Logo

OpiCalc

FavoritesSpecialtiesDrugsGuidelinesMost Used

Quick Access

Favorites
Most Used

All Specialties

OpiCalc Logo
Clinical CalculatorsDrugsGuidelines
SpecsDrugsGuides
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
‌
OpiCalc Logo

OpiCalc

Easy, fast, and private medical tools for clinicians. Always free.

No Login Required
Ready for the Bedside

Resources

About UsEditorial PolicyMedical DisclaimerPrivacy PolicyTerms of UseCookie Policy

Support

Contact Us

Clinical Notice:OpiCalc is not a substitute for professional clinical judgment. Always verify dosages and guidelines.

OpiCalc © 2018-2026

•

All Rights Reserved

Registry Hub
Peer-Reviewed Evidence
HomeDrug RegistryCompareACETAMINOPHEN CAFFEINE AND DIHYDROCODEINE BITARTRATE vs MINITRAN
Comparative Pharmacology

ACETAMINOPHEN CAFFEINE AND DIHYDROCODEINE BITARTRATE vs MINITRAN Comparison

Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.

Clinical EssentialsPharmacokineticsSpecial PopulationsSafety & MonitoringPregnancy & LactationClinical Insights
Differential Analysis

ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE vs MINITRAN

Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.

View ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE Monograph View MINITRAN Monograph
ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE
Opioid Agonist
Category D/X
MINITRAN
Nitrate Vasodilator
Category C
TL;DR — Key Differences
  • Drug class: ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE is a Opioid Agonist; MINITRAN is a Nitrate Vasodilator.
  • Half-life: ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE has a half-life of Acetaminophen: 2-3 hours (normal), prolonged in hepatic impairment. Caffeine: 3-6 hours (adults), prolonged in liver disease or with oral contraceptives. Dihydrocodeine: 3.5-6 hours (terminal). Clinical context: q6h dosing interval appropriate; accumulation risk in renal/hepatic impairment.; MINITRAN has Terminal half-life is approximately 1-4 minutes for nitroglycerin; clinical effect duration is longer due to tissue distribution..
  • No direct drug-drug interaction has been documented between ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE and MINITRAN.
  • Pregnancy: ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE is rated Category D/X; MINITRAN is rated Category C.

Last clinically reviewed: July 2026 · OpiCalc Medical Review Team

Clinical Essentials

ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE
MINITRAN
Mechanism of Action
ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE

Acetaminophen: inhibits cyclooxygenase (COX) activity, reducing prostaglandin synthesis; analgesic and antipyretic. Caffeine: adenosine receptor antagonist; enhances analgesic effect. Dihydrocodeine: mu-opioid receptor agonist; produces analgesia via central opioid receptors.

MINITRAN

Nitroglycerin is converted to nitric oxide (NO) in vascular smooth muscle, which activates guanylyl cyclase, increasing c GMP levels. This leads to dephosphorylation of myosin light chains and vasodilation, particularly in venous capacitance vessels and coronary arteries, reducing preload and afterload.

Indications
ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE

Management of mild to moderate pain where treatment with an opioid is appropriate and for which alternative treatments are inadequate,Off-label: acute pain, chronic pain

MINITRAN

Acute angina pectoris,Prophylaxis of angina pectoris (prior to activities that may provoke an attack),Chronic angina (off-label: long-term prophylaxis),Heart failure associated with acute myocardial infarction (off-label)

Standard Dosing
ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE

1-2 tablets (each containing acetaminophen 300 mg, caffeine 30 mg, dihydrocodeine bitartrate 20 mg) orally every 4-6 hours as needed for pain; maximum 8 tablets per day.

MINITRAN

Minitran (nitroglycerin transdermal) is applied as a transdermal patch. Initial dose: 0.2-0.4 mg/hour applied once daily. Titrate based on response and tolerance. Maximum dose: 0.8 mg/hour. The patch is worn for 12-14 hours daily with a 10-12 hour nitrate-free interval to prevent tolerance.

