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Triazole Antifungal (Aspergillosis / Mucormycosis) Pregnancy: §4.6: 'There are no data from the use of CRESEMBA in pregnant women. Studies in animals have shown reproductive toxicity. The potential risk for humans is unknown. 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.' Women of childbearing potential: '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.' Fertility: 'There are no data on the effect of isavuconazole on human fertility. Studies in animals did not show impairment of fertility in male or female rats.'

Isavuconazole

Brand names: Cresemba

Isavuconazole (administered as the prodrug isavuconazonium sulfate) is a broad-spectrum triazole antifungal used to treat invasive aspergillosis and mucormycosis, available in oral and intravenous forms.

Adult dose

Dose: Invasive fungal infection — this SPC gives ONE regimen for all of its licensed indications; its posology is not stratified by indication, and the licensed indication section was not fetched in this bundle, so the indication list itself was not read here. Adults: LOADING — two 100 mg capsules (200 mg) every 8 hours during Days 1 and 2, six administrations in total (total daily dose during Days 1 and 2 = six 100 mg capsules). MAINTENANCE — two 100 mg capsules (200 mg) once daily, starting 12 to 24 hours after the last loading dose. SCOPE: these figures are from the CRESEMBA 100 mg hard CAPSULE SPC. The intravenous presentation named on this page is a separate product ('powder for concentrate for solution for infusion containing 200 mg isavuconazole') whose own SPC was not fetched, so no infusion instructions are published here.
Route: Oral — 'CRESEMBA capsules can be taken with or without food. CRESEMBA capsules should be swallowed whole. Do not chew, crush, dissolve or open the capsules.' 'All capsules per dose must be taken at the same time.' IV/oral switch, verbatim: 'CRESEMBA is also available as powder for concentrate for solution for infusion containing 200 mg isavuconazole. On the basis of the high oral bioavailability (98%, see section 5.2), switching between intravenous and oral administration is appropriate when clinically indicated.'
Frequency: Every 8 hours for six doses during Days 1 and 2 (loading), then once daily (maintenance), starting 12 to 24 hours after the last loading dose
Max: 200 mg isavuconazole — §4.2, verbatim: 'The maximum of any individual loading or daily maintenance dose to be administered to any patient is 200 mg isavuconazole.'
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.' EARLY 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.' ELDERLY: 'No dose adjustment is necessary for elderly patients; however, the clinical experience in elderly patients is limited.' RENAL: 'No dose adjustment is necessary in adult patients with renal impairment, including patients with end-stage renal disease.' 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.' STRONG CYP3A4 INHIBITORS: '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' (a two-fold exposure increase was seen with lopinavir/ritonavir). ⚠️ QT SHORTENING, not prolongation — §4.4: isavuconazole 'shortened the QTc interval in a concentration-related manner'; it is contraindicated in familial short QT syndrome, and 'Caution is warranted when prescribing isavuconazole to patients taking other medicinal products known to decrease the QT interval, such as rufinamide.' ⚠️ §4.4 and §4.8 are both marked truncated at the source-fetch limit in this bundle, so the interaction and adverse-reaction material below is incomplete; §4.2 posology is complete for the capsule presentation.

Paediatric dose

Route: Oral — capsules swallowed whole, with or without food; all capsules per dose taken at the same time. 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' (that IV product's SPC was not fetched).
Frequency: Loading: every 8 hours during Days 1 and 2, six administrations in total. Maintenance: once daily, starting 12 to 24 hours after the last loading dose.
dosePerKg is null deliberately: the SPC's paediatric regimen is WEIGHT-BANDED in whole capsules, not a per-kilogram figure, so no weight calculator is offered — reading a band as a mg/kg value would misdose. VERBATIM §4.2 Table 2, 'Recommended Dosage for CRESEMBA in paediatric patients aged from 6 years to less than 18 years' (columns: 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 — 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.' Footnotes: loading is 'Six administrations in total'; maintenance starts '12 to 24 hours after the last loading dose'. The same ceiling applies as in adults: 'The maximum of any individual loading or daily maintenance dose to be administered to any patient is 200 mg isavuconazole.' AGE AND FORMULATION LIMITS, verbatim: 'Paediatric patients from one year to below 6 years of age, or with a bodyweight less than 16 kg, or are not able to swallow CRESEMBA hard capsules may receive CRESEMBA as intravenous infusion. The use of CRESEMBA 100 mg capsules has not been studied in paediatric patients. The safety and efficacy of CRESEMBA in paediatric patients aged less than 1 year has not been established.' §4.4 adds: 'Paediatric patients from 6 years to less than 18 years of age and with a bodyweight at least 32 kg may receive CRESEMBA 100 mg capsules. However, the use of CRESEMBA 100 mg capsules has not been studied in paediatric patients.' ORGAN IMPAIRMENT: 'No dose recommendation can be made for paediatric patients with renal impairment' and likewise none for hepatic impairment, 'as no relevant data are available'. Verify any under-18 dose against a children's formulary and specialist infection advice before prescribing. (No ageRanges are published: the SPC's bands are by WEIGHT, not age, and the age-band renderer would misrepresent them as five alternative doses for one age range.)

