in a concentration-related manner (LSM difference from placebo 13.1 ms at 2 hours post dose for the 200 mg regimen) and is contraindicated in familial short QT syndrome (sections 4.3 and 4.4)
  • Clinical response, which determines duration of therapy; reconsider the benefit-risk balance for treatment beyond 6 months (section 4.2)

Clinical monograph

How it works

It inhibits fungal cytochrome P450-dependent lanosterol 14-alpha-demethylase, blocking ergosterol synthesis and disrupting the fungal cell membrane.

Prescribing in practice

  • It is contraindicated with strong CYP3A4 inducers (and certain strong inhibitors such as ketoconazole) and in patients with familial short QT syndrome, as isavuconazole shortens the QT interval.
  • It is a substrate and moderate inhibitor of CYP3A4, so review co-medications carefully for interactions.
  • Hepatic adverse effects can occur; assess baseline liver function and use caution in significant hepatic impairment.

Monitoring

Monitor liver function tests at baseline and during treatment, and review concomitant medicines for clinically important interactions.

Counselling the patient

  • Report yellowing of the skin or eyes, dark urine, nausea or abdominal pain promptly.
  • Tell your clinician about all other medicines, as many interact with this antifungal.
  • Complete the full prescribed course to clear the infection.

Evidence & guidelines

Non-inferiority to voriconazole in invasive aspergillosis was shown in the SECURE trial.

Reference: NICE TA487/TA738; SmPC; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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