Please seek emergency medical care for your grandmother immediately. Do not give her any medication at home. If this is Deep Vein Thrombosis (DVT), it is a medical emergency that can lead to a life-threatening pulmonary embolism. A doctor must first confirm the diagnosis using a leg ultrasound. If DVT is confirmed, she will likely require prescription anticoagulants (blood thinners). Because of her pre-existing heart and asthma conditions, self-medicating is extremely dangerous; these blood thinners must be carefully chosen and monitored by a professional to prevent severe bleeding or drug interactions. Please take her to the nearest hospital right away.