Dose adjustments

Renal

§4.2: 'No dose adjustment is necessary in adult patients with renal impairment, including patients with end-stage renal disease (see section 5.2). No dose recommendation can be made for paediatric patients with renal impairment, as no relevant data are available.'

Hepatic

§4.2: '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 patients with hepatic impairment, as no relevant data are available.' §4.4 adds that such patients 'should be carefully monitored for potential drug toxicity'.

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

  • §4.3: 'Hypersensitivity to the active substance or to any of the excipients listed in section 6.1.'
  • §4.3: co-administration with ketoconazole
  • §4.3: co-administration with high-dose ritonavir (>200 mg every 12 hours)
  • §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
  • §4.3: 'Patients with familial short QT syndrome' — isavuconazole SHORTENS the QTc interval

Side effects

  • Most common treatment-related reactions in adults (§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%)'
  • Most often led to permanent discontinuation (§4.8): '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%)'
  • 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 (§4.8 Table 4)
  • Uncommon: neutropenia, thrombocytopenia, pancytopenia, leukopenia, anaemia; hypersensitivity; convulsion, syncope, encephalopathy, peripheral neuropathy; atrial fibrillation, tachycardia, bradycardia, QT shortened on ECG; circulatory collapse, hypotension; bronchospasm; hepatitis; drug eruption; peripheral oedema (§4.8 Table 4)
  • Not known: anaphylactic reaction (§4.8)
  • Severe cutaneous adverse reactions — §4.4: 'Severe cutaneous adverse reactions, such as Stevens-Johnson syndrome, have been reported during treatment with azole antifungal agents. If a patient develops a severe cutaneous adverse reaction, CRESEMBA should be discontinued.'
  • Hypersensitivity — §4.4: reactions 'include: anaphylactic reaction, hypotension, respiratory failure, dyspnoea, drug eruption, pruritus, and rash... In case of anaphylactic reaction, isavuconazole should be discontinued immediately'; caution in patients hypersensitive to other azole antifungals
  • This side-effect list may be incomplete — check the full SPC.

Interactions

  • Contraindicated combinations (§4.3): ketoconazole; high-dose ritonavir (>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)
  • Strong CYP3A4/5 inhibitors (§4.4): 'For the strong CYP3A4 inhibitor lopinavir/ritonavir, a two-fold increase in isavuconazole exposure was observed. For other strong CYP3A4/5 inhibitors, a less pronounced effect can be expected. No dose adjustment of isavuconazole is necessary... however caution is advised as adverse drug reactions may increase.'
  • QT-shortening medicines (§4.4): 'Caution is warranted when prescribing isavuconazole to patients taking other medicinal products known to decrease the QT interval, such as rufinamide.'
  • ⚠️ §4.4 is truncated at the source-fetch limit immediately after the CYP3A4/5 inhibitor paragraph, and §4.5 was not fetched — the interaction list above is NOT complete. Check the full SPC §4.5 before prescribing.

Monitoring

  • Hepatic enzymes — §4.4: 'Elevated liver transaminases have been reported in clinical studies... Monitoring of hepatic enzymes should be considered, as clinically indicated. Hepatitis has been reported with azole antifungal agents including isavuconazole.'
  • Patients with severe hepatic impairment (Child-Pugh C) 'should be carefully monitored for potential drug toxicity' if treated at all (§4.4)
  • Clinical response, which determines the duration of therapy; for treatment beyond 6 months 'the benefit-risk balance should be carefully considered' (§4.2)
  • Watch for severe cutaneous reactions and hypersensitivity, and discontinue if they occur (§4.4)

Clinical monograph

How it works

It inhibits fungal cytochrome P450 lanosterol 14-alpha-demethylase, blocking ergosterol biosynthesis and compromising the fungal cell membrane.

Prescribing in practice

  • Unlike most azoles isavuconazole shortens the QT interval and is contraindicated in familial short QT syndrome, while remaining a clinically significant CYP3A4 interacting drug.
  • It is contraindicated with strong CYP3A4 inducers or inhibitors such as rifampicin and high-dose ritonavir, which alter exposure substantially.
  • It requires caution and monitoring in hepatic impairment, where it has not been studied in severe disease.

Monitoring

Monitor liver function during therapy and review concurrent medicines for CYP3A4 interactions; routine therapeutic drug monitoring is less commonly required than with some other triazoles.

Counselling the patient

  • Tell your prescriber about all other medicines, as isavuconazole has important drug interactions.
  • Report signs of liver problems such as jaundice, dark urine or persistent nausea.
  • Mention any family history of a short QT heart rhythm condition.

Evidence & guidelines

Isavuconazole is recommended in specialist antifungal guidance as a treatment option for invasive aspergillosis and mucormycosis, supported by its registration trials.

Reference: Maertens et al. Lancet 2016 (SECURE); Marty et al. Lancet Infect Dis 2016 (VITAL — mucormycosis); ESCMID/ECMM Mucormycosis Guidelines 2019; MHRA SPC Cresemba; 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.

Pathways