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LarkaDrin Capsules

Generic name: acetaminophen, dichloralphenazone, and isometheptene mucate
Dosage form: capsule
Drug class: Antimigraine agents

Medically reviewed by Last updated on June 22, 2020.

Disclaimer: This drug has not been found by FDA to be safe and effective, and this labeling has not been approved by FDA. For further information about unapproved drugs, click here.



LarkaDrin Capsules contain acetaminophen, dichloralphenazone, and isometheptene mucate. Acetaminophen has been associated with cases of acute liver failure at times resulting in liver transplant and death. Most of the cases of liver injury are associated with the use of acetaminophen at doses that exceed 4,000 milligrams per day, and often in combination with other acetaminophen-containing products.

LarkaDrin Capsules Description

Each LarkaDrin gelatin capsule contains:

Acetaminophen, USP ..... 325 mg

Dichloralphenazone, USP ..... 100 mg

Isometheptene Mucate, USP ..... 65 mg

Acetaminophen, a non-salicylate, occurs as a white, odorless, crystalline powder, possessing a slightly bitter taste. Acetaminophen is Acetamide, N-(4-hydroxyphenyl)-. It has the following structural formula:

Figure 1: Acetaminophen

C8H9NO2 M.W. 151.16

Dichloralphenazone is a white, microcrystalline powder, with slight odor and tastes saline at first, becoming acrid. It is a mild sedative. Its chemical name is: 1,2-Dihydro-1,5-dimethyl-2-phenyl-3H-pyrazol-3-one, compound with 2,2,2-trichloro-1,1-ethanediol (1:2). Dichloralphenazone has the following structural formula:

Figure 2: Dichloralphenazone

C15H18Cl6N2O5 M.W. 519.07

Isometheptene Mucate is a white crystalline powder having a characteristic aromatic odor and bitter taste. It is an unsaturated aliphatic amine with sympathomimetic properties. Its chemical name is: 6-Methylamino-2-methylheptene, tetrahydroxyadipic acid (2:1) (salt). Isometheptene mucate has the following structural formula:

Figure 3: Isometheptene Mucate

(C9H19N)2•C6H10O8 M.W. 492.65


Inactive ingredients include colloidal silicone dioxide, magnesium stearate, Povidone, sodium laurel sulfate, and starch. The gelatin capsule shells contain gelatin and the following dye systems: Iron Oxide Red, titanium dioxide, and edible printing ink prepared from ingredients conforming to applicable regulations.

LarkaDrin Capsules - Clinical Pharmacology

Acetaminophen raises the threshold to painful stimuli, thus exerting an analgesic effect against all types of headaches.

Dichloralphenazone, a mild sedative, reduces the patient's emotional reaction to the pain of both vascular and tension headaches.

Isometheptene Mucate, a sympathomimetic amine, acts by constricting dilated cranial and cerebral arterioles, thus reducing the stimuli that lead to vascular headaches.

Indications and Usage for LarkaDrin Capsules

For relief of tension and vascular headaches.*

* Based on a review of this drug (isometheptene mucate) by the National Academy of Sciences-National Research Council and/or other information, FDA has classified the other indication as "possibly" effective in the treatment of migraine headache. Final classification of the less-than-effective indication requires further investigation.


LarkaDrin Capsules are contraindicated in patients with glaucoma and/or severe cases of renal disease, hypertension, organic heart disease, hepatic disease and in those patients who are on monoamine-oxidase (MAO) inhibitor therapy.


Caution should be observed in hypertension, peripheral vascular disease and after recent cardiovascular attacks.


Hepatotoxicity - Acetaminophen has been associated with cases of acute liver failure, at times resulting in liver transplant and death. Most of the cases of liver injury are associated with the use of acetaminophen at doses that exceed 4,000 milligrams per day, and often involve more than one acetaminophen-containing product. The excessive intake of acetaminophen may be intentional to cause self-harm or unintentional as patients attempt to obtain more pain relief or unknowingly take other acetaminophen-containing products. The risk of acute liver failure is higher in individuals with underlying liver disease and in individuals who ingest alcohol while taking acetaminophen.

Instruct patients to look for acetaminophen or APAP on package labels and not to use more than one product that contains acetaminophen. Instruct patients to seek medical attention immediately upon ingestion of more than 4,000 milligrams of acetaminophen per day, even if they feel well.

Hypersensitivity/Anaphylaxis – There have been post-marketing reports of hypersensitivity and anaphylaxis associated with the use of acetaminophen. Clinical signs included swelling of the face, mouth, and throat, respiratory distress, urticaria, rash, pruritus, and vomiting. There were infrequent reports of life-threatening anaphylaxis requiring emergency medical attention. Instruct patients to discontinue LarkaDrin Capsules immediately and seek medical care if they experience these symptoms. Do not prescribe LarkaDrin Capsules for patients with acetaminophen allergy.

Adverse Reactions

Transient dizziness and skin rash may appear in hypersensitive patients. This can usually be eliminated by reducing the dose.

LarkaDrin Capsules Dosage and Administration

FOR RELIEF OF MIGRAINE HEADACHE: The usual adult dosage is two capsules at once, followed by one capsule every hour until relieved, up to 5 capsules within a twelve hour period.

FOR RELIEF OF TENSION HEADACHE: The usual adult dosage is one or two capsules every four hours up to 8 capsules a day.

How is LarkaDrin Capsules Supplied

LarkaDrin Capsules are supplied as gelatin capsules with a red cap and a white body. The capsules are imprinted "LL500", in black ink, on the body and cap.

Available in bottles of 100 capsules NDC 68047-500-01

Storage and Handling

Store at 20°- 25°C (68°- 77°F); excursions permitted to 15° to 30°C. [See USP controlled room temperature.]

All prescription substitutions using this product shall be pursuant to state statutes as applicable. This is not an Orange Book product.

Rx only

Distributed by:
Larken Laboratories, Inc.
Canton, MS 39046

500419 Rev. 03/12


acetaminophen, dichloralphenazone, and isometheptene mucate capsule
Product Information
Product Type HUMAN PRESCRIPTION DRUG LABEL Item Code (Source) NDC:68047-500
Route of Administration ORAL DEA Schedule CIV
Active Ingredient/Active Moiety
Ingredient Name Basis of Strength Strength
Inactive Ingredients
Ingredient Name Strength
Product Characteristics
Color WHITE, RED Score no score
Shape CAPSULE (hard gelatin) Size 21mm
Flavor Imprint Code LL500
# Item Code Package Description
1 NDC:68047-500-01 100 CAPSULE (CAPSULE) in 1 BOTTLE
Marketing Information
Marketing Category Application Number or Monograph Citation Marketing Start Date Marketing End Date
Unapproved drug other 07/17/2012
Labeler - Larken Laboratories, Inc. (791043719)
Name Address ID/FEI Operations
Sovereign Pharmaceuticals, LLC 623168267 MANUFACTURE(68047-500)
Larken Laboratories, Inc.

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