Direct Interaction
ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE
No Direct Interaction
MINITRAN
No Direct Interaction

Pharmacokinetics

ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE
MINITRAN
Half-Life
ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE

Acetaminophen: 2-3 hours (normal), prolonged in hepatic impairment. Caffeine: 3-6 hours (adults), prolonged in liver disease or with oral contraceptives. Dihydrocodeine: 3.5-6 hours (terminal). Clinical context: q6h dosing interval appropriate; accumulation risk in renal/hepatic impairment.

MINITRAN

Terminal half-life is approximately 1-4 minutes for nitroglycerin; clinical effect duration is longer due to tissue distribution.

Metabolism
ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE

Acetaminophen: primarily hepatic via glucuronidation and sulfation; minor CYP2E1, CYP1A2, CYP3A4. Caffeine: hepatic via CYP1A2. Dihydrocodeine: O-demethylation to dihydromorphine via CYP2D6; also via CYP3A4.

MINITRAN

Rapidly metabolized in the liver by glutathione-organic nitrate reductase, with minor contributions from vascular wall and RBC metabolism. Metabolites include 1,2-glyceryl dinitrate and 1,3-glyceryl dinitrate.

Excretion
ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE

Acetaminophen: renal excretion of metabolites (glucuronide 60%, sulfate 30%, cysteine/mercapturate 8%), <5% unchanged. Caffeine: renal excretion of metabolites (1-methyluric acid, 1-methylxanthine, etc.), <2% unchanged. Dihydrocodeine: renal excretion of metabolites (dihydrocodeine-6-glucuronide, nordihydrocodeine, dihydromorphine), ~20% unchanged. Overall, predominantly renal (≥85%), minor biliary/fecal.

MINITRAN

Primarily renal excretion of inactive metabolites; less than 1% excreted unchanged. Biliary/fecal elimination is minimal.

Protein Binding
ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE

Acetaminophen: 10-25% (albumin). Caffeine: 25-36% (albumin). Dihydrocodeine: ~20-30% (albumin and α1-acid glycoprotein).

MINITRAN

Approximately 60% bound to plasma proteins (albumin).

VD (L/kg)
ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE

Acetaminophen: 0.7-1.0 L/kg. Caffeine: 0.5-0.8 L/kg. Dihydrocodeine: 1.0-1.5 L/kg. Clinical meaning: moderate distribution, potential for central nervous system penetration.

MINITRAN

Vd is about 3 L/kg, indicating extensive tissue distribution.

Bioavailability
ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE

Acetaminophen: oral 75-85%. Caffeine: oral ~100%. Dihydrocodeine: oral ~20-30% (first-pass metabolism; extended-release formulations have altered bioavailability).

MINITRAN

Transdermal: approximately 70-80% of the dose reaches systemic circulation.

Special Populations

ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE
MINITRAN
Renal Adjustments
ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE

GFR 30-50 m L/min: administer every 6 hours; GFR 10-30 m L/min: administer every 8 hours; GFR <10 m L/min: administer every 12 hours; avoid in severe impairment due to dihydrocodeine accumulation.

MINITRAN

No specific dose adjustment required for renal impairment. However, patients with severe renal insufficiency (Cr Cl <30 m L/min) may have increased risk of adverse effects; monitor closely.

Hepatic Adjustments
ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE

Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50% or extend interval to every 8 hours; Child-Pugh C: avoid use due to acetaminophen hepatotoxicity and dihydrocodeine accumulation.

MINITRAN

No specific dose adjustment recommended for Child-Pugh A or B. For Child-Pugh C (severe hepatic impairment), consider reducing dose due to reduced metabolism and increased risk of hypotension; use with caution.

Pediatric Dosing
ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE

Not recommended for children under 12 years due to dihydrocodeine risks; for adolescents 12-18 years: 1 tablet orally every 4-6 hours as needed, maximum 4 tablets per day (weight-based dosing not established).

