Sildenafil parenteral
- Drugs List
- Therapeutic Indications
- Dosage
- Administration
- Contraindications
- Precautions and Warnings
- Pregnancy and Lactation
- Side Effects
- Monograph
Presentation
Parenteral formulations containing sildenafil (as sildenafil citrate).
Drugs List
Therapeutic Indications
Uses
Pulmonary arterial hypertension: functional grades II and III
For the treatment of patients with pulmonary arterial hypertension (WHO functional class II and III) to improve exercise capacity who are currently prescribed oral sildenafil and who are temporarily unable to take oral medication, but are otherwise clinically and haemodynamically stable.
Dosage
In cases of clinical deterioration in spite of sildenafil treatment, alternative therapies should be considered.
Adults
10mg three times daily, by intravenous bolus injection.
Patients with Renal Impairment
No initial dosage adjustments are required.
If treatment is not tolerated well the dose should be reduced to 10mg twice daily after careful risk/benefit assessment.
Patients with Hepatic Impairment
No initial dosage adjustments are required. If treatment is not tolerated well the dose should be reduced to 10mg twice daily after careful risk/benefit assessment.
Additional Dosage Information
Sildenafil for injection should be administered to patients already prescribed oral sildenafil as a replacement for the oral formulation where the patient is temporarily unable to take the oral therapy. A 10mg dose of sildenafil injection is predicted to provide exposure of sildenafil (and its metabolite) and pharmacological effects comparable to those of a 20mg oral dose.
Administration
For intravenous use as bolus injection.
Contraindications
Children under 18 years
Systolic blood pressure < 90mmHg
Breastfeeding
Hereditary degenerative retinal disorder
History of non-arteritic anterior ischaemic optic neuropathy (NAION)
Recent cerebrovascular accident
Recent myocardial infarction
Severe hepatic impairment
Sickle cell disease
Precautions and Warnings
Predisposition to priapism
Acute peptic ulcer
Anatomical deformation of penis
Autonomic neuropathy
Cardiovascular disorder
Coagulopathy
Dehydration
Hepatic impairment
Hypotension
Left ventricular outflow obstruction
Leukaemia
Multiple myeloma
Pregnancy
Pulmonary hypertension secondary to venous occlusive disorder
Renal impairment
Advise ability to drive/operate machinery may be affected by side effects
Concurrent alpha blockers: only initiate therapy when blood pressure stable
Treatment to be initiated and supervised by a specialist
Advise patient to report any erection lasting more than 4 hours
Cardiovascular events may occur during or shortly after sexual intercourse
Consider veno-occlusive disease if pulmonary oedema occurs
To discontinue, reduce dose gradually
Discontinue if any kind of visual disturbance occurs
Advise patient not to take St John's wort concurrently
Advise patients not to take nitrates or amyl nitrite concurrently
Advise patient grapefruit products may increase plasma level
Female: Ensure adequate contraception during treatment
In cases of clinical deterioration in spite of sildenafil treatment, alternative therapies should be considered.
Severe pulmonary hypertension (functional class IV): Efficacy has not been established.
If the patient's clinical condition deteriorates, therapies used during the severe stage of the disease (e.g. epoprostenol) should be considered.
The risk-benefit ratio has not been established for patients with functional class I pulmonary arterial hypertension.
Only primary pulmonary hypertension and pulmonary hypertension associated with connective tissue disease or congenital heart disease has been studied.
Pregnancy and Lactation
Pregnancy
Use sildenafil with caution in pregnancy.
The manufacturer does not recommend using sildenafil during pregnancy unless strictly necessary. There is limited data available regarding the use of sildenafil in pregnancy. Briggs 2015 states there has been no embryo-foetal harm observed, however the drug should not be withheld because of pregnancy due to the risk of the condition. However, in one trial increased risk of persistent pulmonary hypertension of the newborn and increased mortality have been reported when sildenafil was used for the unlicensed indication of early-onset intrauterine growth restriction (MHRA 2018).
Animal studies do not indicate direct or indirect harmful effects on pregnancy or embryonal development, but have shown toxicity with respect to postnatal development.
Lactation
Sildenafil is contraindicated during breastfeeding.
At the time of writing there are no controlled studies in breastfeeding women. It is not known if sildenafil is excreted into human breast milk. The molecular weight and half life suggest that sildenafil and its active metabolite will be excreted into breast milk, but the high protein binding would limit the amount excreted. Amounts ingested would not be expected to cause any adverse effects.
Side Effects
Abdominal distension
Alopecia
Anaemia
Angina pectoris
Anxiety
Arrhythmias
Back pain
Blurred vision
Bronchitis
Burning sensation
Cardiovascular accident
Cellulitis
Cerebrovascular haemorrhage
Chromatopsia
Cough
Cyanopsia
Diarrhoea
Diplopia
Dizziness
Dry mouth
Dyspepsia
Epistaxis
Erythema
Eye irritation
Fluid retention
Flushing
Gastritis
Gastro-enteritis
Gastroesophageal reflux disease
Gynaecomastia
Haematospermia
Haematuria
Haemorrhoids
Headache
Hypertension
Hypoaesthesia
Hypotension
Influenza
Insomnia
Migraine
Myalgia
Myocardial infarction
Nasal congestion
Night sweats
Non-arteritic anterior ischaemic optic neuropathy (NAION)
Ocular hyperaemia
Oedema
Painful extremities
Palpitations
Paraesthesia
Penile haemorrhage
Photophobia
Priapism
Prolonged erection
Pyrexia
Rash
Reduced visual acuity
Retinal haemorrhage
Retinal vein occlusion
Rhinitis
Seizures
Severe cutaneous adverse reactions
Sinusitis
Sudden cardiac death
Sudden deafness
Syncope
Transient ischaemic attack
Tremor
Vertigo
Visual disturbances
Visual field defects
Overdosage
It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.
The following number will direct the caller to the relevant local centre (0844) 892 0111
Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( www.toxbase.org ) or if this is unavailable at the backup site ( www.toxbasebackup.org ).
Further Information
Last Full Review Date: March 2019
Reference Sources
Drugs During Pregnancy and Lactation: Treatment Options and Risk Assessment, 3rd edition (2015) ed. Schaefer, C., Peters, P. and Miller, R. Elsevier, London.
Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk, 10th edition (2015) ed. Briggs, G., Freeman, R. Wolters Kluwer Health, Philadelphia.
Summary of Product Characteristics: Revatio 0.8mg/ml solution for injection. Pfizer Ltd. Revised July 2018.
MHRA Drug Safety Update November 2018
Available at: https://www.mhra.gov.uk
Last accessed: 05 March 2019.
NICE Evidence Services Available at: www.nice.org.uk Last accessed: 05 March 2019.
Medscape UK | Univadis prescription drug monographs & interactions are based on FDB Multilex Content
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