Exam 4- Week 13

Question 1

Pseudoephedrine (Sudafed, PediaCare, Triaminic, Contac)

Answer 1

Decongestant
•Dosage:
›Adults & Adolescents >12yo: PO, 60mg Q4-6H, SR 120mg Q12H, CR 240mg Q24H
›Children > 5y/o: PO, 30mg Q4-6H, SR and CR < 12y/o not recommended
›Do not use in children under the age of four

Onset of action: 30 minutes
•Duration: 4-6 hours
•Half-life: 7 hours

Pharmacokinetics: readily absorbed from the GI tract, with onset of activity occurring within 30 min; duration ranges from 4-6H, 8-12H for ER; metabolized by liver and excreted in urine; crosses placenta and is secreted in breast milk
•Mimics actions of Sympathetic Nervous System and achieves nasal decongestant effects by vasoconstriction in nasal mucous membranes. This shrinkage decreases membrane size and promotes sinus drainage and improved airflow. Other effects include cardiovascular stimulation, constriction of renal arterioles, and anxiety.

If taken with MAOIs, guanethidine, methyldopa, or furazolidone: Hypertension
•Urinary alkalizer: potassium, sodium acetate, sodium bicarbonate: Prevents the excretion of pseudoephedrine due to alkaline urine
•Drug to herbal interactions: Ma huang (will result in blood sugar fluctuations)

Contraindications:
›Pregnancy
›Hypertension
›Coronary artery disease

Adverse effects
›Anxiety
›Increased blood pressure and pulse rate
›Restlessness
›Insomnia
›Weakness
›Skin rash
›Urticaria
›Dryness of mucous membranes

Rebound congestion: When administering for 3-5 days
•To provide relief of congestion you will need a stronger dosage
•Do not take more than 4 days
•Avoid any medications that contain pseudoephedrine

Question 2

Topical decongestants

Answer 2

Used especially in patients with nasal decongestants and HTN.

Question 3

Antihistamines

Answer 3

• Used to treat allergic rhinitis, pruritis, urticaria, insomnia, N/V, cold symptoms
• Block the action of histamine by binding to histamine receptors
• Well absorbed orally – biotransformed by the CYP450 system
• Side effects – anticholinergic effects associated with first-generation antihistamines

Contraindications: narrow-angle glaucoma, lower respiratory tract symptoms (they thicken secretions and impair expectoration), stenosing peptic ulcer, symptomatic prostatic hypertrophy, bladder neck obstruction, pyloroduodenal obstruction, and MAOI

Question 4

Codeine

Answer 4

Codeine works as an antitussive through direct action on receptors in the cough center of the medulla, at lower doses than is required for analgesia.

Question 5

Antitussives

Answer 5

The drugs that can affect this complex mechanism are diverse, ranging from bronchodilators to drugs that act centrally or peripherally to suppress cough. The nonprescription antitussives are dextromethorphan and benzonatate. Codeine is also used as an antitussive.

Question 6

Expectorants

Answer 6

Guaifenesin (Mucinex, Robitussin)
•Used for the management of cough associated with bronchitis, colds, sinusitis, etc.
•Increases the output of the respiratory tract by decreasing adhesiveness and surface tension.
•Rapidly absorbed after oral administration
•Side effects – GI

Question 7

Oseltamivir (Tamiflu)

Answer 7

• Onset: Rapid
• Duration: Unknown
• Half-life: 6-10 hours
• Action: Influenza neuraminidase inhibitor.
• Oseltamivir is a prodrug that is metabolized into oseltamivir carboxylate, which is the active drug. Excreted 99% through the kidneys.

Question 8

Dextromethorpan

Answer 8

Use: Treatment of nonproductive cough
•Absorbed rapidly from the GI tract with antitussive activity occurring within 15-30 minutes. Undergoes extensive hepatic metabolism, excretion mainly renal, half life 11 hours.

May potentiate sedation when used with other CNS depressants. May interact with MAOIs resulting in serotonin syndrome (nausea, hypotension, excitation, hyperpyrexia, coma). May also interact with fluoxetine, quinidine, sibutramine, linezolid, amiodarone.
•Grapefruit and orange juices inhibit metabolism and intestinal reflux, resulting in increased risk of pharmacologic and adverse effects that last several days, may contain aspertame (pts with PKU)

Contraindications: hypersensitivity, MAOI use within 14 days, patients < 6 years old, patients treating chronic cough d/t emphysema or asthma, patients with hepatic impairment, pregnancy, pregnancy category C

Adverse Effects:
›Nausea
›Vomiting
›Dizziness
›Irratibility
›Dextromethorphan poisoining:
•First plateau: 100-200 mg Mild stimulation
•Second plateau: 200-400 mg Euphoria/Hallucinations
•Third plateau: 300-600 mg Dissociate state
•Fourth plateau: >600 mg Complete dissociation/unresponsiveness

Patient teaching
›Explain that the purpose is to quiet a cough, emphasize side effects such as sedation and drowsiness,
›Do not drive or perform tasks that require alertness,
›Do not take if pt has ever had an allergic reaction
›Do not take it if pregnant or history of liver problems
›Use cautiously if pt is taking antidepressants
›do not take with alcohol
›Keep out of reach of children
›Report any chest tightness, SOB,
›Has a potential for abuse

Question 9

Fexofenadine (Allegra)

Answer 9

Uses: Prototype antihistamine
•Dosage:
›Adults & Adolescents >12yo: PO 60mg BID or 180mg everyday
›Children 6-11 y/o: PO 30mg BID
›Children 2-11 y/o: oral suspension, 30mg (5mL) BID
›Children 6 mos to 2 yrs: 15mg (2.5mL) BID
•Onset: 1-2 H
•Duration: 12 H
•Half-life: 14 H

Pharmacokinetics: taken orally and absorbed rapidly; peak drug effect is seen within 2-6 hours; 5% metabolized in liver, 80% in feces, 11% in urine
•Pharmacodynamics: selectively blocks effects of histamine at H-receptor sites, decreasing allergic response; has anticholinergic and antipruritic effects (binds to lung receptors more than it binds to cerebellar receptors, resulting in a reduced sedative potential
•Drug to drug interactions: rifampin (reduces absorption of fexofenadine), antacids (decreases efficacy), Ca carbonate (decreases efficacy), famotidine (decreases efficacy), magnesium hydroxide (decreases efficacy)

Contraindications: should not be used in a patient with hypersensitivity to fexofenadine o(which is no longer manufactured); pregnancy category C; crosses placenta and enters breast milk; used with caution in pts with renal impairment (half life is prolonged, increased peak plasma levels)
•Adverse effects: viral infections (colds and flu); n/v; dysmenorrhea; drowsiness; dyspepsia; fatigue; prolonged QT interval

Guidelines for adm: pt’s health status, allergy to any antihistamines, pregnancy, lactation, renal impairment, assess respiratory system, use precautions in elderly, avoid apple, grapefruit, and orange juice, assess level of sedation caused by drug before driving or performing tasks that involve concentration
•Pt teaching: caution not to take if pt has every had an allergic rxn to antihistamines; take as prescribed; avoid use of other OTC meds; avoid alcohol while taking; take with food if GI upset; take with a glass of water; report any adverse effects; encourage use of humidifier, drink fluids, avoid overly dry places and smoke-filled areas