MINITRAN

Safety and effectiveness in pediatric patients have not been established. Use only under expert guidance. Typical initial dose: 0.1-0.2 mg/hour transdermally, titrated cautiously based on clinical response and tolerance.

Geriatric Dosing
ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE

Initiate with 1 tablet orally every 6 hours; caution due to increased sensitivity to opioids and hepatotoxicity from acetaminophen; maximum 4 tablets per day; monitor renal and hepatic function.

MINITRAN

Elderly patients may be more sensitive to the hypotensive effects. Start at the lower end of dosing range (0.2 mg/hour) and titrate slowly. Monitor blood pressure and heart rate regularly.

Safety & Monitoring

ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE
MINITRAN
Black Box Warnings
ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE
FDA Black Box Warning

Risk of addiction, abuse, and misuse; life-threatening respiratory depression; accidental ingestion of acetaminophen can cause fatal hepatotoxicity; concomitant use with benzodiazepines or CNS depressants may cause profound sedation, respiratory depression, coma, and death; neonatal opioid withdrawal syndrome with prolonged use during pregnancy.

MINITRAN
FDA Black Box Warning

Do not use MINITRAN in patients taking phosphodiesterase-5 inhibitors (e.g., sildenafil, tadalafil, vardenafil) as this can cause severe hypotension. Additionally, MINITRAN should not be used in patients with early myocardial infarction or severe anemia.

Warnings/Precautions
ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE

Addiction, abuse, and misuse; respiratory depression; acetaminophen hepatotoxicity; drug interaction with benzodiazepines and CNS depressants; neonatal opioid withdrawal syndrome; risk of serotonin syndrome; severe hypotension; adrenal insufficiency; use in patients with head injury or increased intracranial pressure; seizures; avoid in patients with severe hepatic impairment.

MINITRAN

Hypotension; paradoxical bradycardia; tolerance (need for nitrate-free interval); exacerbation of angina with abrupt discontinuation; use with caution in patients with volume depletion, hypotension, or hypertrophic cardiomyopathy.

Contraindications
ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE

Hypersensitivity to any component; significant respiratory depression; acute or severe bronchial asthma; GI obstruction; suspected surgical abdomen; concomitant use with MAOIs or within 14 days; severe hepatic impairment.

MINITRAN

Concurrent use of phosphodiesterase-5 inhibitors (e.g., sildenafil, tadalafil, vardenafil); severe anemia; increased intracranial pressure (e.g., head trauma, cerebral hemorrhage); acute circulatory failure; hypersensitivity to nitrates.

Adverse Reactions
ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE
Data Pending
MINITRAN
Data Pending
Food Interactions
ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE

Avoid alcohol; may increase risk of hepatotoxicity and CNS depression. High-fat meals may delay absorption but do not significantly affect overall exposure. Caffeine-containing foods and beverages may increase stimulant effects.

MINITRAN

Concurrent use of alcohol can cause vasodilation and hypotension. Limit or avoid alcohol. No specific food restrictions.

Pregnancy & Lactation

ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE
MINITRAN
Teratogenic Risk
ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE

Acetaminophen: Generally considered low risk; no consistent evidence of teratogenicity. Caffeine: High doses (>200 mg/day) associated with increased miscarriage risk; limited data on malformations. Dihydrocodeine: Opioid; first trimester: increased risk of neural tube defects (OR 2.0-2.5); third trimester: risk of neonatal opioid withdrawal syndrome (NOWS). Overall, combination product should be used only if benefit outweighs risks.

MINITRAN

Category C. Animal studies show fetal harm; no adequate human studies. Use only if maternal benefit outweighs risk. First trimester: possible teratogenic effects. Second/third trimesters: risk of fetal bradycardia, hypotension, and decreased placental perfusion.

