Heparin is a medication with anticoagulant and antithrombotic pharmacological effects. Different forms of heparin are available, including unfractionated heparin (UFH) and low molecular weight heparin (LMWH), which may be administered by continuous infusion, subcutaneous (SC), or intravenous injection. Subcutaneous injection is chosen when slow and continuous absorption of drugs such as insulin is required. Heparin is a nursing intervention frequently applied to patients in clinics. However, adverse side effects such as ecchymosis, hematoma and pain may occur at the injection site after subcutaneous heparin administration [1], [2]. Adverse drug reactions are a relatively common occurrence and can cause harm to patients. Studies have determined that undesirable side effects such as ecchymosis, hematoma and pain occurred after SC LMWH application [2], [3], [4], [5]. Ecchymosis occurs due to the leakage of blood under the skin from blood vessels damaged as a result of mechanical trauma. This bleeding can sometimes worsen, and more blood can pool at the injection site, resulting in hematoma and swelling [6]. Ecchymosis and hematoma cause pain and may play a limiting role in the choice of injection site for ongoing heparin treatment [4]. These local problems may affect patients' body image and self- esteem and increase the patient's physical and psychological discomfort [7]. Studies have determined that such as rotation injection site [8], cold application [4], [9], [10], use of air lock technique without aspiration [3], LMWH be given slowly [2], [5], and preferring the abdominal region [5], [11], decreased the incidence of ecchymosis, hematoma, and pain at the injection site. Despite all these precautions, ecchymosis, hematoma, and pain are common in patients after SC heparin injections.

This study investigated the effect of Hypericum perforatum (HP) oil, also known as St. John’s Wort, on ecchymosis and pain after SC LMWH injection. The use of HP dermatologically for many years has been widespread. Hypericum perforatum in topical form such as oil or tincture is used to treat minor wounds and burns, sunburns, abrasions, bruises, contusions, ulcers, and muscle pain [12]. In addition to these effects, it is also stated that it has sedative, antiseptic, antioxidant, antispasmodic and antibacterial, antiviral, antitumor, anti-inflammatory, analgesic and hepatoprotective effects [12], [13]. The European Medicines Agency (EMA) (2022) accepts the use of HP extracts for minor skin infections, healing and symptomatic treatment of small wounds [14]. World Health Organization reported that HP is used topically for the treatment of minor cuts, burns and skin ulcers, sciatica and ulcers. In addition, it is also used to treatment viral infections, bladder irritation, colds flu, diabetes, digestive disorders, hemorrhoids, neuralgia and migraine headaches [15]. Studies investigating the effect of HP on wound healing have reported that HP accelerates the wound healing process and reduces ecchymosis, hematoma and pain in the wound [16], [17], [18]. has been noted to have an analgesic effect in low doses, acute and chronic pain. Studies have shown that the pain-relieving effect is due to the substance hypericin and hyperforin [19]. Neuropathic pain is common in patients who receive oxaliplatin-based chemotherapy. The potential use of HP against chemotherapy-induced neuropathy has been proposed [13].

Consequently, administering medication safely, protecting the patient from possible medical errors and increasing patient comfort are the main objectives of clinical nurses [15]. Some measures that can reduce pain and ecchymosis after SC LMWH injection are used by nurses. Still, new strategies need to be developed. This study investigates a new application for the prevention of these complications. To our knowledge, this is the first study to investigate the effect of Hypericum perforatum extract on preventing pain and ecchymosis formation after SC LMWH injection. The specific research questions were as follows:1.

Does HP oil applied to the area before subcutaneous LMWH injection have an effect in preventing bruising at the injection site?

2.

Does HP oil applied to the area before subcutaneous LMWH injection have an effect in preventing pain at the injection site?