Inadvertent intra-arterial injection

Devulapalli, 2015Rohm, 2014Sen, 2005

Severe peripheral ischaemia can follow the inadvertent intra-arterial injection of drugs, which may be iatrogenic or by self-injection. People who self-inject drugs may delay seeking treatment and experience poorer outcomes.

The pathophysiological basis for the sudden severe ischaemia probably involves 3 main mechanisms—vasospasm, chemical endarteritis, and drug–particulate embolisation and thrombosis. Data to guide treatment are lacking; however, based on the possible mechanisms, triple therapy with a vasodilator, an oral corticosteroid (to reduce inflammation) and an anticoagulant is suggested.

For vasodilation to relieve ischaemia, the initial dose depends on the patient’s blood pressure. Suitable dosage regimens are:

1glyceryl trinitrate 5 to 15 mg transdermally, once daily. Apply for a maximum of 14 hours in a 24-hour period glyceryl trinitrate glyceryl trinitrate glyceryl trinitrate

OR

2amlodipine 5 to 10 mg orally, daily amlodipine amlodipine amlodipine

OR

2felodipine modified-release 2.5 to 10 mg orally, daily felodipine felodipine felodipine

OR

2nifedipine modified-release 30 to 60 mg orally, daily. nifedipine nifedipine nifedipine

If ischaemia is severe, seek specialist advice on the use of alprostadil.

To reduce inflammation, a suitable dosage regimen is:

dexamethasone 4 mg intravenously, as a single dose dexamethasone dexamethasone dexamethasone

FOLLOWED BY

prednisolone (or prednisone) 50 mg orally, daily for 2 days, then taper dose rapidly over 1 week to stop. prednis ol one prednis(ol)one prednis(ol)one

For anticoagulation, unfractionated heparin (UFH) is usually the first-line option. Dose UFH according to the local protocol for treating venous thromboembolism. If a local protocol is not available, a suitable dosage regimen is:

unfractionated heparin 80 units/kg intravenously as a loading dose, followed by 18 units/kg/hour by intravenous infusion, adjusted according to APTT. unfractionated heparin heparin, unfractionated heparin, unfractionated

Consult a local protocol for activated partial thromboplastin time (APTT) target values or seek specialist haematologist advice. UFH requires intensive laboratory monitoring (see Practical information on using unfractionated heparin for information, including management of bleeding).

An alternative anticoagulant is low molecular weight heparin (LMWH). Suitable dosage regimens areSen, 2005:

1dalteparin (CrCl 30 mL/min or more) 100 units/kg subcutaneously, twice daily dalteparin dalteparin dalteparin

OR

1enoxaparin enoxaparin enoxaparin enoxaparin

CrCl 30 mL/min or more: 1 mg/kg subcutaneously, twice daily

CrCl less than 30 mL/min: 1 mg/kg subcutaneously, once daily.

For dalteparin and enoxaparin, see Practical information on using low molecular weight heparin for further information, including management of bleeding. See also Considerations for anticoagulation in patients with obesity if applicable.