Pimozide
Contraindicated
Database
CYP3A4 inhibition
Contraindicated
Source: Kimi deep-research + Cla
Drug reference
Letermovir
Cytomegalovirus terminase complex inhibitor (antiviral) · CMV prophylaxis
START
480 mg PO/IV once daily through day 100 post-HSCT
TYPICAL MAX
480 mg/day (240 mg/day if on cyclosporine)
STOP IF
Severe hypersensitivity
WATCH
Drug interactions (CYP3A4); LFTs if symptoms; CMV viral load
CDSCO approvedATC J05AX18
KDIGO 2024 + manufacturer label
- ONSET
- 1h · absorption
- PEAK
- 2.5h · Tmax
- t½
- 12h · t½
- DURATION
- 1d · once-daily
EXCRETION
Mainly faecal; <2% renal
route + CYP
INTERACTIONS
12 major
incl. contraindicated
PREGNANCY
Use only if benefit outweighs risk; limited data.
FDA category + note
Top interactionssee all 12 →
- PimozideContraindicatedDatabaseKimi deep-research + Cla
- SimvastatinContraindicatedDatabaseKimi deep-research + Cla
- AcalabrutinibSevereDatabaseDDInter
- AlfentanilSevereDatabaseDDInter
Mechanism
Inhibits the CMV DNA terminase complex (pUL51/pUL56/pUL89), preventing viral DNA cleavage and packaging; selective for CMV (no activity against other herpesviruses, no nephro/marrow toxicity of older agents).
Indications
Prophylaxis of CMV infection/disease in adult CMV-seropositive recipients of allogeneic haematopoietic stem-cell transplantProphylaxis of CMV in selected solid-organ transplant recipients
Dosing
- Adult
- 480 mg PO/IV once daily through day 100 post-transplant (with cyclosporine: reduce to 240 mg once daily).
- Pediatric
- Limited data; specialist.
- Renal adjustment
- No dose adjustment for any eGFR (oral). IV: avoid CrCl <10 due to vehicle accumulation.
- Hepatic adjustment
- Moderate impairment: no adjustment; severe: avoid (limited data).
- Geriatric
- No specific adjustment.
- Max dose
- 480 mg once daily (240 mg with cyclosporine)
Pharmacokinetics
Onset
Antiviral effect within days
Peak effect
~1.5–3 h (Tmax)
Duration
~24 h (once-daily)
Half-life
~12 h
Bioavailability
~94% (with cyclosporine ~85%; tablet)
Protein binding
>99%
Metabolism
Mainly biliary excretion; minor UGT1A1/1A3 glucuronidation; CYP3A4 inhibitor/inducer
Excretion
Mainly faecal; <2% renal
Contraindications
- Co-administration with pimozide / ergot alkaloids (CYP3A4 inhibition)
- Co-administration with pitavastatin/simvastatin if also on cyclosporine
- Hypersensitivity
Side effects
Common
Nausea/vomitingDiarrhoeaHeadacheCoughPeripheral oedemaFatigue
Serious
- Hypersensitivity
- Significant drug interactions (CYP3A4/UGT modulation)
Pregnancy & lactation
Pregnancy
Use only if benefit outweighs risk; limited data.
Lactation
Limited data; weigh benefit/risk.
Drug interactions
Simvastatin
Contraindicated
Database
Marked OATP1B/CYP3A4 inhibition
Contraindicated in that combination
Source: Kimi deep-research + Cla
Acalabrutinib
Severe
Database
Drug interaction classified as: metabolism
Source: DDInter
Alfentanil
Severe
Database
Drug interaction classified as: metabolism
Source: DDInter
Atorvastatin
Severe
Database
Drug interaction classified as: metabolism
Source: DDInter
Avanafil
Severe
Database
Drug interaction classified as: metabolism
Source: DDInter
Avapritinib
Severe
Database
Drug interaction classified as: metabolism
Source: DDInter
Benzhydrocodone
Severe
Database
Drug interaction classified as: metabolism
Source: DDInter
Berotralstat
Severe
Database
Drug interaction classified as: excretion
Source: DDInter
Bosutinib
Severe
Database
Drug interaction classified as: metabolism
Source: DDInter
Brexpiprazole
Severe
Database
Drug interaction classified as: metabolism
Source: DDInter
Brigatinib
Severe
Database
Drug interaction classified as: metabolism
Source: DDInter
Related guidelines
Ask House about Letermovir
Continue into a citation-backed clinical answer with the drug context already attached.
Sources: Goodman & Gilman 14e, Katzung, BNF·Verified: 2026-05-20 · House clinical team·Cockpit curated: 2026-05-20