Lactation Summary
ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE

Acetaminophen: Excreted in breast milk (M/P ratio ~0.9); safe at therapeutic doses. Caffeine: Excreted (M/P ~0.5-0.8); moderate intake (<300 mg/day) generally safe. Dihydrocodeine: Excreted in low levels; however, interindividual variability in metabolism (CYP2D6) may lead to higher morphine concentrations in some infants; risk of neonatal respiratory depression. M/P ratio not well established for dihydrocodeine. Use with caution, monitor infant for sedation and feeding difficulties.

MINITRAN

Likely excreted in breast milk. M/P ratio not established. Use with caution; monitor infant for hypotension.

Pregnancy Dosing
ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE

No specific dose adjustments for pregnancy due to lack of pharmacokinetic studies for this combination. However, note: Increased clearance of acetaminophen in pregnancy may require higher doses for analgesia but remains within standard limits. Caffeine clearance decreases in third trimester; consider reducing intake to <200 mg/day. Dihydrocodeine: Increased volume of distribution and clearance in pregnancy; dose may need titration but no established guidelines. Use lowest effective dose for shortest duration.

MINITRAN

No specific dose adjustments recommended, but use lowest effective dose due to potential for hypotension and decreased placental perfusion.

Maternal Safety Status
ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE
Category D/X
MINITRAN
Category C

Clinical Insights

ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE
MINITRAN
Clinical Pearls
ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE

Dihydrocodeine is a prodrug requiring CYP2D6 metabolism to active metabolites; poor metabolizers may have reduced efficacy while ultrarapid metabolizers risk toxicity. Caffeine potentiates analgesia and may cause insomnia with evening use. Do not exceed 8 tablets per 24 hours due to acetaminophen hepatotoxicity risk. Use with caution in elderly and patients with renal impairment.

MINITRAN

MINITRAN (nitroglycerin transdermal) is used for angina prophylaxis, not acute attacks. Apply to hairless area, rotate sites, and remove for 12-14 hours daily to prevent tolerance. If headache occurs, reduce dose or use acetaminophen. Do not discontinue abruptly to avoid rebound ischemia.

Patient Counseling
ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE

Take with food if stomach upset occurs.,Avoid alcohol and products containing acetaminophen to prevent liver damage.,Do not exceed 8 tablets in 24 hours.,May cause drowsiness; avoid driving or operating machinery until you know how this medication affects you.,If you have a history of drug dependence, use with caution as dihydrocodeine can be habit-forming.

MINITRAN

Apply patch to clean, dry, hairless skin on chest, arm, or back; rotate sites daily.,Remove patch after 12-14 hours to prevent tolerance; apply new patch at same time next morning.,Do not use for acute angina; use sublingual nitroglycerin instead.,Avoid alcohol and erectile dysfunction drugs like sildenafil; can cause severe hypotension.,Headache may occur; use acetaminophen or reduce dose; do not stop abruptly.

Safety Verification

Known Interactions

ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE Risks3
Chlordiazepoxide + Dihydrocodeine
moderate

"The combination of chlordiazepoxide, a benzodiazepine that enhances GABAergic inhibition, and dihydrocodeine, an opioid agonist primarily at mu-receptors, results in additive central nervous system (CNS) depression. This synergy increases the risk of profound sedation, respiratory depression, coma, and death, particularly in vulnerable populations such as the elderly or those with pre-existing respiratory compromise. Concurrent use also elevates the potential for hypotension and psychomotor impairment, leading to falls or accidents."

Reserpine + Dihydrocodeine
moderate

"Reserpine depletes catecholamines in the central nervous system and peripheral adrenergic neurons, leading to reduced sympathetic outflow. Dihydrocodeine, an opioid agonist, can cause further central nervous system depression and hypotension. When combined, there is an additive risk of excessive hypotension, bradycardia, and profound sedation, potentially leading to falls or respiratory depression."

