Generic Name

Methylphenidate Hydrochloride

---

Classification

FDA Approved Indications

• Attention Deficit Hyperactivity Disorder (ADHD)
• Narcolepsy

Mechanism of Action

Methylphenidate blocks the reuptake of dopamine and norepinephrine into presynaptic neurons, increasing their concentrations in the synaptic cleft and stimulating the postsynaptic receptors.

Dosage and Administration

Adult: Dosing varies widely; usually 5-20 mg taken 2-3 times daily, titrated as needed. Extended-release formulations are usually once daily.

Pediatric: Starting dose often 5 mg twice daily, titrated as needed. Extended-release formulations are once daily.

Geriatric: Use with caution; start at lower end of dosing range due to potential for increased sensitivity.

Renal Impairment: Adjust dose cautiously; monitor carefully.

Hepatic Impairment: Use with caution; no specific dose adjustments established.

Pharmacokinetics

Absorption: Rapidly absorbed from gastrointestinal tract.

Distribution: Extensively distributed; crosses the blood-brain barrier.

Metabolism: Hepatic de-esterification to ritalinic acid, an inactive metabolite.

Excretion: Primarily renal; elimination half-life approximately 2-3 hours (immediate release), longer for extended-release formulations.

Half Life: 2-3 hours (immediate release), varies for extended formulations.

Contraindications

• Known hypersensitivity to methylphenidate or other stimulants.
• Advanced arteriosclerosis, symptomatic cardiovascular disease, moderate to severe hypertension, hyperthyroidism, glaucoma, history of drug abuse.

Precautions

• Use with caution in patients with history of psychiatric disorders, Tourette’s syndrome, or seizure disorders. Monitoring is essential for psychological effects. Use during pregnancy only if benefits outweigh risks; consider alternative during lactation.

Adverse Reactions - Common

• Insomnia (Common)
• Decreased appetite (Common)
• Anxiety (Common)
• Nausea (Common)

Adverse Reactions - Serious

• Cardiovascular events (e.g., hypertension, tachycardia) (Serious but less common)
• Psychiatric effects (e.g., new or worsening psychosis, mania) (Serious but less common)
• Growth suppression in children (Potential with long-term use)

Drug-Drug Interactions

• Monoamine oxidase inhibitors (risk of hypertensive crisis)
• Blood pressure medications (may alter efficacy)
• Other CNS stimulants

Drug-Food Interactions

N/A

Drug-Herb Interactions

• St. John's Wort (may increase CNS stimulation)

Nursing Implications

Patient/Family Teaching

• Take medication exactly as prescribed. Do not double doses.
• Report any chest pain, shortness of breath, or palpitations.
• Monitor for appetite suppression and growth.
• Avoid alcohol and recreational drugs.
• Maintain scheduled follow-up visits.

Special Considerations

Black Box Warnings:

• Potential for abuse and dependence; misuse may lead to sudden death or serious cardiovascular adverse events.

Genetic Factors: Consider pharmacogenetic testing if available for variability in response.

Lab Test Interference: May cause false positives in drug screenings for amphetamines.

Overdose Management

Signs/Symptoms: Euphoria, agitation, confusion, hallucinations, hyperreflexia, dystonia, seizures, circulatory collapse, coma.

Treatment: Supportive care, activated charcoal if recent ingestion, benzodiazepines for seizures, cardiovascular support as needed.

Storage and Handling

Storage: Store at room temperature away from moisture, heat, and light.

Stability: Stable under recommended conditions for specified shelf life.