Pharmacology: Antiemetics and Antianemics

Antiemetics

• Serotonin antagonists: Used to prevent nausea and vomiting. Example: Ondansetron.
• Dopamine antagonists: Examples include Promethazine and Metoclopramide. These drugs often have extrapyramidal side effects, affecting motor control.
• Antihistamines: Histamine receptor antagonists, such as Diphenhydramine and Dimenhydrinate, treat nausea and vomiting. Meclizine is another example.
• Cannabinoids: Cannabis and Dronabinol are schedule I and III drugs, respectively, used as antiemetics.
• Proton Pump Inhibitors (PPIs): These drugs (e.g., Zole) decrease stomach acid production. Long-term PPI use can result in vitamin B12 deficiency.
• Erectile Dysfunction Agents: These agents (e.g., Sildenafil, Vardenafil, Tadalafil) increase nitric oxide, thus relaxing blood vessels in the penis leading to increased blood flow. Side effects include headache, flushing, back pain, and temporary vision changes.

Antianemics

• Iron Deficiency Anemia: Iron supplements are prescribed. Iron is considered a "heavy" mineral and should be taken cautiously.
• Side Effects of Iron Supplements: Possible side effects of consuming iron supplements include staining of teeth and skin, as well as tissue staining and injection side effects.
• Patient Care Considerations: Iron supplements should ideally be taken on an empty stomach for optimal absorption, but if this causes discomfort, consuming iron supplements with food can improve absorption. Antacids or tetracyclines should be taken at least two hours apart from iron supplements to avoid decreased absorption. Avoid vitamin C when taking iron to avoid absorption issues. Eating foods high in vitamin C with iron supplements reduces absorption. Space doses evenly throughout the day for optimal iron absorption and red blood cell (RBC) production. Encourage practices like consuming water, fiber, and exercise to prevent constipation. A healthy diet that includes a sufficient amount of iron is important.

Statins

• Use: Statins are commonly prescribed in the US for primary hypercholesterolemia, to prevent coronary events (like heart attacks and strokes), and to control high cholesterol, especially in patients with diabetes and/or experiencing a stroke or mini-stroke
• Mechanism: Statins lower LDL ("bad") cholesterol levels. They also protect the liver and muscles from damage caused by high cholesterol.
• Contraindications: Patients should avoid alcohol, and baseline liver function studies should be performed and monitored for at least 12 weeks and then every six months thereafter.
• Side Effects: Possible side effects include myopathy (muscle pain, weakness) and neuropathy (nerve pain, numbness). Patients should report any muscle-related symptoms immediately to their doctor.

Anticoagulants

• Heparin: Used to prevent blood clots. E.g., heparin sodium converts fibrinogen to fibrin.
• Low-Molecular-Weight Heparin: Examples such as enoxaparin and dalteparin; these have longer half-life than other heparin forms.
• Antidote for Heparin: Protamine sulfate.
• Contraindications: Active bleeding, presence of ulcers, and hemorrhagic brain injury.
• Monitoring: Regular monitoring for potential side effects such as bleeding is important.
• Avoid these: Corticosteroids and salicylates and NSAIDs, and foods/dietary supplements containing vitamin K, including leafy greens

Antiplatelets

• Mechanism: These drugs prevent blood platelets from clumping together to decrease the risk of blockage in blood vessels and prevent heart attacks or strokes. Examples include aspirin, clopidogrel (Plavix), and pentoxifyline (Trental).
• Route(s): Oral and IV
• Important Considerations: Avoid taking with foods if the patient has a peptic ulcer and be cautious in patients with or who have a history of renal or hepatic failure; these medications can exacerbate existing health issues. It is important to stay alert and monitor the patient carefully, particularly those with a history of heart attack or stroke. Avoid combining with corticosteroids to avoid increased negative side effects; be cautious in concurrent use of drugs that reduce the effectiveness of Beta-blockers

Coumadin

• Mechanism: Coumadin, also known as warfarin, works by inhibiting vitamin K.
• Route: Oral (taken by mouth)
• Monitoring: Prothrombin time (PT) and International Normalized Ratio (INR) are monitored to ensure therapeutic levels are achieved.
• Antidote: Vitamin K is the antidote.
• Contraindications: Certain conditions like severe liver disease or recent surgery
• Important Considerations: Avoid foods high in vitamin K to avoid interfering with medication effectiveness.