Dihydrocodeine + Clemastine
moderate

"Dihydrocodeine, an opioid analgesic, undergoes O-demethylation primarily via CYP2D6 to form dihydromorphine, which contributes to its analgesic effects. Clemastine, a first-generation antihistamine, is metabolized mainly by CYP2D6 as well. When co-administered, clemastine competitively inhibits CYP2D6, reducing the clearance of dihydrocodeine and decreasing the formation of the active metabolite dihydromorphine. This can lead to diminished analgesic efficacy and potentially increased levels of parent dihydrocodeine, heightening the risk of opioid-related adverse effects such as respiratory depression, sedation, and constipation."

MINITRAN Risks

No interactions on record

Compare Alternatives

Related Drug Comparisons

Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.

ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE vs ACETAMINOPHEN AND CODEINE PHOSPHATEOpioid Agonist
MINITRAN vs ACETAMINOPHEN AND CODEINE PHOSPHATEOpioid Agonist
ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE vs ACETAMINOPHEN AND HYDROCODONE BITARTRATEOpioid Agonist
MINITRAN vs ACETAMINOPHEN AND HYDROCODONE BITARTRATEOpioid Agonist
ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE vs ACETAMINOPHEN AND PENTAZOCINE HYDROCHLORIDEOpioid Agonist-Antagonist
MINITRAN vs ACETAMINOPHEN AND PENTAZOCINE HYDROCHLORIDEOpioid Agonist-Antagonist
ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE vs ACETAMINOPHEN, ASPIRIN, AND CODEINE PHOSPHATEOpioid Agonist
MINITRAN vs ACETAMINOPHEN, ASPIRIN, AND CODEINE PHOSPHATEOpioid Agonist
ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE vs ACETAMINOPHEN; OXYCODONE HYDROCHLORIDEOpioid Agonist
Clinical Q&A

Frequently Asked Questions

Common clinical questions about ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE vs MINITRAN, answered by our medical review team.

1. What is the main difference between ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE and MINITRAN?

ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE is a Opioid Agonist that works by Acetaminophen: inhibits cyclooxygenase (COX) activity, reducing prostaglandin synthesis; analgesic and antipyretic. Caffeine: adenosine receptor antagonist; enhances analgesic effect. Dihydrocodeine: mu-opioid receptor agonist; produces analgesia via central opioid receptors.. MINITRAN is a Nitrate Vasodilator that works by Nitroglycerin is converted to nitric oxide (NO) in vascular smooth muscle, which activates guanylyl cyclase, increasing c GMP levels. This leads to dephosphorylation of myosin light chains and vasodilation, particularly in venous capacitance vessels and coronary arteries, reducing preload and afterload.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.

2. Which is stronger: ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE or MINITRAN?

Potency comparisons between ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE and MINITRAN depend on the specific clinical indication. These are agents from distinct pharmacological classes and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.

3. What is the standard dosing for ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE vs MINITRAN?

The standard adult dose of ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE is: 1-2 tablets (each containing acetaminophen 300 mg, caffeine 30 mg, dihydrocodeine bitartrate 20 mg) orally every 4-6 hours as needed for pain; maximum 8 tablets per day.. The standard adult dose of MINITRAN is: Minitran (nitroglycerin transdermal) is applied as a transdermal patch. Initial dose: 0.2-0.4 mg/hour applied once daily. Titrate based on response and tolerance. Maximum dose: 0.8 mg/hour. The patch is worn for 12-14 hours daily with a 10-12 hour nitrate-free interval to prevent tolerance.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.

4. Can you take ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE and MINITRAN together?

No direct drug-drug interaction has been formally documented between ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE and MINITRAN in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.

5. Are ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE and MINITRAN safe during pregnancy?

The maternal-fetal safety profiles differ. ACETAMINOPHEN, CAFFEINE AND DIHYDROCODEINE BITARTRATE is classified as Category D/X. Acetaminophen: Generally considered low risk; no consistent evidence of teratogenicity. Caffeine: High doses (>200 mg/day) associated with increased miscarriage risk; limited data . MINITRAN is classified as Category C. Category C. Animal studies show fetal harm; no adequate human studies. Use only if maternal benefit outweighs risk. First trimester: possible teratogenic effects. Second/third trim. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.